An interesting article appeared recently in a widely-read veterinary journal that discusses so-called “integrative medicine” in veterinary cancer care in terms of evidence-based medicine (EBM). This article raises a number of interesting questions and concerns.

Raditic, DM. Bartges, JW. Evidence-based integrative medicine in clinical veterinary oncology. Vet Clin Small Animal 2014;44:831-853.

I’ve written about the notion of “integrative veterinary medicine” (IVM) before, and it is a highly problematic concept. These authors define it as “the use of complementary and alternative medicine (CAM) with conventional Western medicine systems.” This already contains some fallacies in that it labels science-based or “conventional” medicine as “Western,” which ignores the fact that the scientific approach to health and disease that underlies modern medicine has been developed and very successfully employed in all cultures around the world. While much of the development of modern science initially took place in Europe and North America, critical contributions to scientific medicine have come from many other places. And there is nothing intrinsically “Western” about scientific medicine. It has come to dominate medical practice around the world because of its demonstrable success, crossing cultural barriers rapidly and continuously.

This label also implies that the alternatives to conventional scientific medicine are fundamentally culturally distinct in origin and character. This may be true for some, such as Traditional Chinese Medicine (itself somewhat misleadingly named), but it is certainly not true for chiropractic, homeopathy, and many herbal and nutritional therapies which are include under the CAM umbrella and yet which were invented and practiced predominantly in Europe and North America.

In any case, defining IVM and the use of CAM along with conventional medicine begs the question of what CAM itself really is. As I’ve discussed before, it is largely an ideological category with little scientific meaning. It exists in part because of fundamental philosophical differences between CAM practitioners and proponents of science-based medicine, and partly to protect specific therapies in which proponents have personal faith from criticism and rejection regardless of the state of the scientific evidence concerning them. To call something CAM is not to define it, since many of the therapies included under the label are mutually incompatible in fundamental ways and have very different evidentiary profiles. The label signifies a particular kind of attitude and belief, not a real difference from the perspective of how or if one can demonstrate these therapies to be safe and effective using scientific means.

The authors further expand on their definition of IVM by defining CAM in terms of specific therapies they would include in the category and, tellingly, as anything “that are rational and supported by evidence to alleviate physical and emotional symptoms, improve quality of life (QOL), and possibly improve adherence to oncology treatment regimens.” This definition contains within it the assumption that these therapies are rational and supported by evidence. However, this often turns out not to be true for many of the practices included in the CAM fold, so this cannot be justly blithely assumed.

The authors then go on to justify the importance of knowledge about CAM therapies by pointing out some CAM therapies are widely employed. I agree, and I think it is vital that clinicians understand what the category itself is about and what the evidence says about specific therapies, though I suspect my conclusions would be quite different from those of the authors. They also acknowledge that the major drive for use of these therapies is psychological rather than based on any objective reason to expect they are safe and effective:

…human oncology patients use natural products to empower themselves, attempt to take control of their health… logically pet owners would apply these same emotions.

Once again, I agree, and I think it is important that veterinarians understand the roots of CAM use among our clients. This doesn’t mean, as the authors appear to imply, that we must support or encourage these practices, only that we must be knowledgeable about them and effective in understanding and communicating with our clients about their use. Often, if we are practicing truly evidence-based medicine, this communication is likely to involve discouraging the use of therapies for which there is no good reason to expect they are safe and effective.

The authors go on to acknowledge that the research evidence, particularly the most useful types of research, clinical trials, is scarce for most CAM practices. However, they imply that the reason for this is not the lack of a belief on the part of CAM practitioners that their therapies need scientific evaluation but simply a lack of funding for therapies that are not likely to be profitable:

Evidence-based research on CAM in an IM plan in veterinary clinical oncology is scarce, which is expected because large-scale research funding is typically provided for projects with potential for profits, such as with new, patented drugs.

This would seem to be contradicted by their own admission that, “In 2010, US herbal supplement sales exceeded $5.2 billion.” The reality is that CAM therapies are often very profitable. The reason herb and supplement manufacturers invest far less in scientifically evaluating the safety and efficacy of their products than to pharmaceutical companies is not because there is no profit to be made in these products but simply because the government does not require them to. Pharmaceutical products must demonstrate safety and efficacy to a certain, albeit imperfect, standard set by the FDA. Politics and ideology have led, however, to a different and far more lax standard for herbs and supplements, which are often assumed to be safe despite the abundant evidence that they can cause as much harm as conventional medicines.

In the absence of much clinical trial evidence, the authors place greater emphasis on less reliable kinds of evidence, such as in vitro and animal model studies and extrapolation across species. They hold out particular hope that metabolomics, the study of how the compounds and chemicals involved in metabolism are affected by particular diseases and interventions, such as herbs and supplements. While a great deal of useful knowledge can be gained by this kind of research, the study of such proxy markers for clinically relevant outcomes cannot substitute for clinical trials. The response of cancer cells in a petri dish or in a mouse to a purported cancer therapy have never proven to be very reliable indicators of the actual clinical response of cancer patients to the same therapy.

The rest of the article is largely a review of selected clinical and pre-clinical research on a few herbs, dietary supplements, and acupuncture. This is fine as far as it goes, but like any narrative review the only studies mentioned are the ones the authors, who are avowed proponents of such therapies, choose to discuss, so one has to bear in mind they may not be representative of the real state of the scientific evidence. In any case, what strikes me about this part of the paper is that the authors are describing the process of scientific evaluation of potential medical therapies from in vitro and animal model studies up through clinical trials. How, exactly, is there anything complementary or alternative about this?

What they describe is essentially the process of scientific, “Western” medicine, which routinely investigates the therapeutic and preventative value of such interventions. The only reason to call any of this alternative or distinguish it from conventional scientific medicine is to suggest that the use of these therapies should be somehow viewed differently from other medicines such as pharmaceuticals. The usual next step, which the authors never make explicit here, is to claim that these therapies should be open to use regardless of the state of the scientific evidence. They do, however, suggest that rather than evaluating the science for themselves as they would ordinarily do, veterinary oncologists should rely on the expertise and personal experience of veterinarians already using such therapies and already convinced of their value despite the lack of scientific evidence.

Collaboration between conventional oncologists and practitioners of IM, who have knowledge, experience, and training to use HDS and acupuncture, is needed to explore the possibilities of integrative veterinary…Although individual herbs are discussed here, integrative practitioners more often use herbal formulas and have identified safe, reliable sources of HDS products with known content; they also know possible interactions and understand dosing to prevent adverse effects. Veterinarians with this special training, education, and experience can be found through the organizations in Box 1.

The suggestion here is that these remedies can be viewed as “safe and reliable” and that adverse effects can be predicted and avoided despite the lack of scientific research simply because these veterinarians have personal experience in their use. This illustrates the underlying theme that occurs again and again in apologia for CAM. Proponents use language like “evidence-based” and promote supportive scientific research because these things have marketing value; they generate acceptance and the appearance of scientific validity. Yet in their hearts, the lack of scientific evidence for safety and efficacy does not diminish a confident belief in the safety and efficacy of these therapies. Science is a nice extra, something to convince the skeptics, but it isn’t seen as fundamentally necessary to the evaluation and safe use of these therapies. This attitude is incompatible with evidence-based medicine despite the appropriation of EBM terminology.

I appreciate the authors’ acknowledgement of the lack of convincing evidence to support the use of most CAM therapies in veterinary cancer care. And I agree that despite this, there is interest in such therapies on the part of clients. Veterinarians absolutely should be knowledgeable about these practices so they can guide and advise their clients. However, the appropriate response to the lack of good evidence for these practices is not to suggest that it cannot be obtained or that we can comfortably rely on individual experience and expertise instead.

Ultimately, for potential therapies with reasonable plausibility, the usual practice of science should be followed. Pre-clinical testing followed, if the evidence warrants, by clinical trials. Any use prior to the development of strong scientific evidence should be viewed as experimental, as likely to harm and to help the patient, and this should be clearly disclosed to clients. There is no reason to treat these therapies differently from any others or to give them special exemption from the usual standards of evidence.

By far the most common response to those posts I write questioning the claims for medical therapies advertised on the internet is a flood of testimonials from people who believe the scientific evidence is wrong or irrelevant because the product seemed to work for them and because so many people report it works. There are many reasons why anecdotes aren’t trustworthy, and I’ve written about this at length before. As psychologically compelling as our own experience are, and as hard-wired as we are to appreciate and believe stories more than data, the truth is that our uncontrolled observations are deeply unreliable.

Cognitive biases are a particularly significant part of the problem. These are little mental quirks and shortcuts that lead us to the wrong conclusions and to bad decisions. I’ve written about the effect of these biases on veterinary clinical decision making, and many, many books have been written about the specific details of these biases, how they work, and what effects they have on our reasoning**

A recent study has produced some specific and compelling evidence for the degree to which internet reviews of medical products grossly overestimate the actual value of the treatments being reviewed. The bottom line is that people who have positive experiences are far more likely to write testimonials than people who don’t, which creates a false impression of how well a therapy works, if it does at all.

Mícheál de Barra; Kimmo Eriksson; Pontus Strimling. How Feedback Biases Give Ineffective Medical Treatments a Good Reputation. J Med Internet Res 2014;16(8):e193)

The study first compared reviews of a diet plan on Amazon with results of clinical research on the same diet.

After 6 months on the diet, 93% (64/69) of online reviewers reported a weight loss of 10 kg or more while just 27% (19/71) of clinical trial participants experienced this level of weight change.

This figure shows the results of three clinical studies compared with those reported on Amazon. Clearly, the studies found consist results far less dramatic than those indicated by the online testimonials.

The same phenomenon was found when evaluating a dietary supplement/herbal product supposed to improve fertility.

And when the investigators evaluated the influence of reviews on decision-making, they found that positive reviews did affect people’s choice of a weight loss plan.

The author’s conclusions were:

We found that the reputed benefit of weight loss diets and fertility treatments is larger than the real benefit, apparently because people with typical or poorer outcomes are less inclined to tell others about their experiences. Thus, the real-world reputation of medical treatments seems to be subject to a reporting bias akin to the publication bias toward positive results that is seen in scientific research. Moreover, we found the resultant reputation distortion to be large enough to influence people’s decisions about which diet to begin…

Researchers have pointed out that several processes make it very difficult to identify benefits and harms of medical treatments when data are not systematically collected. In particular, treatments with no direct effect will sometimes appear effective because of the statistical phenomenon known as regression to the mean and the physiological phenomenon known as the placebo effect. It has also been suggested that treatments that prolong illness may, perversely, spread better because they are “demonstrated” for a longer period than effective treatments. Here, we have explored an additional mechanism, reporting bias, and its logical consequence: when people with poor outcomes remain silent, the reputed benefit of a treatment will exceed its real effect.

Though there are already more than enough nails in the coffin of the idea that anecdotes and testimonials can be trusted when making decisions about medical therapies, this study provides yet another solid reason not to rely on this kind of evidence. That will not, of course, stop people from responding to substantive, evidence-based critiques of specific products with pointless testimonials, but it will help remind all of us why these shouldn’t be taken very seriously.

**Brief Bibliography

Burton, R. (2008). On Being Certain: Believing You’re Right Even When You’re Not. New York: St. Martin’s Press

Carroll, RT. (2000) Becoming a Critical Thinker – A Guide for the New Millennium. Boston: Pearson Custom Publishing.

Gilovich, T. (1993). How We Know What Isn’t’ So: The Fallibility of Human Reason in Everyday Life. New York: The Free Press.

Kahneman, D. (2011). Thinking, Fast and Slow. New York: Farrar, Straus and Giroux.

Kida, T. (2006). Don’t Believe Everything You Think: The 6 Basic Mistakes We Make in Thinking. New York: Prometheus Books.

McKenzie, BA. Veterinary clinical decision-making: cognitive biases, external constraints,and strategies for improvement. Journal Amer Vet Med Assoc. 2014;244(3):271-276.

Park, RL. (2001) Voodoo Science: The Road from Foolishness to Fraud. Boston: Oxford University Press.

Sagan, C. (1995). The Demon-Haunted World: Science as a Candle in the Dark. New York: Random House.

Shermer, M. (1997). Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time. New York: Holt, Holt & Company.

Tavris C. Aronson, E. (2008) Mistakes Were Made (But Not by Me):Why we Justify Foolish Beliefs, Bad Decisions, and Hurtful Acts. Boston: Mariner Books.

Burch, D. (2009). Taking the Medicine: A Short History of Medicine’s Beautiful Idea and our Difficulty Swallowing It. London: Chatto & Windus

The Skeptic’s Dictionary

Veterinary Medicine and the Philosophy of Science

A recent editorial from Trends in Molecular Medicine does an excellent job explaining why clinical trials testing the effects of highly implausible therapies, like homeopathy and energy medicine, are not an example of evidence-based medicine but of science tricked into serving as advertising.

Gorski DH. Novella SP. Clinical trials if integrative medicine: testing whether magic works?
Trends in Molecular Medicine 2014; In Press

Clinical trials are the last in a series of steps to evaluate potential therapies, and those that fail at earlier levels, or that have not been subjected to appropriate pre-clinical testing, should not be inflicted on patients. It is unethical and dangerously misleading to conduct such clinical trials.

When poorly designed and conducted, such trials generate spurious positive findings that mislead. When properly designed and conducted, they most often generate negative findings (read Snake Oil Science for numerous examples). However these negative studies do nothing to discourage the use of these therapies among proponents. Conducting such studies in hopes of finding a rare exception in which they prove effective and long-standing scientific principles are overturned is not an efficient use of limited resources for testing novel therapies. We should focus our energy on therapies that don’t conflict with well-established principles of basic science and which are promising on the basis of pre-clinical research. Most of these will fail at the clinical trial level as well, of course, but at least the odds are somewhat better than for trials on what amounts to magic.

This is relevant to veterinary medicine as well as human medicine, though as usual the scope of the problem is smaller. For example, conducting trials of homeopathic remedies for cancer (Banerji Protocol as Adjunct Nanotherapy for Treating Canine Appendicular Osteosarcoma: A Double Blind, Randomized Study Design), despite the overwhelming evidence that homeopathy is inconsistent with fundamental and well-established laws of physics and chemistry and has consistently failed pre-clinical and clinical testing (1, 2), is simply unjustifiable ethically and scientifically. It is an irrational use of limited resources for investigation of novel treatments.

Here is part of Dr. Gorski and Dr. Novella’s conclusion from the editorial:

In RCTs [randomized controlled clinical trials] testing modalities with low pre-test probability (i.e., low plausibility), confounding effects are vastly magnified, easily producing false-positives. In these days of extreme scarcity of research funding, it is difficult to justify spending precious research dollars carrying out RCTs of treatments where the likelihood of producing a true positive trial is so low and that have real risks that can lead to outcomes like the TACT or pancreatic cancer trials. All clinical trials, not just RCTs, should be based on scientifically well-supported preclinical observations that justify them, preferably with biomarkers to guide patient selection and follow-up. Until specific CAM and IM modalities achieve that level of preclinical evidence, RCTs testing them cannot be scientifically or ethically justified. That is science-based, rather than evidence-based, medicine.

Sadly, many of the vets I talk to, even those who are sincerely committed to science and evidence-based medicine, appear to still believe that conducting clinical trials on even the most egregiously pseudoscientific therapies is appropriate and will make a difference in whether these therapies are chosen by clinicians. There was a time when I believed this. Unfortunately, this view doesn’t reflect the reality of alternative medicine research.

The problem is that the clinical trial literature, which is often questionable in mainstream human medicine and frequently poor quality in veterinary medicine overall, is consistently abysmal when it comes to alternative medicine research. I have previously reviewed the positive literature presented by the Academy of Veterinary Homeopathy last year in defense of homeopathy, for example. It took many hours of locating and reading dozens of papers in detail to determine that this evidence was thoroughly unconvincing. And yet these poor quality studies are constantly put forward as supportive of continued clinical use for these modalities, and the majority of clinicians simply don’t have the time or interest to go beyond the abstracts and appraise them critically.

Such studies create the appearance of legitimacy, which is used to make such modalities more widely acceptable even when the literature doesn’t actually support efficacy. In some cases, for example in China, negative trials of alternative therapies are virtually never published, which illustrates the uniquely unreliable nature of this literature. It is effectively marketing rather than science.

So in light of this, clinical trials of highly implausible treatments don’t accomplish their ostensible purpose. They don’t accurately evaluate safety and efficacy, and they don’t discourage the use of modalities that are pretty clearly ineffective. The work of the National Center for Complementary and Alternative Medicine (NCCAM) is another great example. This agency has spent billions of dollars testing therapies that have not met basic preclinical plausibility criteria. The vast majority of these trials have found no evidence of efficacy. And these results have had little effect on the popularity or use of the modalities studied. (3, 4, 5).

Now of course by saying “alternative medicine,” I am lumping together many very different approaches, most of which are mutually incompatible theoretically as well as sometimes inconsistent with the mainstream scientific understandings of health and disease. But I am not suggesting none of these deserve to be evaluated in clinical trials. Many herbal remedies, manual therapies, dietary manipulations, nutraceuticals, etc. are quite plausible and can and should be evaluated scientifically like any other novel therapy.

But when talking about methods which could only work if fundamental scientific principles upon which much of our technology and medicine is based is wrong (e.g. energy medicine, homeopathy, the theoretical structures of TCM, etc.), or which have effectively been disproven already (e.g. homeopathy, magnet therapy) I can see nothing to gain from clinical trials. They will almost certainly be of low quality and evidentiary value, and even if negative they will not discourage the use of such therapies.

And yes, there are plenty of different evidentiary problems with conventional medicine. Pharmaceutical companies often shamelessly manipulate data, treatments like hyperbaric oxygen and stem cell therapy are rushed into use well before sufficient evidence is available to justify this, and so on. But clinical trials examining therapies which either can’t work, unless much of established science is wrong, or which have already been extensively tested and failed to show evidence of efficacy, are simply wasteful and misleading.

And from an ethical perspective, it is truly disturbing to see veterinary cancer patients treated with homeopathy, especially when otherwise respected individuals and institutions are involved.. I think this is unfair to the patients even in the context of a clinical trial when there is so much evidence in human medicine that there have been systematic reviews of the systematic reviews of research on homeopathy (which, as I have discussed previously, have shown that the positive results come only from inadequately controlled studies).

It seems fundamentally unethical to do work such as this in the name of science when it is clear that nothing short of a miraculous overturning of established science could allow for a positive result, and it is equally clear that no one who believes in homeopathy is going to give it regardless of a negative outcome in such a trial. Such research wastes resources, creates no clarity, does not allow for real falsification, and exposes patients to therapies for which there is really no reasonable expectation of a benefit.

A number of interesting and important research studies have been published in the last 5 years on the subject of the risks and benefits of neutering in dogs, and these have provided important information to help guide veterinarians and owners in making decisions about neutering. I published a narrative review of the literature on neutering in 2010, before most of these papers appeared, and I have been following this area of study with interest and evaluating individual papers as they are published. Though each study has its limitations, as is always true in science, and we must be careful not to overgeneralize the results of particular studies or lurch wildly from one set of recommendations to another on the basis of limited evidence, these studies are influencing traditional dogma about neutering. I have made several significant changes in both the information I give to owners and the recommendations I make about neutering based on the emerging evidence.

Another important study has recently been published which adds to the evidence in this area.

Hart BL, Hart LA, Thigpen AP, Willits NH. Long-Term Health Effects of Neutering Dogs: Comparison of Labrador Retrievers with Golden Retrievers. PLoS ONE 2014;9(7): e102241. doi:10.1371/journal.pone.0102241

This study was produced by the same group which published an earlier retrospective study of Golden retrievers, and it is quite similar in its methods and some of its limitations. The authors reviewed medical records from the veterinary hospital at the University of California Davis veterinary college. The study looked for Golden retrievers and Labrador retrievers from 1 to 8 years of age and evaluated the occurrence of 6 diseases relative to neutering status and age at neutering.

The findings are summarized in Table 1 for Labradors and Table 2 for Golden retrievers. For comparison, I have also extracted similar data from the earlier paper by on Golden retrievers by the same group in Table 3. This paper classified age at neutering differently (early being <12 months of age and late being >12 months of age), so the studies are not directly comparable, but it is useful to scan for any possible patterns that might help us make sense of these complex data.

First off, what does the study appear to show? Well, perhaps the most important finding is that there are significant differences in the pattern of possible effects of neutering between males and females, and also between the breeds. This latter point is extremely important. People tend to jump on the findings from a study in a single breed and want to generalize those findings to all dogs and make broad recommendations based on that single study. However, if the possible effects of neutering differ significantly between two breeds as closely related and similar as Golden retrievers and Labrador retrievers, likely these effects will be even more dissimilar in breeds less closely related. A study of Rottweilers or Viszlas, for example, may tell us little or nothing about what to expect in Beagles or Poodles. This is worth keeping in mind before we rush into making sweeping recommendations for all dogs.

The findings in this study suggest some increase in the risk of some diseases with neutering, but the patterns were not very consistent. Neutering before 6 months of age appeared to be associated with higher risk of cruciate ligament disease and elbow dysplasia in male Labradors but not with the risk of hip dysplasia. In females, however, the pattern was the opposite, with neutering at less than 6 months being associated with greater risk of hip dysplasia but not the other two orthopedic diseases. But in Golden retrievers, neutering before 6 months of age was associated with greater risk of cruciate ligament disease in both sexes, but with greater risk of hip dysplasia only in males, not females.

Comparing the current study with the previous study of Golden retrievers also adds to the confusion. In the current study, risk of lymphoma seems to be higher in dogs neutered between 6-11 months than in intact dogs, but not in dogs neutered before 6 months or after 11 months. In the previous study, however, lymphoma risk appeared higher in males neutered before 12 months but not in females neutered at this age. In another example, late neutering in the first paper seemed to increase the risk of hemangiosarcoma in female Goldens but not in males. This was contrary to the hypothesis that earlier neutering might increase the risk of this cancer. However, in the current study, no differences in hemangiosarcoma risk were found for any neutered group of males or females compared to intact dogs.

There are, as always, a number of limitations that we must bear in mind when evaluating this study. As with the previous study, dogs were those seen at a university veterinary hospital. This is a very different population than usually seen at regular general veterinary practices. The veterinary hospital at UC Davis typically sees seen sicker dogs, dogs with more affluent owners, and dogs that live in different areas than those seen by regular practices in the rest of California. So we have to be careful about assuming than any relationships seen between health and neutering in this population will hold for the very different population of primary care practice patients.

Dogs younger than 12 months were excluded from this study. While the disease looked at are less common in dogs less than 1 year of age than in older dogs, they do occur. If dogs who get these diseases under 12 months are different, in terms of neuter status, from the dogs looked at in this study, that might change the apparent relationship. For example, if dogs who are intact are more likely to get one of these diseases earlier than neutered dogs, then excluding younger dogs would make neutering seem like a risk when it might actually be protective.

Similarly, dogs over 9 years of age were excluded as well. These dogs are particularly likely to get some of the cancers looked at in the study, and again if the ones who do differ in neuter status from the ones in this study, the apparent relationships identified in the study might be very different from the real relationships between these diseases and neutering.

A number of potential benefits of neutering, such as preventing mammary tumors and uterine infections in females and possibly being associated with longer overall lifespans, were not included in this study. While these are not directly related to the questions the authors sought to investigate, it is important that we consider overall risks and benefits when deciding when or if to neuter our dogs. If neutering prevents some cancers and increases the risk of others, for example, we need to make a decision about which effect is greater or more important in a particular dog. This study only looks at a small piece of that equation, namely the risks but not the benefits.

Finally, there are many comparisons made in this study, and each one is evaluated statistically. This can create a problem known as the multiple comparisons problems, in which the usual threshold for statistical significance is not appropriate. It is common, in studies which make multiple comparisons between subgroups and don’t correct for this problem to find a smattering of statistically significant results which are really the result of chance. In this study, I am not certain if a correction for multiple comparisons was made. If not, this could explain some of the significant differences found, particularly when the overall pattern is not consistent between studies or does not fit expectations based on biology.

Bottom Line
Overall, this study does suggest that neutering under 6-12 months of age might be associated with an increased risk of some orthopedic diseases in Golden retrivers and Labrador retrievers. In Labs, neutering does not appear to increase cancer risk. In Goldens, there may be some effect on cancer risk, but it differs between males and females. And in females, it may even be the case that earlier neutering is associated with a lower cancer risk than neutering later in life. But there are a number of inconsistencies and limitations which make these findings tentative at best.

The study also appears to show a strong difference in the effects of neutering on disease risk between even very closely related breeds. So it is important to recognize that the effects seen in one breed cannot reliably predict those that might be seen in another.

No single, universal recommendation for neutering or not neutering dogs of any sex, breed, or age is justified by the scientific evidence. There is some suggestion that females may experience significant health benefits, particularly in prevention of pyometra and mammary tumors, though the evidence concerning mammary tumors is weaker than generally believed. For males, there does not seem to be a compelling, consistent health benefit to neutering, and in large breeds there may be some benefit to waiting until after 1 year of age. In any case, as I always stress, it is important to balance potential risks and benefits carefully.

And not all benefits of neutering are related to the health of the individual dog. Millions of unwanted dogs are born and euthanized in the U.S. every year, and while every client I talk to dismisses the possibility that their dog could contribute to that problem if left intact, most of these dogs are the product of breeding by owned pets. So if you choose to keep your dog intact for health reasons, it is important to accept that this creates an additional responsibility to make sure he or she does not contribute to the serious problem of overpopulation and the suffering and euthanasia of unwanted dogs.

With my own clients, I discuss the complexity and inconsistency of the evidence, the general trends that seem to be apparent, and the important of making individualized decisions based on all the relevant factors, including age, breed, sex, intended purpose, and the circumstances of the owner. For the most part, I recommend neutering of females before their first heat, though the evidence is still not ironclad and more work needs to be done to elucidate the details of potential risks and benefits in different breeds and with different neutering ages. For males, I no longer see a compelling reason to neuter unless there is clear evidence of aggression towards other dogs, however I emphasize to owners that they must be aware of the added responsibility to prevent roaming and unwanted breeding.

These recommendations are different from those I gave when I first graduated from veterinary school, and they have changed as a result of changing and improving evidence. Likely they will continue to evolve as more research is done and we have a better understanding of the issue.

Table 1

Table 2

Table 3

I write regularly about the American Holistic Veterinary Medical Association (AHVMA) and its fundraising arm the American Holistic Veterinary Medicine Foundation (AHVMF). These organizations are very much the tip of the spear for pseudoscience in veterinary medicine. Unfortunately, despite peddling ideas which are often fundamentally incompatible with well-established science and with the evidence of history that science is the best way to understand the world and improve health, these organizations are remarkably effective at pretending to have a genuine interest in scientific research of alternative therapies, raising large sums of money (AHVMA and AHVMF financial statements), and then using that money and that superficial appearance of accepting the importance of science to infiltrate academic institutions and veterinary organizations.

From time to time, the leaders of these organizations share their true feelings about science and science-based medicine, and I feel it is useful to draw attention to those so that, hopefully, the truth beneath the façade will be visible and both veterinarians and pet owners can make fully informed judgments about the intentions and agendas of these groups.

In a recent interview in Natural News, a well-known platform for promoting the most egregious anti-science quackery, the president of the AHVMF, Dr. Barbara Royal, presented an honest and quite bizarre characterization of science-based veterinary medicine.

Dr. Barbara Royal, president elect of the American Holistic Veterinary Medical Foundation, believes that mainstream American physicians and veterinarians are only educated in one way.

“MDs and DVMs learn a lot about surgery, a lot about medications, a lot about disease…but they don’t learn about the causes of health.”

Royal believes in an integrative approach to health, NOT interventionist medicine. She strives to focus on supporting pet health as a first priority instead of treating disease after it has developed. This philosophy is challenging the status quo. Today’s mainstream veterinary students are taught to treat pets with an approach emphasizing drugs and surgery.

Throwing a drug at the problem often leaves pets with side effects and an impending death. The philosophy of, “take this drug, we don’t really know how it works, good luck,” is a symptom cover-up approach that reaps more consequences in the end. Although mainstream veterinarians mean well and want to help, their philosophy – the way they were taught – is a patch work that ultimately leads to unintended consequences.

The clichés that conventional medicine treats only symptoms without any interest in the underlying causes of disease, that preventative healthcare is ignored by conventional veterinarians, and that science-based medicine ignores all interventions except surgery and pharmaceuticals are often repeated by proponents of alternative approaches despite being obviously and manifestly untrue.

Dr. Royal offers a few tidbits from the alternative perspective the AHVMF advocates, which include further clichés, such as blaming mysterious toxins, conventional diets, vaccines, and of course medicines (ah, I mean “drugs”) for illness and suggesting that without the products of science-based medicine our pets would be living natural, healthier lives. It is hard to imagine anyone making such an implication with a straight face given the overwhelming evidence that human health and longevity has improved dramatically since the advent of the scientific approach to a degree unimaginable during the thousands of years of pre-scientific approaches to health that sound very much like the “natural” approach the AHVMF advocates, complete with ancient healthcare strategies based on pseudoscience and mysticism like Traditional Chinese Medicine, Herbal Medicine, Acupuncture, and so on. (See the graphs below for a couple of illustrations of this well-documented history)**

She encourages pet owners to eliminate corn and wheat from their pet’s diets, because these are pro-inflammatory, unfamiliar ingredients to an animal’s body. She teaches about pet food processing methods that create heterocyclic amines and acrylamides, which are potent carcinogens.

She talks about concepts like the lack of moisture content in kibbles which lead to dehydration in the animal. She talks about the amount of glycotoxins in dog food that cause inflammation in pets.

Royal also warns against overdoing those things that could cause harm. She teaches not to over medicate or over-vaccinate a pet, teaching how this interferes with an animal’s natural ability to heal.

Like other leaders of these organizations, Dr. Royal pays lip service to the value of science when speaking to those who truly do recognize the importance of the scientific approach, but when speaking with fellow believers in alternative therapies, she makes no reference to scientific evidence at all but is quick to  offer the well-respected testimonial/anecdote as validation for the preceding rejection of science-based medicine and its philosophy and methods:

On the inspiring stories page of the AHVMF page, one can find many testimonials of pets cured through holistic means.

Despite being psychologically compelling, such miracle stories are not a reliable way to evaluate whether a healthcare intervention is safe and effective. But they are very effective as a marketing tool, which ultimately matters more to the AHVMA and AHVMF that inconveniences such as what is true.

The fact that Dr. Royal and others in these organizations have a deep, genuine faith in their methods is not in itself objectionable. What is disturbing, and dangerous for our patients, is that they seem able to obscure the fundamental rejection of science and science-based medicine at the core of their ideology.  The fact that an organization run by individuals who blithely mischaracterize conventional medicine, as Dr. Royal does in this article, and who reject the basic philosophy or the need for science can be welcomed as an affiliate within the American Veterinary Medical Association and as a source of funding for research and educational activities at schools of veterinary medicine is bizarre and disturbing. The growing influence of these organizations does not bode well for the future of veterinary medicine as a profession or, more importantly, for the continued progress in healthcare that benefits our patients.
**Here is a chart which reminds us that before the 20th century, and the advances in agriculture, sanitation, and medicine brought about by the accumulating scientific knowledge of the preceding two centuries, human life was short and few children could count on living to adulthood, much less a ripe old age. This pattern had remained unchanged for thousands of years despite the “ancient wisdom” of trial-and-error folk medicine now advocated by the AHVMA and AHVMF. The chart below, while more speculative that the one above, illustrates this based on all the evidence currently available.

This is the reality the AHVMA is so eager to ignore in favor of a naïve image of a Golden Age of health and well-being prior to the development of science and technology. No one can deny that the fruits of science have not always been benign or wisely used. But denying that overall human life is longer and healthier thanks to science than it ever was during the millennia we relied on more “natural” methods is irrational and dangerous.