Pets are diagnosed with cancer at roughly the same rate as people, so many animal lovers will likely experience the terrible heartbreak of losing a beloved companion to this dreadful disease. As in humans, many cancer types occur in pets. Cancer is not always a death sentence, however; if caught early enough, some cancers can be cured, while others can be successfully managed for months or years. With the advancements in chemotherapy and radiation protocols for pets, a positive prognosis is possible. 

Regardless of your pet’s cancer type, any cancer diagnosis will leave you worried, overwhelmed, and confused about your furry friend’s journey. Arming yourself with knowledge about the most common pet cancer types, signs, and treatments will help. 

Most common feline cancers

As our feline friends live longer lives, they are more prone to developing cancer in their later years. Cats commonly live to 20 years of age or older, so they’re at a higher risk for diseases such as cancer, kidney failure, and hyperthyroidism in their golden years. Look for signs of the following most common feline cancers:

  • Lymphoma — The most common type of cancer to affect cats, lymphoma develops in specific blood cells—lymphocytes. Lymphocytes make up the lymphoid tissue, which is found throughout the body, meaning that lymphoma can develop in the gastrointestinal tract, liver, kidneys, spleen, or a variety of other body areas. Cats who harbor the feline leukemia virus are at a much higher risk for developing lymphoma. Multiple medications are available for combating this cancer.

  • Squamous cell carcinoma — This form of skin cancer accounts for a large percentage of all feline skin tumors, as squamous cells are the cells that form your cat’s skin and line her respiratory and digestive tracts. Light-colored or unpigmented cats, and particularly white cats who enjoy lying on sunny windowsills, are more likely to be affected with squamous cell carcinoma. Tumors appear on the hairless areas around the eyelids, ears, and nose, but can also develop inside the mouth because of secondhand smoke. Pet owners who smoke indoors allow smoke to deposit on their pet’s fur, which is then groomed and ingested, and may cause cancer. If possible, surgical removal of the tumor is recommended, followed by chemotherapy.

  • Mammary cancer — Mammary cancer tends to develop in older female cats, and is rare in males. Approximately 85% of all feline mammary tumors are malignant, and they metastasize rapidly. Spaying your cat before her first heat cycle significantly lessens her mammary cancer risk later in life. Surgery is recommended, followed by chemotherapy.

  • Fibrosarcoma — An aggressive tumor that develops from fibrous connective tissue, either in the body or subcutaneous tissue, fibrosarcoma is also slow to metastasize. Surgical removal of the tumor and chemotherapy is required in many cases, as these tumors can grow back.

Most common canine cancers

Cancer is the leading cause of death in dogs over age 10, but can affect younger dogs as well. Keep an eye out for the following most common forms of canine cancer:

  • Lymphoma — Lymphoma has many different types, but is similar to non-Hodgkin’s lymphoma in people. Each variety has a unique set of signs, making an accurate diagnosis critical for effective treatment.

  • Mast cell tumors — A form of skin cancer, mast cell tumors can also develop in internal organs. Mast cells, which react during allergic reactions, are responsible for histamine release. The tumors tend to pop up almost overnight, and should be removed as soon as possible to prevent metastasis.

  • Osteosarcoma — This painful cancer that affects the long bones in dogs, particularly large and giant breeds, can affect not only the leg bones, but also can spread to the lungs and other organs. To battle this extremely aggressive form of cancer, amputation of the affected leg is recommended, followed by chemotherapy.

  • Hemangiosarcoma — A nasty, fast-moving, aggressive form of cancer, hemangiosarcoma attacks the blood vessel walls and can form tumors almost anywhere in the body, but most are found in the heart and spleen. Hemangiosarcoma tumors are most likely to affect golden retrievers, Labrador retrievers, and German shepherds. All too often, hemangiosarcoma is in the advanced stage before diagnosis, requiring dog owners to make quick decisions regarding emergency surgical removal to prevent a rupture and subsequent bleeding, or euthanasia.

  • Melanoma — These common tumors in dogs can be benign or malignant. Benign tumors are often found on a dog’s head, toes, or back, and are usually raised, round masses up to two inches in diameter. Malignant melanomas may be found on a dog’s eye, mouth, or face, and are the most common malignant tumor of a dog’s mouth. Complete surgical removal is required, as chemotherapy and melanoma vaccines have slim success if the melanoma spreads.

Warning signs of cancer

Although cancer is often disguised and not easily detected, watch for the following warning signs:

  • Decreased appetite
  • Weight loss
  • Abnormal masses that suddenly appear or continue to grow
  • Sores that do not heal
  • Abnormal discharge or odor from any orifice
  • Difficulty eating or swallowing
  • Limping, stiffness, or reluctance to move
  • Difficulty breathing, urinating, or defecating

Is your pet not acting quite right? Has her appetite, activity level, or attitude changed? If you note any abnormality in your furry friend’s actions, give us a call, because she needs a thorough diagnostic work-up.