The incidence of cancers and tumors in cats is on the rise. There are a variety of cancerous masses that can affect cats, and the discovery of a mass should always cause for concern.
As they age, dogs have a high likelihood of developing lipomas, tumors beneath the skin made of fat deposits. Many dogs will develop an array of lipomas as they age, but most of these tumors are benign, and they often do not even necessitate removal, so long as they are not causing pain or discomfort to the dog. Unfortunately, lipomas are not nearly as common in cats as they are in dogs, and if you feel a lump or odd swelling on your cat, prompt veterinary attention should be sought, as the chance of treating and curing a cancerous mass in your cat is far greater if the problem is caught sooner rather than later.
One of the most common types of cancer in cats is the squamous cell carcinoma, or SCC. This tumor involves the skin, and is most often seen in light colored, or unpigmented skin. The most common locations for SCC are on the nose, eyelids, and tips of the ears. It is most commonly seen in older cats, and those with a white coat or with white tips of the ears and face. Exposure to direct sunlight, such as in outdoor cats, is frequently attributed to the cause of SCC.
Signs of SCC in a cat may include small ulcer-like lesions that bleed frequently, and may continue to grow in size. On the nose, the advanced SCC can appear to erode parts of the nose, becoming raw and uncomfortable. A biopsy of the affected tissue is required to ensure presence of squamous cell carcinoma, and depending on results of the biopsy your veterinarian may recommend surgery, or a consult with a veterinary oncologist.
Despite the high rate of occurrence in some cats, squamous cell carcinoma rarely metastasizes to the rest of the body, and treatment to remove the cancerous lesion is usually curative. Surgical excision may be performed if possible, or in some cases cryosurgery or laser surgery may be more effective.
Another commonly seen skin tumor in cats is the Mast Cell Tumor (MCT). Frequently seen on the head and neck, MCT’s can also be found on the body, legs and even in the mouth. Cats may show no signs of severe illness, but the tumor may cause itchiness, and frequently become ulcerated. Mast cell tumors are often very small, the size of a pencil eraser or smaller, and appear as a firm, raised hairless mass, pink or white in color.
Because it is difficult to differentiate visually between mast cell tumors and other benign skin growths such as cysts, any suspicious growth on your cat should be biopsied via a fine-needle aspiration. This procedure takes a sample of the cells within the mass, and a microscopic evaluation will be performed to diagnose the type of mass.
If the tumor is found to be a mast cell tumor, surgical excision is the treatment of choice. Because the mast cell tumor may be much larger under the skin than they appear, wide margins must be taken to ensure the complete removal of the tumor. Unlike in dogs, mast cell tumors have a smaller likelihood of reoccurrence or spread, and surgery is generally curative. However, depending on your cats particular situation, your veterinarian may recommend X-rays to ensure that the tumor has not spread, as well as a consultation with a veterinary oncologist.
Mammary tumors are a cancerous growth that occurs in the breast tissues. Similar to human breast cancer, mammary tumors are a serious problem, and can be fatal. Mammary tumors are the most common cancer of female cats (they can occur rarely in male cats as well) and are especially a concern for older, intact female cats.
The cause of mammary tumors is still not known, though studies have shown that hormones like estrogen are a factor in their development. Cats spayed (ovariohysterectomy) before their first heat cycle have had a reduced exposure to hormones in their life, and have smaller than 1% risk of developing a mammary tumor in their lifetime. However, cats spayed later in life, after several heat cycles or pregnancies, carry a significantly increased risk.
Mammary tumors occur within the mammary gland, and may feel soft or hard under the skin. Some cause bruising of the skin around the mammary gland, and more advanced tumors may cause open wounds in the skin surrounding them, or even bleed. While a full half of mammary tumors are benign, malignant mammary tumors are very aggressive, and can quickly spread to the lymph nodes, lungs and other organs. For this reason, every mammary tumor should be treated as if malignant until proven otherwise.
If you suspect a mammary tumor on your cat, prompt medical treatment should be obtained. Your veterinarian may take a fine-needle aspiration of the tumor, which will be examined to determine the type and seriousness of the tumor. Bloodwork will be performed to access the cats general health, as well as chest X-rays to determine the spread of the disease to the lungs. Your vet may recommend additional tests to get a clear picture as to the health of your cat, and to help decide the best course of treatment for the cancer.
Surgical treatment is done in the form of a mastectomy, removing the mass as well as the associated mammary gland. Surrounding lymph nodes may be removed as well, if it has been determined they are involved. If your cat is intact, a spay procedure may be performed at the same time as the mass removal. Consultation with a veterinary oncologist is also suggested, as chemotherapy or radiation therapy may be recommended, especially if the cancerous cells have spread past the mammary gland.
The prognosis for cats with mammary tumors is varied, and depends greatly on how quickly the cancer was found and treated. In the case of all tumors in cats, the best outcomes are largely associated with the prompt recognition and treatment. If you suspect a tumor in your cat, seeking veterinary care now may significantly improve the outcome of treatment.