Melanoma is a type of cancer that most frequently affects middle-aged or older dogs, especially those with black fur. Certain breeds (e.g., Boston terriers, cocker spaniels, and Doberman pinschers) are also predisposed to developing melanoma. Tumors are frequently located in the mouth, in the skin, and on the toes. Cancer affecting the toes or within the mouth has a tendency to spread aggressively throughout the body, while skin tumors can be either malignant or benign.
Melanomas arise from the cells that darken the skin, but the tumors may be black, brown, or lighter in color. Cancer inside of the mouth often produces a foul odor to an animal's breath, blood-tinged saliva, drooling, and difficulty eating. A veterinarian or veterinary pathologist can diagnose most cases of melanoma by examining a sample of cells or tissue from the tumor under the microscope. Additional tests such as blood work, a urinalysis, and x-rays are performed to get a picture of the pet's overall health and to help plan appropriate treatment.
Treatment for melanoma often starts with surgery to remove as much of the tumor as possible. Toe amputation is the most effective way to deal with cancer affecting this part of the body. In some cases, tumors in the mouth may be treated by removing part of a dog's jaw. Chemotherapy and radiation treatment can also be part of the treatment plan. Recently, a vaccine has been approved that helps tremendously in many cases of oral melanoma. The vaccine stimulates the dog's immune system to destroy cancerous cells and can significantly extend an animal's life expectancy after surgery.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008