Definition of Melanoma
Melanoma is a common, locally invasive and frequently malignant canine cancer that tends to localize in the skin, eyes, nail bed and oral cavity of dogs.
How Melanoma Affects Dogs
Most dogs show no systemic signs of melanoma. The tumors usually are detected either by an owner or by a veterinarian during a routine examination. If the toes are affected, swelling and lameness can occur. Sometimes, cutaneous melanoma will look like a raised sore. Melanoma can be benign or malignant and is diagnosed most frequently in elderly animals. In dogs, melanomas of the skin are usually but not always benign and typically appear as isolated, raised, dark masses. Nail bed melanomas are locally invasive and moderately metastatic. Oral melanomas are invasive, aggressive and extremely metastatic.
Cause of Melanoma in Dogs
The underlying cause of melanoma is not known. This type of cancer arises from abnormal growth of melanin-producing cells. Certain breeds are more commonly affected, suggesting an underlying genetic mechanism for melanoma in companion dogs. Unlike “skin cancer” in people, canine melanoma does not seem to be exacerbated by excessive sun exposure. In fact, dark or black dogs seem predisposed to developing melanoma.
Preventing Melanoma in Dogs
While melanoma cannot be prevented, the adverse effects of this disease can be managed through early detection. Owners should routinely examine their pets for suspicious lumps and bumps. Currently, there is no vaccine which can prevent canine melanoma, although there is a “vaccine” that is licensed to help treat the condition by prolonging survival rates and minimizing clinical signs of disease.
Special Notes
Melanoma should be treated aggressively with surgical removal followed by chemotherapy and/or radiation. The prognosis for dogs with benign skin tumors is excellent. The outlook for dogs with malignant melanoma is guarded to poor.