Can Cats Get Cancer? Understanding Common Feline Cancers Like Lymphoma, SCC, and More

Last updated:
June 11, 2024
Old cat sleeping on a floor

Did you know that our feline friends can suffer from cancer just like humans? As heartbreaking as it sounds, cancer is a common reality for many cats, affecting an estimated one in five during their lifetime. From the silent but aggressive cat lymphoma to other prevalent forms like squamous cell carcinoma or mammary cancer, understanding these diseases is crucial for early detection and treatment. In this post, we’ll delve into the most common cancers in cats, their symptoms, and what you can do to protect your beloved pet.

Cancer in cats 

Cancer is a complex and varied disease, but at its core, it involves the uncontrolled growth of cells. In a healthy body, cells grow, divide, and die in a regulated manner. This process ensures that new cells replace old or damaged ones, maintaining the body's overall health and function. However, when this regulation breaks down, cells begin to grow and divide uncontrollably. These abnormal cells can form masses known as tumors, which can be benign (non-cancerous) or malignant (cancerous). Malignant tumors are particularly dangerous because they can invade nearby tissues and spread to other parts of the body through the bloodstream or lymphatic system, a process known as metastasis.

Cancer is not just a human affliction; it affects our beloved pets as well. In fact, cancer is one of the leading causes of death in older cats. According to veterinary oncologists, approximately one in five cats will develop some form of cancer during their lifetime.1 This statistic highlights the significant impact of cancer on the feline population and underscores the importance of awareness and early detection.

While there are many things that can potentially contribute to a cat having cancer, there is no one way to know whether your cat will be the one in five or not. The many factors include: age, genetic predisposition, environmental factors (for example: being in a home with a smoker), and the difference of being an indoor or outdoor cat. 

Understanding the prevalence and risk factors of cancer in cats is crucial for early detection and prevention. Regular veterinary check-ups, a healthy diet, and minimizing exposure to carcinogens are thought to reduce the risk of cancer and ensure that any signs of cancer are caught early. Early detection can significantly improves the chances of successful treatment, making it possible for many cats to lead longer, healthier lives even after a cancer diagnosis.

Commonly Diagnosed Cancers in Cats

Lymphoma is a cancer of the lymphatic system, which includes the lymph nodes, spleen, and other organs involved in immune function. It is the most common cancer in cats, accounting for approximately 30% of all cat cancer diagnoses,3 which is a significant percentage of feline cancer diagnoses. Lymphoma can affect various parts of the body, including the gastrointestinal tract, chest, lymph nodes, skin, nervous system, and kidneys to name a few. Cats infected with the feline leukemia virus (FeLV) or feline immunodeficiency virus (FIV) are at higher risk for developing lymphoma.

You can read more about cat lymphoma and the impact it has on your cat at our blog here. 

Symptoms of cat lymphoma can vary depending on the affected area but commonly include:1

  • Weight Loss: Unexplained weight loss despite a normal or reduced appetite.
  • Lethargy: Decreased energy levels and increased sleeping.
  • Loss of Appetite: Reduced interest in food or complete refusal to eat.
  • Swollen Lymph Nodes: Noticeable swelling in the lymph nodes, particularly under the jaw, in front of the shoulders, or behind the knees.

Treatment for cat lymphoma often involves chemotherapy, which can be effective in prolonging a cat's life and improving their quality of life. The specific treatment protocol depends on the type and stage of lymphoma. Some cats respond well to chemotherapy and can achieve remission, while others may require additional supportive care to manage symptoms and maintain comfort.4 

Learn more about treatment options for cat lymphoma in our post here. 

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is a common type of cancer that affects the skin and mucous membranes of cats. This malignant tumor arises from the squamous epithelial cells, which are found in the outer layers of the skin and the lining of various organs. SCC is particularly prevalent in areas exposed to the sun, such as the nose, ears, and eyelids, making it a significant concern for cats with light-colored fur or those that spend a lot of time outdoors. Additionally, SCC can occur in the mouth, particularly on the gums, tongue, or tonsils, and is one of the most common oral cancers in cats. SCC which develops in the mouth has nothing to do with sun exposure and can occur in any cat.

The symptoms of squamous cell carcinoma can vary depending on the location of the tumor. Common signs to watch out for include2:

  • Non-healing sores or ulcers: Persistent wounds or sores that do not heal, especially on the nose, ears, or other sun-exposed areas.
  • Oral symptoms: In cases of oral SCC, symptoms may include bad breath, drooling, difficulty eating or swallowing, and oral bleeding.
  • Skin lesions: Raised, red, or scaly patches on the skin that may bleed or become infected.
  • Swelling or masses: Any unusual lumps or bumps on the skin or in the mouth.

The treatment of squamous cell carcinoma in cats typically involves a combination of surgical and non-surgical approaches. Non-surgical approaches can include radiation therapy, either in conjunction with surgery or on its own; cryotherapy, using extreme cold to destroy the cancer cells; or chemotherapy for some particularly advanced cases, though it’s not a common option. SCC on the skin and mucous membranes is generally not as aggressive and responds well to treatment. Sadly, oral SCC is very aggressive and often has a minimal response to any therapy.4

Mammary (Breast) Cancer

Mammary (breast) cancer is a significant health concern in female cats, particularly those that are not spayed. The risk of developing mammary tumors is markedly reduced in cats that are spayed before their first heat cycle, making early spaying a crucial preventative measure. Mammary tumors can be benign or malignant, although malignant tumors are those that are more aggressive and can spread to other parts of the body.

Symptoms of mammary cancer in cats include:

  • Lumps in the breast tissue: The most common sign is the presence of small, firm lumps or masses in the mammary glands. These lumps can vary in size and may be singular or multiple.
  • Swelling: Swelling or enlargement of the mammary glands, which can be accompanied by pain or discomfort.
  • Discharge: Any abnormal discharge from the nipples, which may be clear, bloody, or pus-like.
  • Ulceration: In advanced cases, the skin over the tumors may become ulcerated, leading to open sores.

Treatment for mammary cancer typically involves surgical removal of the tumors. This may range from removing the affected gland (lumpectomy) to more extensive surgery, such as a mastectomy, where one or more mammary glands are removed. Surgery is often followed by chemotherapy to target any remaining cancer cells and reduce the risk of recurrence.


Fibrosarcoma is a type of cancer that arises from the fibrous connective tissues, which provide structural support to various parts of the body. This malignant tumor is known for its aggressive nature and tendency to invade surrounding tissues. While fibrosarcomas can develop in many different locations, they are commonly found in the skin, mouth, and at injection sites, leading to a subset of the cancer known as vaccine-associated fibrosarcoma. This cancer predominantly affects middle-aged to older cats but can infrequently occur in younger cats, as well.

The symptoms of fibrosarcoma can vary depending on the tumor's location but generally include:

  • Lumps or Masses: A noticeable lump or mass under the skin, which may grow rapidly and feel firm or fixed to underlying tissues.
  • Swelling: Swelling in the affected area, which can be painful or cause discomfort.
  • Ulceration: In advanced cases, the skin over the tumor may ulcerate, leading to open sores.
  • Oral Symptoms: For tumors in the mouth, symptoms may include difficulty eating, drooling, bad breath, and bleeding.

Treatment for fibrosarcoma often involves a combination of surgical and non-surgical approaches. Post surgery, non-surgical approaches typically include radiation therapy to target any remaining cancer cells and chemotherapy can be used in some cases to manage the disease,  but this may not be needed for every cat with fibrosarcoma.

The Importance of Regular Vet Visits

Regular veterinary check-ups are crucial for the early detection of cancer in cats. Just as routine health screenings are essential for humans, these check-ups help identify any unusual changes or early signs of disease in cats.1 

Cats are masters at hiding illness, making it even more important for pet owners to rely on professional veterinary evaluations. During these visits, veterinarians can conduct thorough physical exams, looking for lumps, bumps, or any other abnormalities that might indicate the presence of cancer. By catching potential issues early, the chances of successful treatment and management are significantly increased, potentially saving your cat’s life.

Diagnosing Cat Cancers

Common tests used to diagnose cancer in cats include:

  • Blood Work: Blood tests can provide valuable information about a cat’s overall health and detect abnormalities that might suggest cancer. For example, changes in blood cell counts can indicate leukemia or lymphoma.
  • X-rays: X-rays help visualize internal structures and identify tumors in organs such as the lungs,or bones. This imaging technique is essential for spotting masses that cannot be detected through a physical exam alone.
  • Ultrasound: Ultrasound uses sound waves to create detailed images of internal organs. It is particularly useful for examining the abdomen and identifying tumors in organs such as the liver, spleen, and kidneys.
  • Biopsy: A biopsy involves taking a small sample of tissue from a suspicious area to be examined under a microscope. This is the most definitive way to diagnose cancer, as it allows for the identification of cancerous cells.5
  • Fine Needle Aspiration: This less invasive procedure involves using a thin needle to extract cells from a lump or mass for microscopic examination. This is the most common way to diagnose cat lymphoma.

By utilizing these diagnostic tools, veterinarians can accurately diagnose cancer in cats, determine the type and stage of the disease, and develop an appropriate treatment plan. 

ImpriMed helps veterinarians get the most confident diagnosis for feline lymphoma.

If you're worried your cat might have lymphoma or isn't feeling quite right, we're here to help with tests that are precise and reliable, like having a trusty sidekick in your cat's healthcare adventure.

ImpriMed helps pet parents make the best decisions for their pet’s lymphoma journey, find out more about what we do here.

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