"New" Cancers in Pets
"New" Cancers in Pets
May is Pet Cancer Awareness Month, with a focus on awareness and fundraising to help in the fight to end pet cancer. At The AMC, we believe that awareness and prevention are key to helping pets live longer, happier, and healthier lives. The AMC is thrilled to have recently received a generous grant from the Puccini Foundation in partnership with Blue Buffalo and Petco Foundation to support our current oncological research and to subsidize cancer treatment costs for the pets of our clients with limited financial means through the Buddy Fund.
May 2015 marks my 30th year as a veterinarian. That milestone has caused me to think about some of the changes that have occurred in oncology over the past three decades. One of these changes is the identification of “new” tumors which were unheard of 30 years ago.
Indolent Lymphoma of Dogs & Small Cell Lymphoma in Cats
When I graduated, lymphoma was one disease and we treated it with chemotherapy. Now with the knowledge gained from research and the availability of advanced testing, I can actually identify a population of my patients with lymphoma that need less treatment. Despite treatment with fewer drugs, these dogs and cats can have a long survival time. Most cases of feline lymphoma arise in the intestinal track. If a cat is lucky, the lymphoma will be comprised of tumor cells which are small in size, cleverly called small cell lymphoma. Cats with intestinal small cell lymphoma have an anticipated survival greater than two years with only oral chemotherapy agents. Dogs, especially Golden retrievers can develop a form of small cell lymphoma in their lymph nodes – we call this one indolent lymphoma. Like cats, these dogs may have prolonged responses to oral chemotherapy agents or possibly not require any treatment at all.
Injection Site Sarcomas
In the 1980s, laws regarding rabies vaccines in cats were enacted. Shortly thereafter, pathologists – the specialists who read biopsies – noticed a type of tumor, called sarcoma, were popping up in unusual locations on cats, locations that corresponded to vaccination sites. On the right, you see a biopsy from one of these tumors. After studying these sarcomas, veterinary pathologists and oncologists determined these tumors were related to injections under the skin, the most common injection being a vaccination. The identification of this new tumor type led to improved vaccines as well as changes in vaccination protocols. Guidelines for management of post vaccinal swellings help guide cat owners and veterinarians to achieve good outcomes if these tumors develop.
Histiocytes are cells of the immune system responsible for destruction of invading pathogens like bacteria and viruses. When histiocytic tumors were first reported in the dog in the early 1990s, these tumors commonly occurred in Bernese Mountain Dogs and contributed significantly to the short lifespan of this breed. We now diagnose these tumors in Flat-coated retrievers, Rottweilers and Golden retrievers. Julie Jackson of the Bernese Mountain Dog Club Health Committee reports, “The Bernese Mountain Dog Club is making headway on early diagnosis of this devastating disease. The Berner Community is a devoted, generous group, and we will soon have a genetic risk test for histiocytic tumors from University of Rennes in France. The test is currently available in Europe, and approval is pending in the United States.”
Gastrointestinal Stromal Tumors
Until about ten years ago, all sarcomas of the intestine were classified as tumors of the intestinal muscle: the benign leiomyoma or the malignant leiomyosarcoma. Recent research using advanced techniques in the biopsy laboratory have reclassified some of intestinal muscle sarcomas. The new tumors, gastrointestinal stromal tumors, or GIST, arise from very specialized cells in the intestinal muscles – cells that control the rhythmic contractions of the intestine and propel the food though the intestinal tract. Early research suggests GISTs have a mutation which may make them sensitive to a targeted chemotherapy drug currently used to treat mast cell tumors in dogs.
If all this talk about “new” cancers makes you nervous about your pet’s health, celebrate Pet Cancer Awareness Month by reviewing our slide blog, “10 Warning Signs of Cancer in Pets” and see your veterinarian if your pet has any of the warning signs.
The AMC is grateful for the generosity of the Puccini Foundation in partnership with Blue Buffalo and Petco Foundation, and their support of oncological care and research at The AMC.