One of the biggest ironies I have encountered are carcinogenic chemotherapy drugs.
Sound odd to you? Well, I don’t blame you! When I first found out about it I was shocked. Medication used for fighting cancer actually increasing the odds for cancer later?
Now, before everyone gets reactionary, we have to temper this topic with the big picture. Chemotherapy has helped a lot of dogs live longer lives with good life quality. Let’s not forget that reality.
The problem is that this is an area of medicine where the treatments used can, at times, have real-life and quite severe side effects. This is simply a reality of conventional cancer care and needs to be accepted as the current state of affairs.
I discuss how to lessen chemotherapy side effects in detail in The Dog Cancer Survival Guide if you are interested in this topic.
Take cyclophosphamide (Cytoxan), a common chemo drug used in dogs. The truth is that this medication is a known human carcinogen, and the same was found in rodents. Here is some information on the topic.
Cisplatin is “reasonably anticipated to be a human carcinogen,” and is carcinogenic in lab rodents.
So what does one do with this information? How are we supposed to feel okay about the use of these drugs?
Well, the age of the dog has to be kept in mind. While nobody knows the exact timing of a possible cancer developing after exposure to these drugs, it likely takes a while. Although I cannot give real data, a guess could be 3-5 years or more.
So it would make sense that in a young or middle aged dog, one might reach for different chemo drugs, especially if a normal life expectancy (without the cancer) would be more than 3-5 years after the cancer. This is an uncommon situation.
These are very tough decisions as nobody has a crystal ball. However, as your dog’s primary health care advocate, you should be advised of all the facts. We don’t know whether a second cancer will develop, but we need to at least evaluate carefully.
All my best,
Dr. Demian Dressler is internationally recognized as “the dog cancer vet” because of his innovations in the field of dog cancer management, and the popularity of his blog here at Dog Cancer Blog. The owner of South Shore Veterinary Care, a full-service veterinary hospital in Maui, Hawaii, Dr. Dressler studied Animal Physiology and received a Bachelor of Science degree from the University of California at Davis before earning his Doctorate in Veterinary Medicine from Cornell University. After practicing at Killewald Animal Hospital in Amherst, New York, he returned to his home state, Hawaii, to practice at the East Honolulu Pet Hospital before heading home to Maui to open his own hospital. Dr. Dressler consults both dog lovers and veterinary professionals, and is sought after as a speaker on topics ranging from the links between lifestyle choices and disease, nutrition and cancer, and animal ethics. His television appearances include “Ask the Vet” segments on local news programs. He is the author of The Dog Cancer Survival Guide: Full Spectrum Treatments to Optimize Your Dog’s Life Quality and Longevity. He is a member of the American Veterinary Medical Association, the Hawaii Veterinary Medical Association, the American Association of Avian Veterinarians, the National Animal Supplement Council and CORE (Comparative Orthopedic Research Evaluation). He is also an advisory board member for Pacific Primate Sanctuary.