Two years ago, I wrote about an herbal product called Neoplasene, an excharotic derived from bloodroot that is marketed for treatment of cancer. I pointed out in that article that apart from a couple of in vitro studies suggesting the active chemical ingredient has some interesting effects on cancer cells, there is little evidence the product is an effective cancer treatment. And there is ample anecdotal and in vitro evidence of harm caused by the product, which kills healthy tissues as well as cancer cells and has been shown in humans to create horrible wounds while leaving hidden cancer that later spreads and kills the patient. No controlled research has been done in dogs and cats, and there is no reliable evidence to support the claims made by the marketers of this product.
Nevertheless, due to the power of anecdotes, and the weakness of government regulation of herbal products, this preparation is still marketed for use, and there are veterinarians who employ it. A recent case report in the Journal of the American Veterinary Medical Association (JAVMA) discusses the lack of evidence supporting the use of bloodroot and illustrates the significant harm these products can do.
Childress, MO. Burgess, RC. Holland, CH. Gelb, HR. Consequences of intratumoral injection of a herbal preparation containing bloodroot (Sanguinaria canadensis) extract in two dogs. Journal of the American Veterinary Medical Association 2011;239(3):374-379.
The report discusses two dogs, belonging to the same owner, who had Neoplasene injected into skin tumors. The first, a 2 year old golden retriever, had a benign tumor about 2cm in diameter. Such masses usually cause no problem for dogs, but if they are disturbing to owners or if they become injured or infected, they can be easily removed surgically, which is curative. Unfortunately, the treating veterinarian elected to inject the mass with Neoplasene. Six days later, the tumor had become bruised and much larger. The veterinarian instructed the client to give an oral homeopathic remedy to reduce the swelling of the tumor (which, given the mountain of evidence that homeopathy is nothing more than water and a bit of placebo effect, cannot reasonably viewed as an acceptable standard of care). After the swelling failed to resolve following drainage and bandaging, the pet was taken to the hospital of the veterinary medical school at Purdue University. By this time the benign 2cm diameter mass had become a 6cm area of severely inflammed and necrotic (dead) tissue.
The dog had surgery to remove the mass and a margin of healthy tissue around it, which involved a very extensive surgical procedure. After many weeks involving several additional surgical procedures and physical therapy to treat the loss of mobility caused by the large wound, the patient eventually made a full recovery.
The second patient discussed in the report, owned by the same client and treated by the same original veterinarian as the first dog, also had bloodroot injected into a benign tumor. A smaller amount of Neoplasene was used, and it appears that some of this leaked out after the injection. As a consequence of this, or perhaps of the variability in unregulated herbal products, the tissue reaction was not as severe as in the first patient. When the mass was surgically removed, an area of inflammation and tissue necrosis was observed near but not in the tumor. Luckily, this dog experienced minimal complications.
Clearly, complications can occur with any medication or treatment that has a measurable physiological effect. Anything that has no possibility of any side effects isn’t doing anything! And it is important to remember that anecdotes cannot be used to prove either the safety or the efficacy of a treatment. Anecdotes of benefit provide only enough evidence to justify more rigorous, systematic testing, not proof that a therapy works. In the majority of cases, such anecdotes turn out not to be accurate when more objective testing is done. Cases in which harm may have resulted from a treatment also cannot prove the treatment is unsafe. They do, however, provide reason to be cautious, and they raise the level of supportive evidence of benefit that should be expected prior to employing the treatment. Medicine is always about balancing the urgency of intervening in a patient’s condition with the available information about the risks and benefits of the intervention.
In the case of bloodroot, there is limited preclinical evidence to suggest it might be a useful treatment. It does kill cancer cells, but so does bleach, which is obviously not a good candidate for use as a medicine. The evidence that bloodroot kills cancer cells and spares healthy tissues is weak and contradicted by numerous cases of obvious tissue damage following application of the chemical. And there simply are no clinical studies to indicate a benefit in actual patients, much less a benefit greater than the potential risks. So we are left with anecdotes about bloodroot curing patients, which are of limited value as such anecdotes are often wrong for many reasons, and anecdotes of patients suffering severe, sometimes disfiguring or disabling injury after using it. Severe injury may not always happen, but it is an extreme risk to take when there is no real reason to expect the treatment has any benefit. Both of these patients would have been effectively cured, with much less suffering, injury, and expense for the owner, if they had been treated with conventional surgery rather than bloodroot.
Given the current state of the evidence, it is irresponsible of veterinarians to use bloodroot products on their patients. And in my opinion it is absolutely unethical for companies and individuals to profit from marketing these remedies without investing the resources in proper clinical studies to prove that they can be used safely and that they actually benefit patients. As I have discussed many times, herbal remedies are likely the most promising area of alternative medicine in which we will hopefully find effective medicines. But until they have been rigorously tested, and until they are regulated as stringently as pharmaceuticals, they are a dangerous gamble with our pets’ health and cannot reasonably be viewed as an alternative to established conventional treatments. Just as the pharmaceutical industry must be carefully watched to constrain the bad behavior that the profit motive can generate, so the herbal medicine industry cannot be trusted to provide trustworthy information and safe and effective remedies without much more oversight that it currently receives.