Starting in January 2014, I write a monthly column in Dog Fancy magazine about cancer. Each month I answer client’s questions or discuss a topic relating to the diagnosis, treatment or prevention of cancer in dogs. Here are some questions from Dog Fancy readers that I was unable to answer in my column.
Q: After reading your article in March 2014 regarding cancer types and breeds, I have this question. One of my four legged buddies is a Bernese Mountain Dog Mix (Bernese Mountain Dog/Collie-English Cocker cross[very handsome boy] ) and I have read that the Bernese breed is at high risk for lymphoma, if you have a mix breed dog, does this decrease the chances of the dog getting cancer?
A: Bernese Mountain Dogs, Collies and English Cocker- your pet must be beautiful. The answer to your question as to whether mix breed dogs have a lower risk of certain cancers is yes, they do--sometimes. If you have two breeds that have a high predilection for developing any cancer, crossing these two breeds may or may not decrease the risk of cancer in the offspring. The reason for this is that veterinarians and geneticists are still unsure as to which specific genes predispose the breeds to the various types of cancer. In a very large study (see http://avmajournals.avma.org/doi/abs/10.2460/javma.242.11.1549) evaluating over 27,000 dogs, researchers at University of California-Davis School of Veterinary Medicine found no difference in the predisposition of cancer in purebred dogs when compared to mixed-breed dogs. However, there are specific cancers where mixed-bred dogs do have a lower predisposition than do certain pure breeds.
The most important consideration when deciding which breed of dog to get or whether to get a purebred or mixed breed is personal preference. Having a dog you love is THE most important factor.
Q: I read your article in Dog Fancy concerning common cancers in dogs. I was interested in the story concerning Maddy, the Border Collie diagnosed with lymphoma and that she is still in remission after 4 years. I was wondering what type of chemotherapy she received. My poodle was diagnosed last year but came out of remission after only 9 months. He underwent the CHOP protocol the first time and is currently undergoing the same treatment. I have been told he may have survive another 4 -5 months on this current treatment. What type of treatment do you recommend? Thank you.
A: Maddy was a spectacular dog and one of my favorites patients. She was treated with both chemotherapy and a bone marrow transplant. While not widely available, bone marrow transplants can improve the prognosis for dogs with lymphoma. The other therapies that we are currently using at The Veterinary Cancer Center in Norwalk, CT are chemotherapy alone and chemotherapy in conjunction with radiation therapy. The three major protocols we use are CHOP (cycylophosphamide, Hydroxydaunorubicin (doxorubicin), Oncovin (vincristine), Prednisone), MOPP (mustargen, Oncovin (vincristine), Procarbazine and Prednisone) and Lomustine (CeeNU, CCNU). These three protocols form the basis for many of our lymphoma treatments. There are certainly variations of these with the CHOP-MA protocol, one that I helped develop (see http://www.ncbi.nlm.nih.gov/pubmed/20230577), giving dogs with B cell lymphoma a prolonged survival time, 622 days, compared with most other variants.
The protocol that is best for your particular dog depends upon a variety of factors and your local veterinarian or veterinary oncologist would be the best person to advise you.