Pets are living longer than ever nowadays, thanks to quality nutrition, proper exercise, and routine preventive care. Yet, with an increased lifespan comes an increased chance for cancer, as well as other age-related diseases. According to the American Veterinary Medical Association (AVMA), approximately one in four dogs will develop cancer, and almost half of all dogs over age 10 will develop neoplasia. Dogs get cancer at roughly the same rate as people, but less information is available about the cancer rate in cats.

Unfortunately, during a lifetime of pet ownership,  your pet may develop cancer. While not every lump and bump that pops up is malignant, you should bring your pet who has a lump to Leawood Plaza Animal Hospital for a thorough physical exam and diagnostic testing, so we can determine its type, and why it appeared, since early diagnosis and treatment are vital. If a fine needle aspirate or biopsy sample reveals that the mass is cancerous, your pet may have one of the following five most common cancers.

#1: Mast cell tumor

Mast cell tumors are the most common skin tumor found in dogs, and most commonly affect older dogs, in particular boxers, Boston terriers, bulldogs, pugs, and Labradors. Mast cells are a cell type associated with allergies and inflammation, and chronic inflammation may play a role in mast cell tumor development. Because they are associated with inflammation, mast cell tumors can vary in appearance, and can be red, ulcerated, hairless, or swollen. Dogs who develop one mast cell tumor are at risk for future growths, despite the first tumor being completely surgically removed. Full tumor excision with wide margins is critical, to avoid regrowth of area cancer cells, and to prevent metastasis. Feline skin mast cell tumors are more benign than the canine form, and can be cured with complete tumor removal.

#2: Osteosarcoma

Osteosarcoma is a common bone cancer that can affect any dog breed, but large and giant breeds are at the highest risk. Size, particularly height, is more important than breed, and osteosarcoma is commonly found in tall, leggy dogs, such as the Irish wolfhound, Scottish deerhound, and Great Dane. Osteosarcoma is an excruciating cancer that destroys the bone and the surrounding soft tissue, so many pets feel great relief after amputation of the affected limb. 

Osteosarcoma is rare in cats, and less aggressive than the canine form, growing more slowly, and less likely to metastasize. 

#3: Melanoma

Melanoma is the most common malignant oral tumor found in dogs, and is highly locally invasive, meaning that significant damage occurs at the site of origin, destroying the jawbone and support of associated teeth. While no particular breed seems prone to oral melanoma development, pets with darkly pigmented gums and lips are predisposed to malignant melanoma. In cats, dermal melanomas are rare, but 50% are malignant.

#4: Lymphoma

Lymphoma is a cancer of a blood cell—lymphocytes—and lymphoid tissues. Lymphoid tissue is found in many body areas, such as the lymph nodes, spleen, liver, gastrointestinal tract, and bone marrow, and its clinical signs are equally as varied. Although a common cancer in dogs and quite aggressive if left untreated, lymphoma often responds well to treatment, adding months to years to the dog’s life. 

In cats, lymphoma is the most commonly diagnosed malignant disease. Lymphoma in young cats often follows infection from feline leukemia or feline immunodeficiency virus. Older cats typically suffer from intestinal lymphoma, which can lead to vomiting, diarrhea, and weight loss. 

#5: Squamous cell carcinoma

Squamous cell carcinoma commonly affects cats in cutaneous or oral form. White or light-colored cats are most at risk for contracting cutaneous squamous cell carcinoma, which develops on the face or ears in particular, but can also develop anywhere that is exposed to sunlight for long periods of time. Squamous cell carcinomas on the skin appear as a red, thickened area, or a scab, and prognosis is usually excellent with small lesions, after surgery or radiation therapy.

Cats who live in households with a smoker can develop oral squamous cell carcinoma from grooming the second-hand smoke carcinogens off their fur. Like other oral tumors, oral squamous cell carcinomas are aggressive, locally invasive, and difficult to control, appearing as large, painful masses that are often ulcerated. 

Pet oncology is a varied, complex aspect of veterinary medicine, and new research is continuously being published as advancements are made. If your pet develops any cancer type, there is still hope, with a prompt diagnosis and treatment plan.

If you notice a suspicious lump or bump on your furry pal, call us to schedule an appointment. Early diagnosis and treatment are key for a positive prognosis.