Cancer and Your Pets: What You Need to Know

Almost everyone has known a friend or loved one who has been affected by cancer. While cancer in humans is definitely prevalent, our pets are also afflicted with this disease.

According to Dr. Heather Wilson, assistant professor of oncology at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences, 50 percent of all dogs and 30 percent of all cats over the age of 10 will be diagnosed with some form of cancer.

Types of cancers most common in dogs include: lymphoma (tumor of the lymph nodes), mast cell tumors (skin tumors), and osteosarcoma (tumor of the bones). Some common types of cancer in cats are: lymphoma, squamous cell carcinoma (which affects the head, neck and mouth), and vaccine associated sarcomas.

"Cats are not nearly as prone to cancer as dogs, but one of the most common cancers in cats comes from vaccine injection sites," notes Wilson. "While you can pick and choose some vaccinations, rabies vaccinations are required by law. However, there is a non-adjuvanted rabies vaccine for cats that is less irritating, thus less likely to cause cancer and is available at most veterinary clinics."

The type of cancer your pet has can also be closely associated with its breed. In dogs, lymphoma is most common in Golden Retrievers, Boxers, and Labs. Mast cell tumors are common in dogs with short noses such as boxers, pugs, and bulldogs. Large breed dogs such as Rottweilers and Great Danes are more prone to osteosarcoma.

"There is very little distinction across breeds when it comes to cancer in cats," states Wilson. "However, cancer most commonly affects the Siamese breed of cats."

Once your veterinarian has diagnosed your pet with cancer you will then want to find a veterinary oncologist in your area that specializes in your pet's specific cancer.

"There are veterinary oncologists that specialize in medical oncology and radiation oncology. There are also surgeons that specialize in surgical oncology," explains Wilson. "The best way to find a medical oncologist in your area is to go to the American College of Veterinary Internal Medicine (ACVIM) website at www.acvim.org."

Treatment options range from chemotherapy, surgery, radiation therapy, and immunotherapy and are administered depending on the type and severity of the cancer.

"Chemotherapy is the number one treatment option for animals with lymphoma," says Wilson."While cure rates in dogs vary greatly with the type of cancer, overall response rates for dogs with lymphoma treated with the CHOP chemotherapy protocol (a multidrug protocol given weekly over 19 weeks) is greater than 80 percent."

Response rates for dogs with mast cell tumors varies depending on the grade, but with complete surgical excision plus radiation for low grade tumors the control rates is often greater than 80 percent at three years.

"Unfortunately, the majority of dogs with osteosarcoma and metastatic disease do not achieve a cure," states Wilson. "Also, most cancers in cats are also very hard to cure. When we do achieve remission in cats with vaccine associated sarcomas, they often live 18-24 months before they have a recurrence."

Cost is another important thing to consider when deciding on the treatment of an animal for cancer. While costs range widely, the average cost for a surgery is $2,000-$3000; Chemotherapy regimen is $1,200-$3,000, and radiation averages $3,000.

"As cost is prohibitive to some families, a good option may be to enter your pet into a clinical trial if possible," notes Wilson. "Many of these trials have a financial incentive such as a free treatment regimen, and they also help with future research for both veterinary and human oncology."

For more information on clinical trials at Texas A&M University's College of Veterinary Medicine, go to vetmed.tamu.edu/clinical-trials.

While cancer in pets can be extremely stressful for owners, the good news is that with the amount of resources and specialists that are now available to treat cancer in pets, owners now have the power to make informed and responsible decisions to get their beloved pets through this illness.

About Pet Talk

Pet Talk is a service of the College of Veterinary Medicine & Biomedical Sciences, Texas A&M University.
Stories can be viewed on the Web at http://tamunews.tamu.edu/.

Suggestions for future topics may be directed to editor@cvm.tamu.edu

Angela G. Clendenin
Director, Communications & Public Relations
Ofc - (979) 862-2675
Cell - (979) 739-5718