Medical:Treating canine cancer

Many people consider cancer to be a human affliction, but the disease can affect dogs, as well. In fact, the American College of Veterinary Medicine reports cancer is the leading cause of disease-related death in older dogs, killing about half those over 10. Canine melanoma accounts for 7 percent of malignant tumors in dogs.

Unlike humans, canine melanoma of the skin tends to be benign. However, researchers estimate 56 percent of canine melanomas develop in the mouth area and most of these tumors are malignant. Some potential warning signs include: a dark, raised mass in the mouth, facial swelling, difficulty swallowing or eating, drooling, bad breath or odor from the oral cavity, mouth bleeding and/or tooth loss.

Since many pet owners don’t regularly examine a dog’s oral cavity, oral melanomas often go undetected until they have advanced. This cancer tends to be very aggressive and can quickly spread to other areas of the body, like the liver, lung or kidneys. Even after surgery to remove the original tumor, median survival time for dogs with advanced oral melanoma is less than 5 months.

One animal cancer treatment currently under study is the canine melanoma vaccine. The vaccine is produced using human tyrosinase, a protein on melanoma cells. Jennifer Baez, V.M.D., Veterinary Oncologist with the Center for Animal Referral and Emergency Services in Langhorne, PA, says, ideally, the non-canine version will train the dog’s immune system to recognize tyrosinase on melanoma cells as different from the protein on normal cells. If that happens, the dog’s immune system may mount an attack against the cancer.

The canine melanoma vaccine is intended for dogs with stage II or III oral melanoma that have been treated and achieved local control of the disease. The vaccine is administered through air-jet injection (no needles). Initially, four biweekly doses are given, followed by booster injections every six months.

According to manufacturer studies, a dog with stage III or IV oral melanoma receiving surgery and/or radiation therapy normally has a median survival time of less than 60 to 90 days. However, for dogs given the canine melanoma vaccine, the median survival time was extended to 389 days.