Complementary and Alternative Therapies in Veterinary Oncology
Many owners of a pet with cancer wish to try anything that may help their pet, and in doing so are interested in trying complementary and alternative therapies either instead of or in addition to “conventional” therapies.
We fully understand this; but there are some hazards that you should be alert to. We take a “holistic” approach to patient care, in that we take the whole pet into account in our recommendations (“treat the patient, not the cancer!”) and always prioritize quality of life. But confusingly, the word “holistic” is also used to describe a medical approach focused on complementary and alternative therapies in preference to conventional therapies. We don’t prescribe complementary and alternative treatments because, firstly, it is a body of knowledge in itself, and secondly, our philosophy of medicine is to prioritize evidence-based decisions where possible. We do strongly recommend that if you want to explore complementary and alternative therapies to see a veterinarian specially trained in that area. The internet is a boon for salespeople who capitalize on the fears and hopes of owners of pets with cancer.
Typically these claims lack data from controlled clinical trials showing safety and efficacy, and because the substances are not regulated as drugs, they are not required to be produced according to GLC so contamination and inconsistent potency are relatively common problems. Once data showing safety and efficacy is available for any particular substance, it becomes part of “mainstream” medicine. There are little published data on most of the “alternative” medicines. It is also very difficult to identify any potential toxicity, as most patients are receiving multiple different types of supplement, which confuses the issues. Other compounds may cause toxicity; for example, although rare, xiao-chai-hu-tang is documented to cause acute hepatic disease.
This is based on a single case report, but so is the “efficacy” on which it is being prescribed for many patients. It also has been associated with interstitial pneumonitis. Some direct experience we have is that some of our patients also receive Five Mushroom Extract; used in the assistance of treatment for cancer and chemotherapy for “immune support”; consisting of various Chinese Mushrooms, including Cordyceps, Shitake, Reishi, and Tremella. We had one patient that developed severe and acute liver toxicity and possible gastric ulceration that continued despite stopping chemotherapy but then resolved after ceasing the alternative medications (but there were approximately 20 of them so it’s not possible to identify the actual causative agent), and those signs did not recur when chemotherapy was restarted.
In dogs with lymphoma, the only study published so far has been for Maitake mushroom as a treatment. There was no decrease in lymph node size (objective response) seen in any of the dogs. Thirteen dogs developed progressive disease before the 4th week. Another study investigated Coriolus versicolor (Yun-Zhi) for dogs with haemangiosarcoma, and claimed improved survival in the abstract, but in the article, the improvement in survival was not significant statistically, and was based on 5 dogs; there was no discussion about tumour grade (which markedly affects survival). An interesting statistic to consider when thinking about where the new “cures” for cancer come from is that between 1990 and 2005, there were 920 anticancer compounds that underwent clinical trials (so these are ones that got beyond the initial testing of in vitro and mice testing and into human subjects) in the USA.
Of these only 32 were found to be effective. Many got as far as late-stage clinical testing before being found to be ineffective. It is important when evaluating whether to use untested “alternative” drugs in your pet, that the likelihood of finding true benefit is probably no greater than for traditional drugs; in other words, it would have only a 3.5% chance of actually benefiting him or her, but without the testing and analysis that we require “conventional” drugs to go through, we will never know which of the alternative medications might work. Separate to that is the question of “supplements” to reduce the toxicity of chemotherapy. In truth we do a good job of this with antiemetics and antibiotics, so unless there is a specific problem with an individual patient’s chemotherapy, we are not sure there is an advantage to adding more chemicals (even if “natural”). However, we totally understand that owners wish to try anything that may help their pet, and we try to support this.
Many of our patients do also receive complementary and alternative treatments in addition to their conventional treatments, and if it is done safely and sensibly there is usually no problem with this. We do advise avoiding antioxidant supplements at the same time as chemotherapy, as antioxidants can interfere with the mode of action of chemotherapeutics, and thus reduce the effectiveness of treatment.
So again, if you really want to pursue complementary and alternative treatments, see a veterinarian specially trained in that area. Be aware that there are many unscrupulous salespeople out there ready to prey on uninformed people – and a plethora of “offerings” – so you need to do a lot of reading to sort out what is what. This phenomenon isn’t new of course, the internet just makes it easier.
We have found one of the best explanations of these concerns in a veterinary website, voiced by SkeptVet; http://skeptvet.com/Blog/2014/03/tumexal-wonder-drug-of-snake-oil/.
The Cancer Council of Australia has a booklet called “Understanding Complementary Therapies” that you may want to have a look at (http://www.cancercouncil.com.au/1987/b1000/complementary-therapies-40/understanding-complementary-therapies-using-therapies/?pp=74162&cc=4233&&ct=35).