Cat Has Cancer: Understanding, Symptoms, and Treatment Options

A cat’s body is a complex system of millions of cells, each playing a vital role in energy production, DNA storage, and essential functions like fighting infections. Normally, these cells follow a cycle of growth, division, and death, replaced by new cells in a continuous process. However, when cells become damaged, they can lose their ability to regulate growth, leading to the development of tumors, which may be cancerous.

Key Insights into Cat Cancer

• Cancer is a significant health concern, affecting approximately 6 million cats in the United States annually.
• The prognosis for a cat with cancer is highly variable, depending on the type of cancer, the extent of its spread, and the cat’s overall health status.
• Even when curative treatment isn’t possible, many cats with cancer can maintain a good quality of life with supportive care. In cases where quality of life declines significantly, humane euthanasia might be the most compassionate option.

What is Cancer in Cats?

Cancer is a prevalent disease in felines. It’s estimated that around 6 million cats in the US are diagnosed with cancer each year. Alarmingly, a significant percentage, between 53% and 83% of tumors found in cats are malignant, meaning they are cancerous and have the potential to spread. Understanding that a Cat Has Cancer is the first step towards providing the best possible care. The outcome for a cat diagnosed with cancer is heavily influenced by several factors, including the specific type of cancer, whether it has metastasized (spread to other parts of the body), and the cat’s general health condition.

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Types of Cancer Affecting Cats

Cats are susceptible to a wide range of cancers. Here are some of the most common types of cancer in cats:

• Lymphoma: This is the most frequently diagnosed cancer in cats. Lymphoma affects lymphocytes, a type of white blood cell crucial for the immune system. These cells are part of the lymphoid tissue found throughout the body, but lymphoma commonly affects the gastrointestinal (GI) tract, kidneys, and lymph nodes in cats.
• Mast Cell Tumors (Mastocytomas): These tumors originate from mast cells, which are produced in the bone marrow and circulate throughout the body, playing a role in allergic responses. In cats, mastocytomas most often develop in the skin or spleen.
• Leiomyosarcoma: A less common but highly painful soft tissue sarcoma, leiomyosarcoma affects the smooth muscles, often found in the stomach and intestines of cats.
• Fibrosarcoma: This type of cancer affects soft tissues like muscle and connective tissue. While it tends to spread slowly, fibrosarcoma can be locally aggressive, meaning it can invade surrounding tissues.
• Mammary Tumors: These tumors develop in the tissue surrounding a cat’s teats. Mammary tumors are typically aggressive and have a high tendency to spread to regional lymph nodes and the lungs.
• Osteosarcoma: This is a bone cancer that impacts the skeletal system of cats. Osteosarcoma is known for being locally aggressive and causing significant pain.
• Ceruminous Gland Adenocarcinoma: This cancer arises in the sweat glands of the ear canal in cats. It’s a type of tumor that specifically targets these glands.
• Melanoma: Melanomas often appear as isolated, raised masses that are prone to bleeding. These tumors can occur in various locations, including the mouth, skin, and eyes of cats.
• Myeloproliferative Neoplasm: This is a category of blood cancers that start in the bone marrow, affecting the production of blood cells.
• Squamous Cell Carcinoma (SCC): SCC is the most prevalent type of skin tumor in cats. It is characterized by rapid growth and can be particularly aggressive.
• Hemangiosarcoma: A fast-growing and dangerous tumor that originates from the cells lining blood vessels. Hemangiosarcoma can lead to internal bleeding due to its origin in blood vessels.
• Transitional Cell Carcinoma (TCC): TCC is a tumor that develops in the bladder of cats. It’s known for being locally aggressive and can cause urinary issues.
• Uterine Cancer: Cancer of the uterus is rare in cats and typically affects older females. Treatment usually involves surgical removal of the uterus and ovaries, a procedure known as ovariohysterectomy or spaying.
• Ovarian Tumors: These are also uncommon in cats but have a tendency to metastasize. In some cases, the ovaries may be a site of metastasis from cancers originating elsewhere in the body. Surgical removal of the ovaries is the standard treatment.

Recognizing Symptoms of Cancer in Cats

The symptoms of cancer in cats can vary widely depending on the type and location of the cancer. It’s crucial to be vigilant and observe your cat for any changes that could indicate a health problem. While these symptoms are not exclusive to cancer and can be caused by other conditions, it’s important to consult a veterinarian if you notice any of the following:

• Unexplained weight loss: If your cat is losing weight without any changes in diet or appetite, it could be a sign of underlying illness, including cancer.
• Changes in appetite: Both decreased and increased appetite can be associated with cancer.
• Lethargy or decreased energy levels: A noticeable decrease in your cat’s usual activity level and energy can be a symptom.
• Lumps or bumps: New or growing lumps anywhere on the body should be checked by a vet.
• Persistent vomiting or diarrhea: Chronic digestive issues that don’t resolve with simple treatments warrant veterinary investigation.
• Difficulty breathing or coughing: Respiratory symptoms can indicate cancer in the lungs or chest cavity.
• Changes in urination or defecation habits: This could include straining to urinate, increased frequency, or blood in the urine or stool.
• Non-healing sores or wounds: Sores that don’t heal as expected can be a sign of skin cancer or other issues.
• Pain or lameness: Unexplained pain or limping could be related to bone cancer or tumors affecting nerves or muscles.
• Changes in behavior: Subtle changes in personality or behavior, such as increased hiding or irritability, can sometimes be associated with illness.

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What Causes Cancer in Cats?

The exact causes of cancer in cats are often multifactorial and can be complex. However, several risk factors and associations have been identified:

• Age: The risk of many types of cancer increases with age. Older cats are generally more susceptible to developing cancer than younger cats, though some cancers are more common in younger animals. The age of onset can vary depending on the specific type of cancer.
• Genetics: Genetic predisposition can play a role in some cancers. Certain breeds might be more prone to specific types of cancer, suggesting a genetic component.
• Environmental Factors: Exposure to certain environmental toxins can increase cancer risk.
  • Tobacco smoke: Secondhand smoke is harmful to cats and has been linked to an increased risk of lymphoma and squamous cell carcinoma.
  • Asbestos: Exposure to asbestos, though less common now, is a known carcinogen.
  • UV light: Prolonged exposure to ultraviolet (UV) radiation from sunlight can increase the risk of skin cancers, particularly squamous cell carcinoma, especially in cats with white or light-colored fur and ears.
• Viral Infections: Certain viral infections are strongly associated with specific types of cancer in cats.
  • Feline Leukemia Virus (FeLV): FeLV is a major risk factor for lymphoma and leukemia in cats. Vaccination against FeLV is crucial in preventing infection and reducing cancer risk.
  • Feline Immunodeficiency Virus (FIV): FIV infection can increase the risk of lymphoma and other cancers, although the association is less direct than with FeLV.
• Diet: While direct links between specific dietary factors and cancer in cats are still being researched, maintaining a healthy weight and providing a balanced diet are important for overall health, which can indirectly influence cancer risk.
• Chronic Inflammation: Chronic inflammatory conditions can sometimes increase the risk of certain cancers over time.

Diagnosing Cancer in Cats: What to Expect

If you suspect your cat has cancer, a thorough diagnostic process is essential. Your veterinarian will take a detailed approach to determine if cancer is present and, if so, what type and extent. The diagnostic process typically includes:

1. Medical History and Symptom Review: Your vet will begin by asking detailed questions about your cat’s health history, including any symptoms you’ve observed, when they started, and how they’ve progressed. It’s helpful to keep a record of symptoms and even take photos of any visible masses or changes.

2. Physical Examination: A comprehensive physical exam is crucial. Your vet will check for palpable lumps, assess overall health, and look for any abnormalities.

3. Blood and Urine Tests: Blood tests (complete blood count and biochemistry profile) and urinalysis are standard procedures. These tests can provide valuable information about organ function and overall health, and can sometimes indicate the presence of cancer or its effects on the body.

4. Imaging Tests: Various imaging techniques are used to visualize internal organs and detect tumors:

   • X-rays (Radiographs): X-rays are useful for examining the chest, abdomen, and bones. They can help detect masses, enlarged organs, and bone abnormalities.
   • Ultrasound: Ultrasound provides real-time images of soft tissues and internal organs. It’s excellent for examining the abdomen, heart, and detecting masses or abnormalities in organs.
   • Endoscopy: This involves inserting a small camera into the body (e.g., through the mouth or rectum) to visualize the gastrointestinal tract, respiratory tract, or other areas.
   • Computed Tomography (CT) Scans: CT scans use X-rays and computer processing to create detailed cross-sectional images. They offer excellent detail and are helpful for assessing the extent and location of tumors.
   • Magnetic Resonance Imaging (MRI): MRI uses magnetic fields and radio waves to produce detailed images, particularly of soft tissues, the brain, and spinal cord. MRI is often used for more complex cases or to evaluate specific areas in detail.

5. Tumor Sampling: To definitively diagnose cancer and determine its type, a sample of the tumor is usually needed for microscopic examination:

   • Fine Needle Aspirate (FNA): A minimally invasive procedure where a thin needle is inserted into the tumor to collect cells. These cells are then examined under a microscope (cytology). FNA is less invasive but may not always provide enough information for a definitive diagnosis.
   • Biopsy: A biopsy involves surgically removing a small piece of the tumor tissue. This tissue is then processed and examined under a microscope (histopathology). Biopsies typically provide more tissue and allow for a more accurate diagnosis, including grading and staging of the cancer.

The choice of diagnostic tests will depend on the suspected type and location of cancer, as well as the cat’s overall health and ability to undergo certain procedures, especially those requiring sedation or anesthesia.

Treatment Options for Cancer in Cats

Treatment for cancer in cats is tailored to the individual cat and depends on several key factors:

• Type of Cancer: Different cancers respond to different treatments.
• Stage of Cancer: The extent to which the cancer has spread (staging) is crucial in determining treatment and prognosis.
• Location and Size of Tumor: The tumor’s location and size can influence treatment options, especially surgical approaches.
• Cat’s Overall Health: Pre-existing health conditions and the cat’s general health status will affect treatment choices.

Your veterinary oncology team will develop the most appropriate treatment plan, which may include one or more of the following modalities:

• Surgery: Surgical removal is often the primary treatment for localized tumors that are accessible. Surgery aims to remove the entire tumor and, in some cases, surrounding tissue to ensure complete removal of cancerous cells.
• Chemotherapy: Chemotherapy involves using drugs to kill cancer cells or stop their growth. It’s often used for systemic cancers (like lymphoma, which affects the whole body) or when cancer has spread. Chemotherapy can be administered intravenously (injection) or orally. Veterinary chemotherapy is generally well-tolerated by cats, with fewer side effects than in humans.
• Radiation Therapy: Radiation therapy uses high-energy radiation beams to target and destroy cancer cells. It’s effective for localized tumors that cannot be surgically removed or to target residual cancer cells after surgery.
• Immunotherapy: Immunotherapy is a newer approach that aims to boost the cat’s own immune system to fight cancer cells. While still evolving in veterinary medicine, it shows promise for certain types of cancer.
• Photodynamic Therapy: This therapy combines light and a light-sensitive drug to destroy cancerous tissue. The drug is activated by light, leading to the destruction of cancer cells.
• Targeted Therapy: Targeted therapies are drugs that specifically target molecules involved in cancer cell growth and survival. This approach is more precise than traditional chemotherapy and may have fewer side effects.
• Palliative Care: When curative treatment isn’t possible or chosen, palliative care focuses on managing symptoms, alleviating pain, and maintaining the cat’s quality of life for as long as possible. This can include pain medication, anti-nausea drugs, nutritional support, and other supportive measures.

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Often, a combination of treatments is used to achieve the best outcome. For example, surgery to remove a tumor may be followed by chemotherapy or radiation therapy to target any remaining cancer cells.

Recovery and Management After Cancer Treatment

Recovery and management after cancer treatment are crucial for your cat’s well-being. The recovery process and timeline will vary depending on the type of treatment, the cat’s overall health, and individual factors. Here’s how you can support your cat during recovery:

• Provide a Quiet and Comfortable Space: Set up a calm, enclosed space for your cat to rest and recover. Ensure they have easy access to fresh water, food, a comfortable bed, and a litter box.
• Close Monitoring: Carefully observe your cat for any signs of complications, such as infection, pain, changes in appetite or behavior, or side effects from treatment.
• Assist with Needs: Help your cat with grooming, eating, and drinking if they are weak or have difficulty performing these tasks themselves.
• Follow Veterinary Guidelines: Strictly adhere to all instructions provided by your veterinarian, including medication schedules, dietary recommendations, and wound care.
• Keep Follow-up Appointments: Regular follow-up appointments are essential to monitor your cat’s progress, detect any recurrence of cancer, and manage any long-term effects of treatment.

Even if your cat is not a candidate for aggressive cancer treatment, maintaining a good quality of life is still possible. Palliative care and supportive measures can help manage symptoms and ensure your cat remains comfortable and happy. However, it’s important to be aware of your cat’s quality of life. If it begins to decline significantly despite supportive care, humane euthanasia may be a compassionate consideration to prevent prolonged suffering. Your veterinarian can guide you through this difficult decision.

Preventing Cancer in Cats: Reducing the Risk

While not all cancers are preventable, there are steps you can take to reduce your cat’s overall risk of developing cancer:

• Minimize Exposure to Toxins:
  • Avoid Tobacco Smoke: Do not smoke around your cat. Secondhand smoke is a known risk factor for feline cancer.
  • Reduce Exposure to Indoor Toxins: Minimize your cat’s exposure to potential toxins like asbestos and certain chemicals.
• Limit UV Light Exposure: For cats with white or light-colored fur, especially on their ears and nose, limit prolonged sun exposure, particularly during peak UV hours, to reduce the risk of skin cancer.
• Vaccination Against FeLV: Vaccinate your cat against Feline Leukemia Virus (FeLV). FeLV vaccination significantly reduces the risk of FeLV infection and associated cancers like lymphoma.
• Regular Veterinary Check-ups:
  • Annual Exams for Young Adults: Schedule yearly wellness exams for cats up to 8 years old.
  • Biannual Exams for Older Cats: For cats older than 8 years, biannual (twice-yearly) exams are recommended. Regular check-ups allow for early detection of health issues, including cancer, increasing the chances of successful treatment.
• Healthy Lifestyle: Maintain your cat at a healthy weight through proper diet and exercise. A strong immune system and overall good health can help the body defend against diseases, including cancer.

Cancer in Cats: Frequently Asked Questions

How long can a cat live with cancer?

The lifespan of a cat after a cancer diagnosis is highly variable. It depends on numerous factors, including the type of cancer, stage at diagnosis, treatment received, and the cat’s overall health. Some cats may only live for a few days or weeks after diagnosis, especially with aggressive or advanced cancers. However, with treatment, some cats can live for months or even years with a good quality of life. Early detection and appropriate treatment are key factors in improving prognosis and extending survival time.

References

Corp-Minamiji C. Cancer is a Cellular Delinquent. Veterinary Partner. March 9, 2015.

Warning signs of cancer. Cornell University College of Veterinary Medicine. Accessed February 18, 2024.

References

WRITTEN BY

Charlotte Hacker, PhD

Freelance Writer