Melanoma in Dogs and Cats

Melanomas are (usually) malignant tumors that are commonly found on the paws, skin, and in the mouths of dogs and cats. They form in the pet’s melanocytes, the pigmented cells in the skin and other tissues in the body. These tumors tend to grow very rapidly, and in some cases, they will become ulcerated or start to bleed. Melanoma is an aggressive type of cancer that when not treated can quickly metastasize to any part of the body.

Melanomas can be either benign or malignant, and they can affect both dogs and cats equally, although it is seen more in dogs than cats. They can be found on both hairy and hairless patches of skin, and they can be either pigmented or non-pigmented.

Melanoma and Canines

Melanoma can affect any age or breed of dog, but studies suggest that light-skinned dogs are at higher risk of developing it. The reason is because the animal’s low pigment in the skin and hair is more likely to increase the skin’s cellular mutations from ultraviolet light. Meanwhile, studies also indicate that melanoma may be genetic as well, because some breeds seem to be more predisposed to the disease. These breeds include Golden Retrievers, Cocker Spaniels, Gordon Setters, Scottish Terriers, and Chow Chows.

Canines most commonly suffer from melanoma in the mouth and on the toes. When the pet is suffering from oral melanoma, the symptoms can include bad breath, swelling in the face, increased salivation, loose teeth, pain in the mouth, dropping food, and an inability to eat. When the toes are affected, the most common signs are swelling in the toes and limping on the affected leg.

Melanoma and Felines

Melanoma is commonly associated with a cat’s skin, but surprisingly, it is most commonly found in the eyes of felines. It can also just as easily develop on cat’s toes, ears, and mouth.

The truth is, many cats already have melanocytoma, the benign and non-spreading form of the disease. This is identified by little black spots on the lips, eyelids, nose and gums. Usually, cats that have orange, silver, or cream-colored coats have melancytoma.

Melanoma accounts for approximately 2% of all feline tumors. In cases of ocular melanoma, the most common symptoms include a change in eye color, a dark spot at the point where the iris and white of the eye meet, and increased tearing (weeping). Your cat may paw at the eye, and in some cases, the condition can cause pain. In cases of dermal or mouth-related melanoma, the signs and symptoms in cats are similar to those exhibited by dogs.

What to Do if You Detect Symptoms of Melanoma in Your Pet

If you notice signs that your pet may have a form of melanoma or that they are acting differently, schedule an appointment with your veterinarian immediately. Melanoma can spread quickly, so it is important that it be diagnosed and treated as soon as possible.

The veterinarian will perform a thorough exam of your pet, and in most cases, will aspirate the tumor with a fine needle. If the aspiration does not offer conclusive evidence, then a tissue biopsy will usually be performed. A radiograph or CT scan will also usually be ordered to investigate the lungs and lymph nodes for signs of cancer. An abdominal ultrasound may finally be used to look for cancer in the abdominal organs.

How Is Melanoma Treated?

Removal of the tumor is usually the primary treatment for melanoma, especially when it is located in the digits. In cases where the cancer is in the mouth, removing the entire tumor can prove difficult, because it usually invades the bones. As a result, chemotherapy and radiation therapy often play a role in the treatment of the disease.

In dogs, platinum-based chemotherapy drugs like carboplatin or cisplatin tend to be the most commonly administered drugs in cases of melanoma.

Diamondback Drugs offers these and other medications for managing the progression of melanoma in cats and dogs in a variety of pet-friendly formulations.

How to Prevent Melanoma in Your Pet

Due to the unknown causes associated with melanoma, it can be difficult to prevent the disease entirely. In 2010, however, the FDA did approve a DNA vaccine for canine melanoma. In clinical studies, the vaccine showed significant potential for helping dogs with melanoma to live longer lives, even those in the advanced stages of the disease.

If your pet has melanoma, you can talk to your veterinarian about this vaccine. Otherwise, simply helping your pet live a healthy lifestyle is the best advice. This includes:

  • Seeing a veterinarian regularly (at least twice a year, or more if you have a breed of cat or dog that is genetically predisposed to melanoma)
  • Limiting your pet’s exposure to toxic chemicals (antifreeze, pesticides, herbicides, paints and solvents, etc.)
  • Feeding your pet a healthy diet
  • Providing your pet with plenty of fresh, clean water
  • Playing with your pet daily to ensure they get enough exercise
  • Administering veterinarian-prescribed medications exactly as instructed
  • Limiting the amount of time your pet is exposed to direct sunlight

Author: Giano Panzarella