More Evidence of the Risk of Infectious Diseases Associated with Raw Pet Foods

I try to keep track of new research on the subject of raw food for pets. So far, the research only allows us to conclude:

  1. There is no evidence to support claims that raw diets are healthier than cooked commercial foods.
  2. There is consistent evidence that raw diets are contaminated with potentially harmful bacteria.
  3. It is not yet clear what the likelihood of infections in people or pets from these bacteria.
  4. Raw bones, often included in raw diets, may reduce calculus and periodontal disease risk, though this isn’t clearly demonstrated. However, they also present a real danger of injury, including broken teeth.
  5. Most homemade raw diets, and some commercial raw diets, may have significant nutritional deficiencies.

The latest study adds to point number 2, that such diets are far more likely than cooked pet foods to be contaminated with bacteria that can cause disease in humans and other animals.

Nemser SM, Doran T, Grabenstein M, et al. Investigation of Listeria, Salmonella, and Toxigenic Escherichia coli in Various Pet Foods. Foodborne Pathog Dis. 2014 Sep;11(9):706-9. doi: 10.1089/fpd.2014.1748. Epub 2014 May 13.

Conducted by the FDA Center for Veterinary Medicine, this study looked at over 1000 food samples over a two-year period. The results clearly show that the risk of contamination with disease-causing organisms is much greater for raw commercial foods than for cooked pet diets.

Of the 480 dry and semimoist samples, only 2 tested positive: 1 for Salmonella and 1 for Listeria greyii. However, of the 576 samples analyzed during Phase 2, 66 samples were positive for Listeria (32 of those were Listeria monocytogenes) and 15 samples positive for Salmonella. These pathogens were isolated from raw foods and jerky-type treats…

This study showed that raw pet foods may harbor food safety pathogens, such as Listeria monocytogenes and Salmonella. Consumers should handle these products carefully, being mindful of the potential risks to human and animal health.

While this doesn’t answer many of the other questions about the risks and benefits of raw diets, it strengthens the position that until some tangible benefits are shown through controlled scientific research, not simply armchair theorizing and anecdotes, there is little reason to take the risk of feeding these diets to our pets. If proponents of these diets want to convince the rest of us the risk of disease is worth taking, they have to do more than say, “It makes sense” or “It worked for me.” They will need to produce genuine scientific data to show the benefits they claim are real and greater than the risks.

Posted in Nutrition | 3 Comments

From the JREF Swift Blog- Alternative Medicine & Placebo Effects: In Pets?

My first contribution to the Swift blog at the James Randi Educational Foundation (JREF) is up today.

Alternative Medicine & Placebo Effects: In Pets?

Placebo effects, of course, operate for all medical therapies, effective or ineffective, conventional or alternative. But when considering alternative therapies, it is especially important to be aware of such effects because these therapies usually lack convincing scientific evidence that they have benefits beyond that of a placebo. As mentioned, uncommon alternative therapies like acupuncture and homeopathy are no better validated scientifically for pets than for people. Even some of the most commonly used therapies, like glucosamine, which is ubiquitous in the treatment of arthritis in old dogs and cats, often lack any reliable evidence they actually help.

Because the false impression of a benefit from an ineffective therapy can truly harm our animal companions, who cannot speak for themselves or tell us directly when we have failed to relieve their symptoms, it is especially important to insist on reliable, controlled scientific evidence for the safety and efficacy of the therapies we use for our pets.

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Acupuncture Works! (Just as Well as Fake Acupuncture Anyway)

The evidence has been accumulating for some time that acupuncture is an elaborate and very potent placebo that can effectively make subjective symptoms better without actually influencing the underlying disease. I have written about a number of studies illustrating this (e.g.  1, 2), and a new one has recently been published.

Rana S. Hinman;  Paul McCrory; Marie Pirotta; et al. Acupuncture for Chronic Knee Pain:  A Randomized Clinical Trial. JAMA. 2014;312(13):1313-1322. doi:10.1001/jama.2014.12660.

This study compared “real” acupuncture using needles and lasers with sham laser acupuncture and a no treatment group. Predictably, all the therapies showed a short-term benefit compared to nothing, but the sham therapy was just as successful (or unsuccessful) as the real therapy:

Analyses showed neither needle nor laser acupuncture significantly improved pain (mean difference; ?0.4 units; 95% CI, ?1.2 to 0.4, and ?0.1; 95% CI, ?0.9 to 0.7, respectively) or function (?1.7; 95% CI, ?6.1 to 2.6, and 0.5; 95% CI, ?3.4 to 4.4, respectively) compared with sham at 12 weeks. Compared with control, needle and laser acupuncture resulted in modest improvements in pain (?1.1; 95% CI, ?1.8 to ?0.4, and ?0.8; 95% CI, ?1.5 to ?0.1, respectively) at 12 weeks, but not at 1 year. Needle acupuncture resulted in modest improvement in function compared with control at 12 weeks (?3.9; 95% CI, ?7.7 to ?0.2) but was not significantly different from sham (?1.7; 95% CI, ?6.1 to 2.6) and was not maintained at 1 year. There were no differences for most secondary outcomes and no serious adverse events.

In patients older than 50 years with moderate or severe chronic knee pain, neither laser nor needle acupuncture conferred benefit over sham for pain or function.

Such studies clearly show that while acupuncture might make you feel better temporarily, via the placebo effect, it does not produce a real or lasting improvement. This is the definition of a placebo, and while people should be free to seek placebos to feel subjectively better if they want to, they should not be fooled into thinking the effects are real or that truly effective therapies are not needed. And in the case of our pets, it is very likely that the placebo benefits of acupuncture accrue only to us, and that while we feel as if we have helped our pets, we really have not. It is in this misconception, more than the rare physical injuries associated with acupuncture, that the real risk in this treatment methods lies.

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The University of Florida’s Integrative Medicine Service: Good Science or a CAM Trojan Horse?

The American Holistic Veterinary Medical Foundation (AHVMF) recently announced the winner of their 2014 education grant. The University of Florida will receive the $10,000 award for demonstrating “their intent and ability to become a force in integrative veterinary medicine.”

I have discussed the term “integrative medicine” before and how it serves as a Trojan horse for smuggling untested or pseudoscientific ideas into academic institutions. Integrative medicine usually means mixing alternative therapies, by definition either unproven or disproven therapies, with conventional science-based medicine as if they were epistemologically or scientifically equivalent. It allows proponents of these therapies to make them more familiar to conventional doctors, which builds a sense of confidence in the methods independent of any research evidence showing they work.

In academia, the push for integration of alternative therapies into the mainstream is also often cloaked in the language or evidence-based medicine. It is claimed that bringing “experts” in these methods into the university will facilitate sound scientific research to determine if they are truly safe and effective. While this is a noble idea, it is often put forward disingenuously by advocates of CAM who are already convinced beyond any doubt that their methods work and who have no willingness to abandon any of them regardless of what the evidence turns out to show. The leaders of the AHVMF have demonstrated repeatedly that their beliefs do not require scientific validation (e.g. 1, 2). It is quite clear that the real purpose of AHVMF grants is not to study CAM and identify both effective and ineffective therapies but to market CAM and develop scientific camouflage for ideas they have no intention of ever truly questioning.

The University of Florida School of Veterinary Medicine is becoming a regular participant in the infiltration of unscientific ideas and practices into ostensibly science-based veterinary medicine. This is the second $10,000 grant the university has accepted from the AHVMF, the first specifically intended to support the school’s acupuncture program. There is a close and reciprocal relationship between alternative medicine advocates and the UF Integrative Medicine service which is much like the potentially problematic relationships often seen between universities and other private industries, such as pet food companies and pharmaceutical companies. In addition to the AHVMF funding, two faculty members in this program are also faculty at the Chi Institute, a leading organization teaching and promoting the pseudoscience of Traditional Chinese Veterinary Medicine (TCVM). And the school has a nutrition residency which is jointly sponsored by the Chi Institute and the pet food company Waltham.

As is typical for integrative medicine departments, the University of Florida group tends to speak both the language of science and the language of alternative medicine freely, even when these contradict one another. The school’s statement on acupuncture cites many conventional mechanisms proposed to explain the possible medical effects of this therapy, including stimulation of nerves, releases of endogenous opioids and endorphins, and so on. These are certainly plausible hypotheses, though despite a great deal of effort they have not been consistently validated by research, so they are still unproven hypotheses. However, the same document employs the mystical, pre-scientific language of TCVM: “There are 361 acupuncture points located throughout the body on meridians. Meridians are the energetic channels that connect all the points to each other.” Unfortunately, acupuncture points probably don’t exist, and the “energy” referred to here is a vitalistic concept that serves no legitimate purpose in scientific medicine.

This document goes on to talk about aspects of acupuncture that clearly depend on an acceptance of traditional, pre-scientific theories of health and disease:

Hemo-acupuncture is performed by inserting a hypodermic needle into a blood vessel that contains an acupoint to draw a few drops of blood. The purpose of this modality is to release heat from the body.

[This is clearly a form of bloodletting, an ancient and completely useless medical therapy found in Europe as well as China and abandoned by science-based medicine long ago. Much of what is described today by acupuncture proponents as ancient acupuncture was likely really bloodletting.]

Moxibustion is a form of stimulation that works by warming the acupoint and causing activation of the point. It uses crushed dried leaves of Artemisia argyi rolled into a cigar-shaped fashion. The herb is burned and then placed over an acupoint without touching the skin. The warming effect of the burned herb causes stimulation of the acupoint….Be cautious when using moxibustion in the summertime because it warms the body and might lead to too much heat.

[Again, this refers to the notion of disease caused by imbalances in theoretical concepts like warm and cold, dry and damp which are distinct from the ordinary meanings of these terms. It is essentially the same as the Western Humoral Medicine which underlay all the ineffective pre-scientific medical practices used in Europe and North America prior to the development of science-based medicine]

In another example of the inconsistencies that arise from the doublethink of trying to practice science-based medicine and pre-scientific ritualistic medicine like TCVM, one of the UF professors admits, unusually for a proponent of acupuncture, that the modern practice is not likely to have much relationship to ancient Chinese medical practices: “There is little argument that canine and feline acupuncture is a modern Western invention… Both detractors and proponents should regard the current practice as a distinctly modern adaptation with unclear lineage to antiquity, even more so when examining small animal treatment systems.” Nevertheless, the UF acupuncture document clearly states, “Veterinary acupuncture has been practiced in China for at least 2,000 years.”

The same professor acknowledges the mystical and religious foundations of modern TCVM and acupuncture, yet he seems untroubled by teaching and employing these methods as if they had meaning, based apparently on personal positive experiences and the dubious and irrelevant tu quoque fallacy that because evidence-based medicine is imperfect anything goes:

The Chinese approach to human disease was historically rooted in changing philosophies, including Daoist, Naturalist, and Confucian traditions. The relative popularity of these philosophies influenced the emphasis on certain Chinese medical concepts, such as the system of opposites (ie, yin-yang theory) and the natural relationships of organs in Five Element theory.

Veterinary medicine has followed the homogenization of Chinese medicine for humans and is now an adapted and standardized mixture of the Five Element, yin-yang, and bian zheng systems.

Modern transpositional meridians, or channels, form the basis for veterinary acupoint nomenclature but remain controversial because of associations with Five Element theory and traditional concepts of Qi (broadly defined as energy).

… detractors should acknowledge the widespread deficits in evidence-based medicine throughout the veterinary profession.

He also says, “Proponents of acupuncture should accept limitations in the technique’s application…” Yet it is puzzling what he means by “accepting limitations in the technique’s application” since his own department’s explanation of acupuncture for clients states, “There are no specific diseases that cannot be treated with acupuncture.”

Most of the academics involved in this sort of integrative medicine appear to honestly believe in the central role of science for evaluating medical therapies, though they often appear not to understand the philosophy or methods of science very well. They often contribute valuable and legitimate scientific knowledge to the profession in other areas. I don’t doubt that their desire to apply science and evidence-based medicine to alternative therapies is genuine.

However, I do doubt their willingness to accept the invalidation of the methods they believe in and champion. It is rare for high quality scientific research to demonstrate an alternative therapy is truly effective unless there is a plausible mechanism consistent with a scientific understanding of nature to begin with. Most of the numerous studies sponsored by organizations like the National Center for Complementary and Alternative Medicine (NCCAM) find no benefit to patients. This would be a perfectly appropriate and legitimate application of science to these therapies if it led to the abandonment of therapies that are ineffective, and an improved awareness of the importance of establishing a plausible hypothesis before spending limited resources on clinical research.

The reality, unfortunately, is that the rare positive studies are trumpeted as vindications, even when they are unreliable, and the many negative studies are ignored or rationalized away. When science is put to the service of advocacy for unscientific beliefs, the result is rarely good science or an improved understanding of nature. Given the obvious anti-science views of the leadership of the AHVMF and the Chi Institute, it seems likely that the work they sponsor will be much like that supported by CAM advocates in human medicine—unlikely to validate many therapies and even more unlikely to lead to anyone giving up on therapies that fail to be validated scientifically.

So while I approve of legitimate scientific inquiry into any therapies that could possibly be beneficial, in which I include many herbal therapies, some manual therapies and even possibly acupuncture (though there, the light of hope is dim and growing dimmer), I fear that UF and other veterinary institutions will be influenced by the financial and ideological support of groups like the AHVMF and the Chi Institute with agenda’s that are incompatible with such legitimate scientific inquiry. Time will tell, but the lesson of such integrative medicine in the human medical field does not encourage hope that veterinary medicine will become more effective or more evidence-based by following this path.

Posted in Acupuncture | 3 Comments

Anxitane (l-theanine) for Anxiety in Dogs

Introduction
I was recently asked to look into the evidence concerning a potential therapy for anxiety in dogs, a supplement called Anxitane. It is always challenging to evaluate the effects of any therapy for anxiety in any species. Anxiety is a subjective and highly variable state, and how it is triggered, experienced, and manifested is unpredictable. An objective, consistent measure of anxiety is very difficult to find.

In humans, a researcher can ask people to report their level of anxiety, but this can be problematic since many factors besides the treatment being studied can affect the feeling and how the patients report it. In dogs, of course we cannot directly ask them to report their level of anxiety. We can try to correlate specific behaviors or physiological measurements with what we believe to be anxiety or anxiety-inducing experiences, but there is still a great deal of subjectivity and uncertainty to this. And, as is the case for pain and other subjective outcomes, there are many factors besides the treatment being studied which can influence how humans evaluate the effect on the dogs being studied, the so-called caregiver placebo effect.

Nevertheless, it dogs do appear to suffer from states that seem equivalent in many ways to what humans would label anxiety, and since their brains are similar in many important ways to ours, it is reasonable to expect their internal states and the external factors that can affect them will be similar in some ways. So treatments for anxiety in dogs are appropriate to study even if we cannot perfectly delineate the problem we are treating or the outcomes we seek to measure.

What Is It?
Anxitane is a product containing an amino acid, L-theanine, derived from green tea. Amino acids of various kinds have important effects as neurotransmitters in the brain, are supplements with amino acids in them may have important effects of brain chemistry and hence emotional states. L-theanine is structurally very similar to the amino acid neurotransmitter glutamate, and may exert effects in the brain by stimulating glutamate receptors.

Does It Work?
There have been some studies suggesting l-theanine may reduce anxiety in humans. However, the consensus appears to be that there is not yet sufficient evidence to show this amino acid has a meaningful or consistent effect on anxiety in people. A recent systematic review concluded that there were effects seen in some studies but not in others, and no general recommendation could be made based on the existing evidence:

For state anxiety ratings (STAI-S), meta-analysis on the effects of 200 mg of L-theanine at 40–50 minutes post dose did not reveal any significant effects on anxiety.

[Other study] findings provide preliminary evidence to suggest that L-theanine may ameliorate the effects of acute stress, yet may not noticeably reduce baseline levels of anxiety. However, it is important to note that this sample included a certain proportion of high anxiety-prone individuals. While it would not be expected that these participants would respond differentially to placebo and L-theanine, conclusions derived from such a sample should be viewed with caution.

Similarly, the WebMD review of the evidence states that, “Preliminary evidence suggests that taking theanine might make unstressed people feel more tranquil. But theanine doesn’t seem to have this effect on people who are anxious to start with.”

There have been two published studies in dogs evaluating l-theanine for anxiety. The first was a preliminary study in 12 dogs with noise phobia.

V. Bertesell1; M. Michelazzi. Use of L-theanine tablets (Anxitane) and behaviour modification for treatment of phobias in dog: A preliminary study. J Vet Behav. May-June 2007;2(3):101.

The results were not evaluated statistically, because there were too few subjects, and the report does not report if subjects were randomly assigned to groups, if investigators evaluating the response were blinded, or other important indicators of risk of bias and error. The authors indicate there was some apparent effect, but it isn’t clear if it was a true effect or clinically significant:

This is a preliminary study and the number of the subjects is too small to have significant results…Comparison of groups A [Anxitane and behavioral therapy] and B[behavioral therapy alone] showed an improvement in the phobic behavioral manifestations with respect to the dogs’ responses and severity.

The second study compared treatment with Anxitane and a placebo in two groups of 5 laboratory beagles judged subjectively to be afraid of humans.

Joseph A. Araujo; Christina de Rivera; Jennifer L. Ethier; Gary M. Landsberg; Sagi Denenberg; Stephanie Arnold; Norton W. Milgram. ANXITANE® tablets reduce fear of human beings in a laboratory model of anxiety-related behavior. J Vet Behav. September 2010;5(5):268-275.

Dogs were randomly assigned to the two groups, tested before administration of the treatment, and retested after 8 weeks of treatment. The testing consisted of putting the dogs in a field, with and without a human who did not intentionally interact with them, and then measuring the dogs’ behaviors and the extent to which they approached the person when there was a human in the field. The study also evaluated overall level of activity, using activity monitors attached to the dogs, and monitored for any apparent adverse effects.

At baseline, the only difference was that the dogs in the treatment group were more active overall than the dogs in the placebo group. After the 8-week treatment period, there were no differences between the groups in the amount of change in activity level or on the dogs’ behaviors alone in the field. The dogs in the treatment group spent more time near the human and interacted with the human more than the dogs in the placebo group. No obvious adverse effects were seen.

There are a number of limitations to this study. The most obvious are the small number of dogs (5 in each group), and the artificial nature of the study population and the tests. Whether or not this result is applicable to pet dogs with anxiety disorders in the real world is an open question. There were also some other methodological concerns. There were statistically significant differences in three of four measures compared, however the p-value for one of these was barely significant (P=0.0472), and it is not clear if any correction was made for multiple comparisons. And the measures of time spent near the human and interaction with the human actually decreased for both groups after treatment on three out of four measures. It is puzzling why a decrease in fear of humans would lead to less interaction with the human compared to baseline. Finally, it is worth noting that the study was funded by the manufacturer of Anxitane.

Is It Safe?
There is very little evidence concerning the effects of l-theanine in general, however there is no obvious indication of risks in the studies that have been conducted. As an amino acid, the substance is likely to be safe at doses similar to what would be consumed in food, though there could potentially be side effects at much higher doses.

Bottom Line
The theoretical reasoning behind the potential value of l-theanine for treatment of anxiety in dogs is plausible, which means it could work. The research in humans shows some weak evidence for a possible benefit, but the evidence is not sufficient to allow firm conclusions. Likewise, the research evidence in dogs is limited and weak, and it is not possible to say with any confidence whether or not l-theanine has a meaningful benefit for dogs with anxiety. It could work, but at this point we don’t know if it actually does.

Since the product is likely safe, there is little risk in trying it in dogs with anxiety. However, without stronger evidence for a benefit, it should not be viewed as a substitute for therapies with better evidence of efficacy.

Posted in Herbs and Supplements | 1 Comment

Evidence Update: Azodyl for Chronic Kidney Disease in Dogs

One of the products I have kept track of over the years is Azodyl, a probiotic reported to be useful in treating kidney disease in dogs and cats. Though the company has reported positive results in laboratory studies involving rats, cats, and pigs, the independent studies so far reported in dogs and cats have not found any real-world benefits. Apparently last summer another study was presented at the ACVIM Forum, a conference for veterinary internal medicine specialists.

Kanakubo; S. Ross; H. Finke; J. Kirby; S. Nalor; C. Stafford; L.D. Cowgill. Influence of AzodylTM on Urea and Water Metabolism in Uremic Dogs. ACVIM Forum 2013, June 12-15,. Seattle, WA.28970

The study was not a clinical trial but a laboratory study of a small number of dogs (4) undergoing dialysis for treatment of kidney disease. The investigators evaluated the effects of Azodyl, given at two different doses over 1-2 months of time, by comparing various laboratory tests for measuring kidney function and the processing of nitrogen from protein in the diet in the same dogs before and after giving the probiotic. The study was partially funded by the manufacturer of Azodyl.

The investigators concluded that there were no changes in any of the measured values when these dogs were put on Azodyl. However, the dogs did appear to gain weight from fluid, suggesting that perhaps the product influenced water consumption or absorption.

 The results of this short-term study demonstrated:

  • AzodylTM had no significant or beneficial effect on pre-dialysis BUN in dialysis-dependent dogs.
  • AzodylTM had no significant effect on single treatment or weekly time-average urea, TACurea; urea appearance rate, Ga; or the whole-body urea clearance, Curea.
  • AzodylTM administration produced no demonstrable effect on the intestinal clearance of urea, Cint.
  • AzodylTM administration was associated with a positive increase in total body water requiring increased dialytic removal to maintain dry-weight.
  • Despite manufacturer’s suggestion, AzodylTM did not influence short-term azotemia or nitrogen metabolism in this CKD cohort.
  • AzodyTM was associated with a positive fluid balance in these dogs.
  • These results were unable to support the potential for AzodylTM to facilitate ‘Enteral Dialysis’ in dogs with CKD undergoing hemodialysis

 

This is a pretty small and unusual population of dogs compared to those who will normally be treated with Azodyl in routine clinical practice, so it does not determine whether or not the product is clinically useful in more typical cases. However, it does undermine some of the theoretical rationale for why Azodyl might be useful in chronic kidney disease in dogs.

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What is “Integrative Oncology” & is it Good for Patients?

I’ve written about so-called “integrative medicine” in the past, and my conclusion was that it is largely a Trojan horse intended to exempt certain alternative therapies from rigorous scientific scrutiny and gain mainstream acceptance without appropriate evidence of safety and efficacy. This is accomplished partly by muddying the waters of what “alternative” and conventional therapies are, claiming certain perfectly ordinary science-based practices such as exercise and a healthy diet are “alternative,” and then using the good data for these to imply that all integrative therapies are equally legitimate. Integrative medicine is largely a marketing concept designed to gradually erode skepticism of unproven and implausible methods without actually demonstrating their value scientifically.

There is an interesting and thoughtful discussion of the specific variety of this phenomenon known as “integrative oncology,” in the current issue of Nature (free with registration). Since the same kinds of language and arguments presented for integrative oncology in humans crop up in veterinary oncology fairly often, this article seems quite pertinent to veterinary medicine.

I encourage anyone interested to read the full article, but here are a few selections:

Integrative oncology is often touted as being useful for relieving symptoms, rather than as a primary treatment for the actual cancer. Unfortunately, a closer examination of many CAM modalities indicates that the vast majority of them rest on principles that, from a strictly basic science standpoint, range from highly implausible to virtually impossible — some rest on principles whose precepts violate well-established laws of physics and chemistry and/or are rooted in pre-scientific vitalism (such as homeopathy and energy medicine…In CAM, as in science-based medicine, prior plausibility is no guarantee of positive results, but prior probabilities that are as close to zero as those of homeopathy are a good guarantee of negative results.

To the extent that conventional medicine might underemphasize non-pharmaceutical health-promoting activities, such as lifestyle interventions and nutrition, integrative oncology could be argued to be useful in its reintroduction of an emphasis on consuming a balanced diet, exercising, and doing things that promote general wellness, some of which could conceivably at least improve the quality of life in cancer patients, if not their overall chances of surviving their disease. However, this reintroduction is not without a price, and it is questionable whether the claimed benefits are worth this price.

Integrative oncology integrates unscientific practices into science-based medicine, and, worse, the non-biologically based subdivisions of CAM is so pervasive, so embedded in the very fabric of integrative oncology, that it opens the door to clinical trials of dubious efficacy and the wasting of time and resources.

…in its current form at least, integrative medicine integrates a great deal of pseudoscience and bad science with science-based oncology.
It does not need to be this way…practicing truly holistic oncology does not require rejecting science and embracing pseudoscience. It is possible to introduce scientifically supportable elements of CAM, such as certain dietary and lifestyle interventions, into oncology as science- and evidence-based supportive modalities There should be no such thing as alternative or integrative medicine. There should only be medicine with strong evidence supporting efficacy and safety. Unfortunately, most of what is being ‘integrated’ with science-based medicine in integrative oncology is either unproven or has been proven not to work. Patients with cancer deserve better.

Posted in General | 6 Comments

Latest Review of Evidence for Vitamin D & Calcium Supplements

I have reviewed the complex and inconsistent evidence concerning the potential risks and benefits of vitamin supplements here, and concluded that most of the common claims for health benefits are unjustified. I recently discussed an example of this sort of unjustified claims, a veterinarian promoting screening tests for blood levels of Vitamin D and recommending supplements for nearly all patients. Fortuitously, a new comprehensive review of the evidence regarding Vitamin D and Calcium supplementation has just been published, which illustrates the lack of real evidence for many of these sorts of claims.

Agency for Healthcare research & Quality, U.S. Department of Health & Human Services. Vitamin D and Calcium: A Systematic Review of Health Outcomes (Update). Evidence Report/Technology Assessment 217. AHRQ Publication No. 14-E004-EF. September 2014

Not surprisingly, the review concludes that the evidence is insufficient to support most of the claims made for supplements of these substances.

In solid agreement with the findings of the original report, the majority of the findings concerning vitamin D, alone or in combination with calcium, on the health outcomes of interest were inconsistent. Associations observed in prospective cohort and nested case-control studies were inconsistent, or when consistent, were rarely supported by the results of randomized controlled trials. Clear dose-response relationships between intakes of vitamin D and health outcomes were rarely observed. Although a large number of new studies (and longer followups to older studies) were identified, particularly for cardiovascular outcomes, all-cause mortality, several types of cancer, and intermediate outcomes for bone health, no firm conclusions can be drawn…it is difficult to make any substantive statements on the basis of the available evidence concerning the association of either serum 25(OH)D concentration, vitamin D supplementation, calcium intake, or the combination of both nutrients, with the various health outcomes because most of the findings were inconsistent.

It is particularly important to note that the evidence is often inconsistent, and that uncontrolled study designs often lead to conclusions that don’t turn out to be true when examined in controlled trials. The value of any single study is low, and the balance of the evidence must be evaluated to draw meaningful conclusions.

Regarding cancer specifically, the review did not find consistent evidence that low Vitamin D levels predispose to cancer nor that supplementation is protective.

Synopsis

No qualified systematic reviews have evaluated relationships between vitamin D and total cancer incidence or mortality. No new RCTs were identified for the current report that addressed the effect of vitamin D or vitamin D combined with calcium on the risk for total cancer or cancer mortality. One cohort study found no association between total (all-cause) cancer and 25(OH)D concentrations (rated A), whereas a second cohort study observed an association in men but not in women (rated B). Ten cohort studies and one nested case control study addressed the association of serum 25(OH)D concentrations and cancer mortality. Five of the cohort studies (1 rated A, 4 rated B) observed no association of serum 25(OH)D concentration with total cancer mortality. Three cohort studies and the nested case control study observed a trend toward increased risk with decreased serum 25(OH)D (all rated B). One analysis using updated NHANES III data (rated B) observed a trend toward increasing risk for death with increasing serum 25(OH)D among men at higher latitudes whose blood was drawn in summer but the reverse in women. One cohort study observed a U-shaped association of increasing mortality with both low and high serum 25(OH)D.

One RCT in the original report showed no effect of combined vitamin D3 (1000 IU/d) and calcium (~1500 mg/d) supplementation versus calcium supplementation (~1500 mg/d) alone on the risk of total cancer in healthy postmenopausal women (>55 years old) living in Nebraska (latitude 41°N). Another RCT also found no difference in total cancer mortality or incidence between supplemental vitamin D3 (100,000 IU every 4 months) and placebo in elderly (71+ years old) men and women living in the United Kingdom (latitude 52° N). Both RCTs were rated B quality.

Analyses using NHANES III data (general adult populations living in the United States) showed no significant association between baseline 25(OH)D concentrations and total cancer mortality.

As always, this review doesn’t preclude the possibility that Vitamin D and Calcium may be associated with the risk for some cancers in some populations. But it does expose the lack of real support for the often-heard claims about these vitamins and cancer.

 

Posted in Herbs and Supplements | 3 Comments

Choosing Wisely-The Video

Here is some good advice about overdiagnosis and overtreatment–with a beat!! :-)

Posted in Humor | 6 Comments

Is There a Blood Test for Cancer in Dogs & Cats?

I am often asked by clients if there is a blood test that can tell if their apparently healthy pet has cancer. Obviously, “cancer” is a scary word, and many of the various diseases given that label are difficult to diagnose and treat. Many people have had personal experiences of a family member, human or non-human, developing cancer, and they are understandably looking for a way to identify such disease as early as possible, with the hope this will make it easy to control or even cure. Unfortunately, like most things in medicine, the reality is far more complex and uncertain than a simple blood test that will identify a hidden cancer in time to treat it.

Cancers differ in their basic biology and behavior, so each requires a different approach to diagnosis. Leukemia may show up as an abnormal number of white blood cells in a complete blood test, but breast cancer will not. High calcium levels have been associated with several cancers, but these range from lymphoma, a common white blood cell cancer spread throughout the body, to anal gland carcinoma, an uncommon tumor that shows up in that particular location only. The variety among cancers make any single test for most or all types very unlikely.

A Bit About Screening Tests

It is also important to understand a bit about the difference between testing for a disease when there is some symptom or other reason to suspect it is present (diagnosis) and testing for the presence of disease in apparently healthy patients (screening). The chances of getting the right answer from a specific test for a particular cancer are much higher when the patient has typical symptoms or other test results that suggest the presence of that cancer. All tests are imperfect, and all give false positive or negative results sometimes. If large numbers of healthy patients are tested, most of whom don’t have the disease, then a lot of the positive tests will turn out to be wrong, but most of the negatives will be true. This is the case even for very, very good tests.

The best way to illustrate this is—brace yourself—with a little math.

Say you have 10,000 people to test, none of whom have any symptoms or problems to suggest they have cancer. However, 200 of them have the cancer you are testing for (2%), while 9,800 do not. You have a test that is about as close to perfect as you can get–98% sensitive and 98% specific. That means that if you have 100 patients with the disease, 98 will test positive and 2 will test negative even though they have it (sensitivity). It also means that if you test 100 patients who don’t have the disease, 98 will test negative and 2 will test positive even though they don’t have it (specificity).

So we test all 10,000. Here are the results we will get:

True positive (test positive and have cancer)- 196

True negative (test negative and don’t have cancer)-9,604

False positive (test positive but don’t have cancer)-196

False negative (test negative but actually have cancer)-4

So we found most of the cases of cancer and we re-assured most of the healthy people. BUT, we also told 4 people with cancer that they were fine. And we told 196 healthy people they had a terrible disease. Did we do more good than harm?

Well, it depends on lots of other things. If early detection leads to more effective treatment and better survival, then at least the true positive patients will benefit. However, those we missed will think all is well and may ignore future symptoms or test results that might actually help them get treatment.

On the other hand, if early detection with this test doesn’t lead to better treatments and outcomes, then all we’ve done is give people bad news which they can’t do anything about even if it’s true. Screening doesn’t help anybody if there is nothing we can do about the disease at the point at which we detect it.

It is also likely that those who got a positive test will have to undergo uncomfortable and expensive testing and maybe even cancer treatment even if they don’t actually have cancer (which, remember, is almost 200 of our patients). We have actively harmed these folks with our test.

There has been a lot of controversy in human medicine recently about screening tests for cancer that were once widely recommended. PSA testing for prostate cancer, for example, turns out to cause a lot of harm. Positive test results often result in expensive and uncomfortable treatment with some serious side effects, and yet it appears not to reliably improve long-term outcomes. In other words, men who get tested will often suffer more harm from treatment without actually living any longer than men who did not get early detection with this test. While the test still has some appropriate uses, widespread screening of men with no symptoms of disease turns out not to be a very good idea. Similar concerns have led to changes in screening for breast cancer and to a growing recognition in human medicine that screening tests of apparently healthy people lead to significant overdiagnosis and harm in many cases.

The situation is a bit different in veterinary medicine. For one thing, there are few blood tests that have been tested at all for the ability to detect cancer before symptoms develop. And for most cancers, there is no research evidence that such early detection would allow us to better treat or even cure such cancers if we could find them. While it is often assumed that the earlier we detect cancer the more we can do about it, this has not been proven in dogs and cats and has actually turned out not to be surprisingly often in humans.

But My Vet Said There Was a Good Screening Test for Cancer

Unfortunately, there are still some veterinarians who will recommend, and sell you, cancer screening blood tests for your pets with a good deal more confidence in their benefits than is justified. A recent article, written by an alternative medicine practitioner I’ve written about before, makes strong claims for his ability to use a couple of blood tests, C-reactive protein, thymidine kinase, and Vitamin D3 levels, to detect cancer or precancerous conditions before your pet is sick and then treat them effectively.

A series of simple, new, inexpensive blood tests bundled into a diagnostic panel now allows doctors to detect cancer and other serious problems before they develop in your dog or cat…These new blood tests can determine your companion’s risk of developing this dreaded disease, and even detect it in its earliest stages.

While these new cancer tests are very helpful for determining the status of your animal’s health before he becomes ill, they are also helpful for monitoring dogs and cats that already have cancer. For those already diagnosed with the disease, monitoring [these] levels helps veterinarians make decisions about changing treatment and to predict when/if the cancer may return and when the animal may come out of remission.

This cancer testing is very cost effective. In our office, we charge under $200 for the entire three-test profile, making it very inexpensive considering the wealth of information we receive from it. Additionally, this profile is the easiest and least expensive way to screen dogs and cats for cancer and other serious inflammatory diseases. There are really no disadvantages to having this testing done.

These claims raise a number of important questions: 1. Can these tests really detect cancer before your pet has symptoms? 2. What should we do if we have a positive test result? 3. Does testing, and whatever we do next, help prevent illness or prolong health and life? 4. Can this testing do any harm?

Can these Tests Really Detect Cancer Before My Pet Gets Sick?

The short answer is, we don’t know. It is important to remember that none of these tests is routinely used or recommended for cancer screening of healthy people or animals by doctors or organizations specializing in cancer detection and treatment. This kind of screening is not a widely accepted practice. Nevertheless, there is research evidence looking at the possible value of these tests for cancer screening. I will offer a brief summary of the evidence and try to answer our four questions.

Thymidine kinase (TK1)- This is a substance which is produced by dividing cells. Since cancer cells typically divide more rapidly than healthy cells, it tends to be produced in greater amounts when there are cancer cells present. This is particularly true for cancers of blood cells, such as lymphoma and leukemia. TK1 it is less consistently elevated in patients with other kinds of tumors. To a lesser extent, elevated TK1 levels have also been associated with viral infections and inflammatory conditions as well as cancer.

There is a lot of evidence to suggest that TK1 levels are higher in dogs with known cancer than in healthy dogs, especially when the cancer is lymphoma or leukemia. Most studies compare health animals with those already diagnosed with cancer by other methods, and they usually find higher TK1 levels in the cancer group. These are not, however, animals with occult cancer, that is cancer that hasn’t caused any symptoms or been diagnosed yet. Whether TK1 levels are consistently higher in dogs who have cancer but not symptoms hasn’t been clearly demonstrated. The TK1 levels of healthy dogs, dogs with cancer, and dogs with other diseases overlap quite a bit. There are even some studies in which as many as half of the dogs with known lymphoma had normal TK1 levels. So there are certainly not clear absolute differences to distinguish these groups.

While it has some potential, TK1 testing is not clearly a useful diagnostic or monitoring tool for dogs with most cancers, much less a screening tool for dogs who might or might not have cancer. As usual, there is even less data related to cats, though there are some suggesting TK1 might behave similarly in this species.

C-Reactive Protein (CRP)-

CRP is a protein associated with inflammation. Inflammation can be caused by many different things, such as infection, autoimmune disease, and of course cancer. CRP is quite sensitive to inflammation, but it does nothing to help distinguish the cause. In dogs, CRP is elevated in at least some kinds of cancer, and the values are generally higher than in dogs without cancer. However, there is significant overlap between these groups, so some dogs with cancer will have normal CRP and some without will have elevated CRP. Interestingly, dogs with lymphoma who are in remission (no illness or detectable tumor but microscopic cancer still present somewhere) generally have lower CRP than dogs with active lymphoma. This means CRP could possibly be used to test for relapse of this cancer. However, dogs in remission are just like dogs without symptoms of cancer who we would be using a test like this to screen, so these data suggest we wouldn’t be able to find lymphomas with this test if there were no symptoms or obvious tumors.

Vitamin D-

Vitamin D, like all vitamins, has a number of essential functions in the body. It has been well known for decades how much vitamin D people (and dogs and cats) require to prevent symptoms of Vitamin D deficiency disease. However, it has been a bit of a fad for a while now to claim that even higher levels would have protective effects against a variety of diseases, including cancer.

This is based largely on a few studies which found that people with certain disease, including some kinds of cancer, tend to have lower Vitamin D levels than healthy people. However, additional research has failed to demonstrate that low levels cause these diseases or that supplements prevent them. People who are sick may have low Vitamin D levels as a symptom of their illness rather than as part of its cause. For the most part, testing for Vitamin D and supplementing to prevent cancer is not recommended in humans unless there are specific reasons to believe an individual patient is at risk for low Vitamin D levels (in other words, routine screening is not recommended).

There is not good evidence to suggest that subclinical Vitamin D deficiency is a real problem in dogs or cats either, or that supplementation beyond the levels currently used in commercial diets is of any benefit.

Veterinary Diagnosic Institute Cancer Tests-

Despite the fact that these tests are not used as general cancer screening aids in humans, and the lack of strong evidence to show they can reliably predict cancer in dogs and cats, there is a company selling these tests as a tool for cancer screening, as well as for cancer diagnosis and monitoring response to therapy. Apart from the general information for each test I’ve already discussed, the company has produced one clinical study to evaluate its screening test.

Selting KA, Sharp CR, Ringold R, Knouse J. Serum thymidine kinase 1 and C-reactive protein as biomarkers for screening clinically healthy dogs for occult disease. Vet Comp Oncol. 2013 Jul 16. doi: 10.1111/vco.12052. [Epub ahead of print]

This study involved collecting blood from about 360 dogs (German shepherds and golden retrievers) to test for CRP and TK1 and then following them for 6 months or more to see which developed cancer or died of some other disease. The dogs were not evaluated by a veterinarian as part of the study, and most health information was obtained from questionnaires completed by owners. This raises the possibility that some dogs may not have been properly classified or diagnosed, which might change the results and conclusions significantly.

As expected, over the short course of the study the incidence of cancer was pretty low, about 3%. This means 11 dogs developed some kind of cancer. Because CRP is not very specific for cancer but simply detects any inflammation, it was not used by itself to predict cancer development. However, the TK1 test tends to be more specific for cancer but not as sensitive as the CRP, so the authors looked at both the TK1 by itself and the combination of the two tests (called the neoplasia index or NI) to predict cancer development.

Sensitivity and specificity of a diagnostic test are always in opposition to one another. The more sensitive a test is (that is, the more actual cases of disease it finds), the less specific it is (that is, the more healthy patients will test positive for a disease they don’t have). This is true for any test, and the balance between the two numbers is related to what value of the test one uses as a cutoff. In this study, the authors followed the common practice of  analyzing their data with a variety of cutoffs to try and find the best balance between sensitivity and specificity for the test.

In the case of cancer screening for apparently healthy patients, there are dangers to both a low sensitivity and a low specificity. If the test is very sensitive but not very specific, then it will indicate a lot of healthy animals have cancer when they don’t. Apart from the worry this creates for their owners, there will be a lot of expensive, and sometimes uncomfortable or even dangerous, follow-up testing and possibly even unnecessary treatment for a disease that isn’t there. This is the danger of overdiagnosis.

On the other hand, if a test is very specific but not very sensitive, a lot of animals with cancer will show up as healthy on the test. This is a problem if early detection and treatment could lead to a better outcome, though as I mentioned earlier this has not generally been demonstrated for dogs and cats with cancer.

For TK1 alone, the best sensitivity achieved was 100%, meaning all dogs that developed cancer later had an abnormal test at that particular cutoff. However, when that level was used, the specificity was 0, meaning that everybody would test positive whether they had cancer or not. At the other end, the best specificity achieved was 98%, but at this level sensitivity was only 27%. Between these extremes, it was possible to get one or the other value around 80% with the opposite value about 70%. This is not a very good compromise for a test intended to be used in a population with a very low rate of cancer because there will be a lot of patients misclassified with regard to a very serious disease.

The authors expected, of course, the TK1 to be pretty specific (good at ruling out cases that don’t have cancer) but not very sensitive. This is why they combined it with the more sensitive CRP to try and improve the overall sensitivity without losing too much specificity. This combined neoplasia index had an optimal balance of sensitivity and specificity at 82% sensitivity and 91% specificity. In the case of a cancer screening test, it is probably better to favor specificity so you don’t do unnecessary tests and treatments on healthy animals. A lower sensitivity will miss some true cases of disease, but it isn’t clear yet that finding these cases earlier improves their outcome, and of course they will eventually develop symptoms that will lead to a diagnosis.

In the case of a screening test, which is intended to be used on a population which is mostly healthy and disease is rare (about 3% in this study, for example), there are a couple of numbers more useful than specificity and sensitivity. These are the positive predictive value (PPV) and the negative predictive value (NPV). The PPV is, essentially, the percentage of positive tests that are correct, that is the patient actually has the cancer the test says they have. The PPV for this test in this study was 22.5%. That means that when a patient has a positive test, only about 22% of the time is there actually a cancer there. That leads us to  the second question….

What Should I Do if my Pet Has a Positive Test?

The veterinarian promoting this test offers some hint of how he responds to positive results.

In my practice, animals with increased TK levels are supplemented with specific herbal remedies (Healthy Qi, CA Support, etc.) to support their immune systems. The blood is retested one month later. If TK levels are back to normal, no further testing is needed for four months. If TK levels continue to increase, then we must search further for the reason why it’s increasing. A persistent elevation of TK levels predicts the likelihood of cancer developing over the next six months.

So this doctor recommends responding to a positive test with the use of unproven, and untested, herbal products from the pre-scientific system of myths and metaphors known as Traditional Chinese Veterinary Medicine (TCVM). Given the implausible and unvalidated methods used in this system, the risks of untested and unregulated herbal supplements, and the fact that the concept of “boosting the immune system” is itself nonsense, this is certainly not a useful response. Of course, the plan proposed here also ignores the fact that values such as these vary with time for many reasons, and the fact that they might decrease when such remedies are used does not, of course actually mean the remedies are responsible, though that is undoubtedly the implication here.

I would like to be able to say that this approach is only that of this individual “holistic” veterinarian, and it does not necessarily imply that VDI has a similarly dubious and evidence-poor approach to the use of their products. However, among the informational materials VDI offers vets to help understand how to use this test is an article, entitled The Holistic View, by this same doctor. Clearly, the company is willing to endorse such dubious practices in the interest of marketing its products.

Simply following TK1 levels over time, if one chooses to measure them, may be a more reasonable strategy. Persistent elevations or increases over time are more likely to be meaningful than individual values. But instituting dubious treatment in response to an elevation is not rational. Neither is an extensive diagnostic workup looking for cancer. While the risks of diagnostic imaging, such as chest x-rays and abdominal ultrasounds, are low, these tests do have costs, they can find irrelevant abnormalities which would lead to unnecessary further testing and treatment, and they can generate false reassurance when they fail to find an abnormality. Effective use of such tests requires establishing a reasonable clinical index of suspicion which can help guide interpretation of the results and further actions.

This author makes similar recommendations for responding to elevated CRP levels, including the use of supplements of unproven or questionable value without a specific diagnosis or clear clinical purpose for making use of them.

In animals with elevated CRP or Hpt levels, specific nutritional supplements (antioxidants, fatty acids, etc.) are administered to reduce harmful inflammatory proteins. Diseases know to be associated with inflammation, such as dental disease, arthritis, and allergies, are diagnosed and treated appropriately to reduce inflammation in the body. The blood is retested in one month and CRP/Hpt levels should have returned to normal. If they haven’t, further investigation is undertaken.

And finally, the author makes a number of strong claims about the prevalence of Vitamin D deficiency and the need for supplementation that are not supported by real evidence or accepted by veterinary nutrition specialists.

While pet food is formulated with enough vitamin D3 to prevent deficiency disease (rickets), the levels are too low for maximum health. Testing shows most dogs have blood levels considered insufficient for optimal health, and would benefit from supplementation. Once the vitamin D3 test results are available, supplementation is given with the goal of shooting for a blood level of 100 mg/ml (in studies, animals with cancers tended to have vitamin D3 blood levels lower than 100.) Additional testing is done to confirm if the prescribed amount of vitamin D3, typically given once daily with food, is enough to reach the recommended blood level.

While there is certainly evidence that dogs with cancers, and other diseases, often have lower levels of Vitamin D than healthy dogs, as in humans it has not yet been clearly shown that the low levels increase the risk of developing disease or that supplementation prevents it. The specific number this author recommends as a target comes from a single study of dogs with a particular kind of cancer. And Vitamin D supplementation has risks as well, so recommending it based on inadequate data is not appropriate or helpful.

When screening tests of unproven value is recommended, and all abnormal results are taken as an indication to prescribe (i.e. sell) supplements that also have unclear value, it is difficult not to see profit as a significant motive in the marketing of this test. And while I don’t doubt this individual believes he is finding, and then treating or preventing cancer with this approach, this does not eliminate the potential influence of the obvious profit potential in this approach, nor excuse the lack of concern for the very weak evidence behind the practice.

A more evidence-based answer to the question of how to respond to a positive test result simply isn’t available, which is one of the major reasons why this sort of testing is not widely recommended. Until it is clear that the test consistently identifies real disease at a stage where it is both otherwise undetectable and can be more effectively treated, the testing and the diagnostic or therapeutic followup is based on little more than speculation or intuition, not sound, science-based medicine. This is also the answer to our third question….

Will Testing & the Followup Prevent Illness or Prolong Life?

The answer, unfortunately, is no one knows. The current evidence suggests some of these tests could lead to more effective detection and treatment of some cancers. However, as I mentioned earlier, this has not yet been proven to actually be true for humans or veterinary patients. The majority of promising ideas in medicine fail to fulfil their promise, which is why thorough scientific research is vital. Leaping on the bandwagon too early might occasionally work out well, but the odds are far better that it will lead to taking useless or even harmful actions that later evidence clearly shows we would be better off not having taken. If this particular testing strategy does turn out to work well for at least some patients, the folks promoting it will naturally look like prescient geniuses. If, as is more likely, it turns out to be less useful than hoped or even worthless or harmful, most people will probably not notice as we will likely move right on to the next promising idea. But a careful review of medical history suggests that we could make much better decisions, for ourselves and our pets, if we waited until the evidence was a lot stronger. After all, we are talking about testing healthy animals with no signs of disease! How much should we really put them through in an effort to prevent diseases they may not get using a test and therapies we don’t know actually work? Let’s not forget our last question…

Can These Tests Do Any Harm?

As I’ve already mentioned, overdiagnosis is a real, and serious, risk. The data shows that the PPV for this test, the proportion of positive results that are actually true, is quite low. So we are going to identify a lot of animals as having a disease they don’t have. If we put these animals through a lot of expensive diagnostic tests or, even worse, subject them to untested treatments as suggested by some proponents of this screening test, then we will generate a great deal of unnecessary stress for pets and their owners and unnecessary expense for some clients, and we may even harm some of the pets we are trying to help.

Of course, we will certainly detect at least some animals who actually do have cancer. Isn’t this a good thing, and doesn’t this balance the possible expense and harm we might do? Unfortunately, we don’t really know the answer to this either. Since we can’t be sure that detecting these cases earlier actually helps them, there is no way to balance that against the costs and risks of the testing.

Bottom Line

Screening tests, which try to identify hidden disease in apparently healthy animals, can sometimes be beneficial. If these tests are sufficiently accurate, and if we have truly useful treatments to offer the cases we find, then we can use such screening to reduce disease and suffering. However, at the moment there is no such screening blood test for cancer in dogs and cats.

The specific tests suggested here, thymidine kinase, C-reactive protein, and Vitamin D, do have some potential value in testing for cancer and monitoring cancer treatment. The evidence, however, is very preliminary and does not clearly tell us that these tests, alone or in combination, are sufficiently accurate to find most hidden cancers and not misidentify too many healthy animals as having cancer. Much more research needs to be done before these tests can be recommended as part of soundly scientific and evidence-based medicine.

And there is little evidence that if we had such a test we could actually help the pets with cancer we identified live longer or healthier lives. In addition to working on developing good screening tests for cancer in dogs and cats, we will need to find out which treatments, if any, can help these pets to live longer and stay healthier once we find them. Given unproven herbal remedies and supplements to these animals, even if the tests showing they have hidden disease are correct, does not benefit them and may do harm.

It is natural to want a clear, simply way to reassure ourselves our pets are healthy, and to want effective treatments to give them if we find they have cancer even though they appear healthy. However, taking the best care possible of our animal companions does not mean subjecting them to testing which is unreliable and therapies which aren’t proven to be safe and effective. Good preventative health care means scientific, evidence-based healthcare, not chasing after comforting promises without real evidence.

The best strategy for preventing disease in our pets is to feed them nutritionally complete diets, maintain them at a healthy, lean body condition, keep up with appropriate preventative care for infectious diseases and parasites, and provide them with appropriate socialization and training, physical and mental exercise, and love. While less dramatic in some ways that blood tests, supplements, and other kinds of constant tinkering with their physiology, this is still the best preventative health care we can give our pets.

 Bibliography

There are many basic science articles investigating TK!, CRP, and Vitamin D in dogs and cats (mostly dogs). This is intended as a sample of the literature to illustrate the state of the existing evidence. There have not yet been systematic reviews of these tests and compounds for companion animals, but plenty of other studies are indexed on PubMed.

1. Vet J. 2013 Sep;197(3):854-60. doi: 10.1016/j.tvjl.2013.05.036. Epub 2013 Jul 4.

High levels of inactive thymidine kinase 1 polypeptide detected in sera from dogs
with solid tumours by immunoaffinity methods: implications for in vitro
diagnostics.

Kiran Kumar J(1), Sharif H, Westberg S, von Euler H, Eriksson S.

Determination of serum thymidine kinase 1 (STK1) activity has been used as a
proliferation marker for neoplastic diseases in both human and veterinary
medicine. The purpose of this study was to determine STK1 activity and enzyme
levels in different dog tumours. Serum samples from three dogs with leukaemia,
five with lymphoma, 21 with solid tumours and 18 healthy dogs were analyzed for
STK1 activity, using an optimized [(3)H]-deoxythymidine (dThd) phosphorylation
assay, and for STK1 protein levels using an immunoaffinity/western blot assay.
STK1 activity in dogs with haematological tumours was significantly higher than
in the solid tumour and healthy dog groups (mean ± standard deviation [SD] = 65 ±
79, 1.1 ± 0.5, and 1.0 ± 0.4 pmol/min/mL, respectively). Serum samples were
analyzed after immunoaffinity isolation by western blot and the TK1 26 kDa band
intensities quantified revealing that concentrations were significantly higher in
dogs with haematological tumours and solid tumours compared to healthy dogs (mean
± SD=33 ± 12, 30 ± 13, and 10 ± 5 ng/mL, respectively). Pre-incubation with the
reducing agent dithioerythritol (DTE) showed a decrease in STK1 activity and
protein levels in most samples, but an increase of about 20% in sera from healthy
dogs and from those with haematological malignancies. Compared to animals with
solid tumours, the specific STK1 activity (nmol [(3)H]-deoxythymidine
monophosphate (dTMP)/min/mg of TK1 protein of 26 kDa) was 30-fold higher in
haematological malignancies and 2.5-fold higher in healthy dogs, respectively.
The results demonstrate that there is a large fraction of inactive TK1 protein,
particularly in sera from dogs with solid tumours. The findings are important in
the use of STK1 as a biomarker.
2. Vet Comp Oncol. 2013 Jul 16. doi: 10.1111/vco.12052. [Epub ahead of print]

Serum thymidine kinase 1 and C-reactive protein as biomarkers for screening
clinically healthy dogs for occult disease.

Selting KA(1), Sharp CR, Ringold R, Knouse J.

Thymidine kinase (TK1) is a biomarker that correlates well with diagnosis and
prognosis in certain canine cancers. Canine C-reactive protein (cCRP) is a widely
accepted marker of inflammation correlated with increased risk and severity of
various diseases. We evaluated serum TK1 and cCRP concentrations in apparently
healthy dogs (n?=?360). All dogs were followed up for a minimum of 6?months by
health questionnaire. All dogs with cancer were identified using a proprietary
dual-biomarker algorithm [termed Neoplasia Index (NI)]. Specificity of positive
NI is 0.91 and high positive is 0.98. All-cause mortality was 20% in dogs with
elevated cCRP and 3% in dogs with low cCRP. The performance of serum TK1 and cCRP
as tools for screening for occult cancer is improved when evaluated together.
Serum TK1 and cCRP (unified in the NI) are useful in the screening of occult
canine cancer. cCRP is useful in screening for other serious diseases.

3. Vet Comp Oncol. 2013 Mar;11(1):1-13. doi: 10.1111/j.1476-5829.2011.00296.x. Epub
2011 Dec 8.

Thymidine kinase assay in canine lymphoma.

Elliott JW(1), Cripps P, Blackwood L.

The aim of the study was to evaluate if thymidine kinase (TK) correlated with
duration of first remission (DFR) or survival in dogs with lymphoma and if
initial TK levels correlated with stage and substage; and also to assess if TK
level at diagnosis correlated with immunophenotype. TK was assayed in 73 dogs
with treatment naïve lymphoma, then again after treatment; 47% had an initial TK
above the reference interval. Dogs with B-cell lymphoma had higher initial TK
activities than dogs with T-cell lymphoma. TK levels were not higher in dogs with
higher stage disease and TK activity prior to treatment was not associated with
DFR or survival. Where TK was elevated at diagnosis, it fell into the reference
range during remission. TK was normal in 53% dogs at diagnosis, which is higher
than previously reported. Further studies are warranted to assess the utility of
TK in dogs with lymphoma.

4. J Feline Med Surg. 2013 Feb;15(2):142-7. doi: 10.1177/1098612X12463928. Epub 2012
Oct 17.

Serum thymidine kinase activity in clinically healthy and diseased cats: a
potential biomarker for lymphoma.

Taylor SS(1), Dodkin S, Papasouliotis K, Evans H, Graham PA, Belshaw Z, Westberg
S, von Euler HP.

The thymidine kinases are enzymes that convert deoxythymidine to deoxythymidine
monophosphate and have a function in DNA synthesis. Rapidly proliferating cells
will have higher levels of thymidine kinase. Serum thymidine kinase activity
(sTK) is a useful tumour marker in humans and dogs, with utility as a prognostic
indicator in lymphoma. In the current study serum samples were collected from 49
clinically healthy cats, 33 with lymphoma, 55 with inflammatory disease and 34
with non-haematopoietic neoplasia (NHPN). sTK was measured using a radioenzyme
assay and a reference interval (1.96 × SD) was established from the clinically
healthy cats (<5.5 U/l). Mean sTK activity for healthy cats was 2.2 U/l (range
0.8-8.4, ± SD 1.7). Mean sTK activity for cats with lymphoma was 17.5 U/l (range
1.0-100.0 SD ± 27.4). Mean sTK activity for cats with NHPN was 4.2 U/l (range
1.0-45.0, SD ± 8.6). Mean sTK activity for the inflammatory group was 3.4 U/l
(range 1.0-19.6, SD 3.9). Cats with lymphoma had significantly higher sTK
activity than healthy cats or cats with inflammatory disease (P <0.0001) and cats
with NHPN (P <0.0002). sTK activity is a potentially useful biomarker for feline
lymphoma and further study is required to assess its utility as a prognostic
indicator.

5. Vet Comp Oncol. 2012 Dec;10(4):292-302. doi: 10.1111/j.1476-5829.2011.00298.x.
Epub 2011 Oct 20.

Elevated serum thymidine kinase activity in canine splenic hemangiosarcoma*.

Thamm DH(1), Kamstock DA, Sharp CR, Johnson SI, Mazzaferro E, Herold LV, Barnes
SM, Winkler K, Selting KA.

Thymidine kinase 1 (TK1) is a soluble biomarker associated with DNA synthesis.
This prospective study evaluated serum TK1 activity in dogs presenting with
hemoabdomen and a splenic mass. An ELISA using azidothymidine as a substrate was
used to evaluate TK1 activity. Sixty-two dogs with hemoabdomen and 15 normal
controls were studied. Serum TK1 activity was significantly higher in dogs with
hemangiosarcoma (HSA) than in normal dogs (mean ± SEM = 17.0 ± 5.0 and 2.01 ±
0.6, respectively), but not dogs with benign disease (mean ± SEM = 10.0 ± 3.3).
Using a cut-off of 6.55 U/L, TK activity demonstrated a sensitivity of 0.52,
specificity of 0.93, positive predictive value of 0.94 and negative predictive
value of 0.48 for distinguishing HSA versus normal. When interval thresholds of
<1.55 and >7.95 U/L were used together, diagnostic utility was increased. Serum
TK1 evaluation may help to discriminate between benign disease and HSA in dogs
with hemoabdomen and a splenic mass.
6. Int J Oncol. 2009 Feb;34(2):505-10.

Monitoring therapy in canine malignant lymphoma and leukemia with serum thymidine
kinase 1 activity–evaluation of a new, fully automated non-radiometric assay.

Von Euler HP(1), Rivera P, Aronsson AC, Bengtsson C, Hansson LO, Eriksson SK.
Thymidine kinase 1 (TK), which is involved in the synthesis of DNA precursors, is
only expressed in S-G2 cells. Serum TK levels correlate to the proliferative
activity of tumor disease. Determinations of TK levels have so far relied on
radio enzyme assay (REA) and experimental ELISA methods, which have limited the
clinical use of this biomarker, although recent studies in dogs with malignant
lymphoma (ML) demonstrate its wide potential. A non-radiometric method based on a
competitive immunoassay with specific anti-3′-azido-deoxythymidine monophosphate
(AZTMP) antibodies has been further developed into the fully automated Liaison TK
assay (DiaSorin). Sera from healthy dogs (n=30), and dogs with leukemia (LEUK)
(n=35), ML (n=84), non-hematological tumors (n=50), and inflammatory disease
(n=14) were tested using both methods. Lymphoma and LEUK samples were available
before and during chemotherapy. The coefficients of variation for the Liaison TK
assay in this study were 6.3 and 3.4% (low/high TK, respectively), and the
correlation between TK REA (X) and the Liaison TK assay (Y) was y=0.9203x+1.3854
(R2=0.9501). The TK1 levels measured during chemotherapy gave very clear
differences between dogs in complete remission and dogs out of remission. A
Tukey-Kramer analysis showed that all LEUKs and MLs out of remission differed
significantly from the other groups. The Liaison TK assay showed high precision,
high sensitivity and a good correlation to the TK REA. The Liaison TK assay
provides valuable clinical information in the treatment and management of canine
LEUK and ML, with a potential to be further validated in human trials.

7. J Vet Intern Med. 2004 Sep-Oct;18(5):696-702.

Serum thymidine kinase activity in dogs with malignant lymphoma: a potent marker
for prognosis and monitoring the disease.

von Euler H(1), Einarsson R, Olsson U, Lagerstedt AS, Eriksson S.

Serum thymidine kinase (sTK) activity was evaluated as a tumor marker for canine
malignant lymphoma (ML). The objective was to investigate if sTK, as in humans,
could be used as a prognostic marker for survival time in dogs with ML and if sTK
could identify early signs of progression of disease in treated dogs. Serum
samples from 52 dogs with ML were tested for initial TK activity. Samples from 21
normal dogs and 25 dogs with nonhematologic neoplasms were used for comparison.
Forty-four dogs with ML were treated. Serum TK activity was measured in treated
dogs before each treatment and every 4 weeks thereafter until relapse. Dogs with
ML had 2-180 times higher TK activity (TK 5-900 U/L) than normal dogs (TK <7 U/L)
based on the mean + 2 standard deviations. In the group of other neoplasms, only
2 dogs had a moderate increase (6.4 and 7.5 U/L) compared with the controls. Mean
sTK activities in the dogs with ML that had gone into complete remission (CR)
were not significantly different from activities in healthy controls (P = .68).
Mean sTK at least 3 weeks before and at the time of relapse was significantly
higher than activity measured at CR (P < .0001). Dogs with ML that initially had
sTK >30 U/L had significantly shorter survival times (P < .0001). Furthermore,
sTK activity reflected the clinical staging of ML. Measuring sTK can be used as a
powerful objective tumor marker for prognosis and for predicting relapse before
recurrence of clinically detectable disease in dogs with ML undergoing
chemotherapy.

8. J Vet Intern Med. 2004 Sep-Oct;18(5):595-6.

Serum thymidine kinase activity: an alternative to histologic markers of cellular
proliferation in canine lymphoma.

Madewell BR.

Thymidine kinase (TK) is a cellular enzyme which is involved in a ‘salvage
pathway’ of DNA synthesis. It is activated in the G1/S phase of the cell cycle,
and its activity has been shown to correlate with the proliferative activity of
tumor cells…. Clinical studies have reported high serum TK concentrations in a
variety of neoplasias. The majority of these studies concerned hematological
malignancies. TK seems to be a useful marker in non-Hodgkin’s lymphoma, where it
correlates with clinical staging and provides marked prognostic information on
(progression-free) survival.

PMID: 15515571  [PubMed - indexed for MEDLINE]
9. J Vet Med Sci. 1997 Oct;59(10):957-60.

Plasma thymidine kinase activity in dogs with lymphoma and leukemia.

Nakamura N(1), Momoi Y, Watari T, Yoshino T, Tsujimoto H, Hasegawa A.

Plasma thymidine kinase (TK) activity was evaluated as a plasma marker for canine
lymphoma and leukemia. A tentative “cut-off” value was set at 6.0 U/l as the
upper level of plasma TK based on the mean + 2SD of plasma TK activity in 13
clinically healthy dogs. The levels of plasma TK activity in all of the 20 dogs
with lymphoma and leukemia were higher than the cut-off value, whereas those in
dogs with lymphoma decreased in parallel with the reduction of the tumor mass
after chemotherapy. These findings suggested that estimation of plasma TK
activity can be used as a plasma marker for lymphoma and leukemia in the dog.

10. Vet Comp Oncol. 2014 Jul 8. doi: 10.1111/vco.12101. [Epub ahead of print]

Serum 25-hydroxyvitamin D concentrations in dogs – correlation with health and
cancer risk.

Selting KA(1), Sharp CR, Ringold R, Thamm DH, Backus R.

25-hydroxyvitamin D (25(OH)D) is important in bone health as well as many
diseases including cancer. Supplementation may increase responsiveness of cancer
cells to chemotherapy. Serum 25(OH)D, intact parathyroid hormone (iPTH) and
canine C-reactive protein (c-CRP) were measured in healthy dogs and dogs with
haemoabdomen. Regression analysis determined optimal 25(OH)D concentrations. In
healthy dogs (n = 282), mean iPTH concentrations correlated inversely (r(2) =
0.88, P < 0.001) to 25(OH)D concentrations. Variation in both iPTH and c-CRP
plateaued at 25(OH)D concentrations of 100-120 ng mL(-1) . Haemoabdomen dogs (n =
63, 43 malignant and 20 benign) had 25(OH)D concentrations ranging from 19.4 to
>150 ng mL(-1) . Relative risk of cancer increased with decreasing 25(OH)D
concentrations [RR = 3.9 for 25(OH)D below 40 ng mL(-1) (P = 0.0001)]. Serum
25(OH)D concentrations in dogs vary widely, and are influenced by dietary VitD
content. Serum vitD measurement can identify dogs for which supplementation may
improve health and response to cancer therapy.

11. Vet Parasitol. 2014 Jun 16;203(1-2):153-9. doi: 10.1016/j.vetpar.2014.02.001.
Epub 2014 Feb 25.

Serum acute phase protein concentrations in dogs with spirocercosis and their
association with esophageal neoplasia – a prospective cohort study.

Nivy R(1), Caldin M(2), Lavy E(1), Shaabon K(1), Segev G(1), Aroch I(3).

Spirocerca lupi, the dog esophageal worm, typically induces formation of
esophageal nodules, which may transform to sarcoma. Ante mortem discrimination
between benign and malignant esophageal masses is challenging. Serum acute phase
proteins (APPs) are utilized in diagnosis and prognosis of various canine
diseases as markers of inflammation. This study characterized serum APPs
concentrations in dogs with benign and malignant esophageal spirocercosis and
evaluated their accuracy in differentiating benign from malignant lesions.
Seventy-eight client-owned dogs with esophageal spirocercosis were included.
Serum C-reactive protein (CRP), haptoglobin, serum-amyloid A (SAA) and albumin
concentrations were measured upon diagnosis and follow-up visits, and compared
with healthy dogs, and between malignant and benign cases. Haptoglobin, CRP and
SAA concentrations were higher, and albumin concentration was lower (P<0.001 for
all) in infected dogs compared to healthy controls. Dogs with suspected neoplasia
had significantly higher CRP (P=0.011), haptoglobin (P=0.008) and SAA (P=0.05),
and lower albumin (P=0.012) concentrations compared to dogs with benign
esophageal nodules. APPs moderately discriminated between suspected malignant and
benign esophageal disease. None of the dogs with suspected neoplasia had
concurrent normal concentrations of all APPs. The present results indicate that
canine spirocercosis is characterized by an acute phase reaction, both at
presentation and during treatment. When concentrations of all four APPs are
within reference range, esophageal malignancy is highly unlikely. Although
concentrations of all positive APPs were significantly higher in suspected
neoplastic cases compared to benign ones, moderate discriminatory power limits
their clinical use. Neither APP was useful to monitor response to treatment.
12. Vet Rec. 2012 Jun 23;170(25):648. doi: 10.1136/vr.100401. Epub 2012 Jun 1.

Acute phase protein levels in dogs with mast cell tumours and sarcomas.

Chase D(1), McLauchlan G, Eckersall PD, Pratschke J, Parkin T, Pratschke K.

The acute phase proteins (APP) form part of a non-specific host response to
inflammation. They may be induced by a range of different causes, including
infection, inflammation, cancer and trauma. As they form part of the earliest
response to such insults, they have potential for early identification of
disease. In people, APP levels have been shown to correlate both with the extent
of disease and also the prognosis in several forms of neoplasia, including
prostate, oesophageal and colorectal cancer. As such, they can be used as
prognostic and monitoring tools. To date, similar studies in veterinary patients
have been limited, largely retrospective in nature and many are non-specific for
tumour type. The purpose of this study was to evaluate a panel of four APPs in
dogs with naturally occurring mast cell tumours (MCTs) and sarcomas to identify
in the first instance whether increased levels of individual APPs, or
identifiable combinations of APPs, was linked with the presence of disease. In
the patients with MCTs, C-reactive protein (CRP) and a-1 acid glycoprotein levels
increased, with a concurrent drop in serum amyloid A levels. In the sarcoma
patients, CRP, a-1 acid glycoprotein and haptoglobin were increased. These
findings suggest that specific solid tumour types in dogs may be associated with
specific changes in APP profiles.
13. Vet Clin Pathol. 2009 Sep;38(3):348-52. doi: 10.1111/j.1939-165X.2009.00139.x.
Epub 2009 Apr 16.

Evaluation of serum haptoglobin and C-reactive protein in dogs with mammary
tumors.

Planellas M(1), Bassols A, Siracusa C, Saco Y, Giménez M, Pato R, Pastor J.

Author information:
(1)Department of Animal Medicine and Surgery, Universitat Autonoma de Barcelona,
Barcelona, Spain. marta.planellas@uab.cat

BACKGROUND: In veterinary medicine, there is increasing interest in measuring
acute phase proteins as a tool in the diagnosis and monitoring of neoplastic
diseases. Although mammary neoplasms are the most common type of cancer in dogs,
acute phase proteins have not been extensively evaluated in dogs with mammary
tumors.
OBJECTIVES: The aim of this study was to evaluate serum haptoglobin (Hp) and
C-reactive protein (CRP) concentrations in the dogs with mammary tumors and
assess their potential association with malignancy.
METHODS: A retrospective study of dogs with mammary tumors was performed. Serum
concentrations of CRP and Hp were determined in healthy control dogs (n=20) and
dogs with mammary tumors before surgery (n=41). Mammary tumors were grouped as
carcinomas (n=24), fibrosarcoma (n=1), malignant mixed tumors (n=7), benign mixed
tumors (n=6), and adenomas (n=3). CRP and Hp concentrations were compared in dogs
with different tumor types and were also compared based on tumor size, lymph node
infiltration, skin ulceration, fixation to underlying tissue, and time between
tumor identification and removal.
RESULTS: Hp concentration was significantly (P<.043) higher in dogs with mammary
tumors (median 2.03 g/L, range 0.09-2.94 g/L) compared with controls (1.38 g/L,
range 0.08-3.00 g/L), but the range of values overlapped considerably. CRP
concentration was higher in dogs with carcinomas (4.70 mg/L, range 0.63-128.96
mg/L) vs controls (2.11 mg/L, range 0.25-6.57 mg/L) (P=.0008) and in dogs with
ulcerated skin (14.8 mg/L, range 5.7-128.9 mg/L, n=3) compared with those without
ulceration (2.4 mg/L, range 0.11-30.3 mg/L, n=38) (P=.048).
CONCLUSIONS: Serum Hp and CRP do not appear to have value in diagnosing or
predicting malignancy of mammary tumors in dogs. Higher CRP concentrations in
dogs with mammary carcinoma suggest a role for inflammation in this tumor type.

PMID: 19392756  [PubMed - indexed for MEDLINE]
14. J Vet Intern Med. 2007 Nov-Dec;21(6):1231-6.

Serum C-reactive protein concentration as an indicator of remission status in
dogs with multicentric lymphoma.

Nielsen L(1), Toft N, Eckersall PD, Mellor DJ, Morris JS.

BACKGROUND: The acute-phase protein C-reactive protein (CRP) is used as a
diagnostic and prognostic marker in humans with various neoplasias, including
non-Hodgkin’s lymphoma.
OBJECTIVE: To evaluate if CRP could be used to detect different remission states
in dogs with lymphoma.
ANIMALS: Twenty-two dogs with untreated multicentric lymphoma.
METHODS: Prospective observational study. Blood samples were collected at the
time of diagnosis, before each chemotherapy session, and at follow-up visits,
resulting in 287 serum samples.
RESULTS: Before therapy, a statistically significant majority of the dogs (P =
.0019) had CRP concentrations above the reference range (68%, 15/22). After
achieving complete remission 90% (18/20) of the dogs had CRP concentrations
within the reference range, and the difference in values before and after
treatment was statistically significant (P < .001). CRP concentrations of dogs in
complete remission (median, 1.91; range, 0.2-103) were significantly different (P
= .031) from those of dogs with partial remission (median, 2.48; range, 0-89),
stable disease (median, 1.77; range, 1.03-42.65), or progressive disease (median,
8.7; range, 0-82.5). There was profound variation of CRP measurements within each
dog.
CONCLUSIONS: CRP is useful in determining complete remission status after
treatment with cytotoxic drugs. However, the individual variation between dogs
means CRP concentration is not sufficiently different in other remission states
to permit its use in monitoring progression of the disease. Greater reliability
in determining remission status might be achieved by combining CRP concentration
with other serum markers.

15. Vet J. 2007 Jul;174(1):188-92. Epub 2006 Aug 9.

Changes in C-reactive protein and haptoglobin in dogs with lymphatic neoplasia.

Mischke R(1), Waterston M, Eckersall PD.

Acute phase proteins (APP) are regarded as a useful diagnostic tool in humans
with lymphomas, leukaemias and multiple myeloma. C-reactive protein (CRP) and
haptoglobin concentrations were measured in dogs with malignant multicentric
(high grade) lymphoma (n=16), acute lymphoblastic leukaemia (ALL) (n=11), chronic
lymphocytic leukaemia (CLL) (n=7) and multiple myeloma (n=8). Twenty-five healthy
dogs served as controls. Measurements of the CRP plasma concentration were
performed using a commercial ELISA and haptoglobin was measured with an assay
based on its haemoglobin binding capacity. Global group comparisons using
Kruskal-Wallis-test revealed significant group differences for both APPs
(P<0.0001). Median CRP concentrations were increased in all groups with
neoplastic lymphatic disorders (lymphoma: 37.2mg/L, ALL: 47.8mg/L, CLL: 35.5mg/L,
myeloma: 17.6mg/L) compared to controls (1.67mg/L; P<0.001). Compared to the
healthy controls (median=0.59g/L), haptoglobin was especially increased in dogs
with ALL (6.8g/L, P<0.0001) followed by dogs with malignant lymphoma (3.8g/L,
P<0.0001), CLL (3.2g/L, P=0.0008), and multiple myeloma (3.0g/L, P=0.0163). For
both APPs, a wide range of values was found in all patient groups. The results
indicate that particularly severe and acute lymphatic neoplasia, such as high
grade lymphoma and ALL, cause significant acute phase reactions in dogs and must
be included in the differential diagnoses of increased blood levels of these
APPs.

16. J Am Vet Med Assoc. 2007 Feb 15;230(4):522-6.

Serum C-reactive protein concentrations in dogs with multicentric lymphoma
undergoing chemotherapy.

Merlo A(1), Rezende BC, Franchini ML, Simões DM, Lucas SR.

OBJECTIVE: To determine whether serum C-reactive protein (CRP) concentration is
high in dogs with multicentric lymphoma, whether CRP concentration changes in
response to chemotherapy, and whether CRP concentration can be used as a marker
for relapse in dogs with multicentric lymphoma.
DESIGN: Cohort study.
ANIMALS: 20 dogs with multicentric lymphoma and 8 healthy control dogs undergoing
chemotherapy with cyclophosphamide, vincristine, and prednisone (CVP) or with
vincristine, cyclophosphamide, methotrexate, and L-asparaginase (VCMA) and 20
other healthy dogs.
PROCEDURES: Serum CRP concentration was measured weekly during the first month of
chemotherapy and then at 3-week intervals until relapse in dogs with multicentric
lymphoma, weekly for 16 weeks in healthy dogs undergoing chemotherapy, and once
in the healthy dogs not undergoing chemotherapy.
RESULTS: For both groups of dogs with lymphoma, mean serum CRP concentration
during week 1 (prior to treatment) was significantly higher than mean
concentrations following induction of chemotherapy and at the time of relapse.
Mean serum CRP concentration in the healthy dogs undergoing chemotherapy was not
significantly different at any time from mean concentration for the healthy dogs
not undergoing chemotherapy. No significant differences were observed between
dogs treated with CVP and dogs treated with VCMA.
CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that serum CRP concentration
is high in dogs with multicentric lymphoma but that serum CRP concentration is
not a useful marker for relapse and that chemotherapy itself does not affect
serum CRP concentration.

19. J Vet Intern Med. 2005 Nov-Dec;19(6):865-70.

Preliminary studies of serum acute-phase protein concentrations in hematologic
and neoplastic diseases of the dog.

Tecles F(1), Spiranelli E, Bonfanti U, Cerón JJ, Paltrinieri S.

Serum concentrations of acute-phase proteins (APPs): haptoglobin (Hp),
ceruloplasmin (Cp), serum amyloid A (SAA), and C-reactive protein (CRP) were
determined in healthy dogs (n = 15) and dogs with different diseases grouped as
acute inflammation (I, n = 12), hematologic neoplasias (HT, including leukemia
and lymphoma, n = 16), nonhematologic neoplasias (NHT, including epithelial,
mesenchymal, and mixed, n = 20), and autoimmune hemolytic anemia (AIHA, n = 8).
SAA and CRP were analyzed using commercially available enzyme-linked
immunosorbent assay (ELISA) kits, and Hp and Cp were measured using colorimetric
methods, all previously validated for use in dogs. Increased concentrations of
all APPs were observed in all groups of diseased dogs, but statistical
significance only was observed with Hp (I, P < .001; HT, P < .05), Cp (I, P <
.05; AIHA, P < .01), and CRP (I, P < .001; HT, P < .001; AIHA, CRP P < .05). High
variability in individual APPs within each group of diseases was found with no
significant differences between leukemia and lymphoma as well as among different
types of neoplasia. The AIHA group had smaller increases in Hp, SAA, and CRP but
higher concentrations of Cp. When follow-up of individual cases was possible, a
decrease in APPs generally was found in cases with favorable outcome. The results
of this study suggest that neoplasia and hematologic diseases such as AIHA should
be considered as possible causes of mild increases in APPs in dogs. Measurement
of APPs may be helpful to assess clinical evolution and monitor treatment of
these processes.

20. Biochem Biophys Res Commun. 2003 Jan 31;301(1):212-7.

The canine mast cell activation via CRP.

Fujimoto T(1), Sato Y, Sasaki N, Teshima R, Hanaoka K, Kitani S.

We report here canine mastocytoma-derived cell (CMMC) activation via two
pentraxin, limulus- and human-CRP. Mast cell chemotaxis was measured by Boyden’s
blindwell chamber. To confirm that the cell migration was chemotactic,
“checkerboard” analysis was performed. We used Fura-2 to investigate CRP-mediated
cytosolic calcium elevation. To examine whether CRP-induced stimulation is
mediated through G-proteins, CMMC were incubated with pertussis toxin (PTx)
before use in chemotaxis assay and Ca(2+) mobilization. CMMC migration in
response to CRP was both chemokinetic and chemotactic. Limulus-CRP induced a
transient Ca(2+)-mobilization dose-dependently. Preincubation of the cells with
PTx inhibited CRP chemotaxis and Ca(2+)-mobilization, suggesting that G-proteins
of the Gi-class are involved in the chemotaxis. We suggest that CRP may
participate in the migration of mast cells to inflamed tissues during an
acute-phase response. CRP-mediated recruitment of mast cells might play an
important role in hypersensitivity and inflammatory processes.

 

 

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