10 Signs of Cancer in Cats: What To Look For and How To Help Your Cat

A cat who has cancer may show little behavioral or physical signs that something is wrong and causing them to feel unwell. While each cat is different, as is their cancer, a few signs can help give clues about your cat’s condition.  

Knowing these signs can help in finding a tumor and getting a diagnosis of cancer. Such early detection is key in improving your cat’s outcome.  

Any signs of cancer may be cause for concern, and your cat should be seen by a veterinarian right away if you notice any of them. 

Let’s look at the most common signs of cancer in cats. 

What Is Cancer in Cats?

Each cell in your cat’s body holds their genetic code, or DNA. This DNA is constantly being copied to make new cells as older ones naturally die off.  

Sometimes this process doesn’t go as planned, and the checkpoints that usually control cell growth and death start to get mixed messages. This can result in very fast and abnormal cell growth, leading to a tumor.  

Some of these masses may be made of cells that are non-cancerous (benign) while others may be made up of cells that are cancerous (malignant).  

The most common types of feline cancer include lymphoma, squamous cell carcinoma (SCC), fibrosarcoma, and mammary tumors.  

A cat’s cancer prognosis depends on several factors, including cancer type, how aggressive it is, the animal’s overall health, and whether the cancer has metastasized, or spread. 

10 Signs of Cancer in Cats

There are many cat cancer symptoms, all of which may vary based on cancer type as well as your cat’s overall health and general mood or personality. 

1. Weight Loss 

Rapid or unintentional weight loss can be a sign of serious illness, including cancer.  

For example, tumors may make it difficult for your cat to eat, can interfere with the absorption of nutrients, and may increase the overall metabolic load on a cat’s body. 

If your cat is diagnosed with cancer, your vet may recommend a veterinary diet specifically for feline cancer patients.

2. Loss of Appetite 

Tumors may release chemical signals, or hormones, that decrease hunger.  

Cats may eat significantly less than usual, may become pickier about the foods they eat, or may go for long periods of time without eating. 

3. Lethargy 

It’s OK for your cat to be tired, but lethargic cats are cause for concern.  

Consistent lack of energy can be a sign of a large strain on the body. You may notice that your cat is less active than usual, seems drowsy, or is uninterested in what’s going on around them. 

4. Lumps and Bumps 

Lumps and bumps can be highly variable due to their many causes. Some are relatively harmless, such as a small fatty deposit that appears as a cat ages. Other lumps and bumps can be much more serious, such as a cancerous tumor.  

Cancerous tumors on cats are often raised, firm or lobular, or pigmented, and may appear to be dead tissue, ulcerated, or inflamed.  

Grooming your cat regularly with a cat brush will help you keep track of any new lumps or bumps that may arise.

5. Difficulty Breathing 

Cancer can put a heavy burden on your cat’s body, causing other functions to become less efficient. Your cat may struggle to breathe, depending on the overall effect of cancer on their body, as well as its location.  

For example, a tumor in the lungs may directly affect your cat’s respiratory function. Coughing, rapid breathing, or unusual breathing patterns are all causes for concern. 

6. Difficulty Urinating and Defecating 

Cancerous tumors can arise anywhere in the body, including the urinary and gastrointestinal tract. A tumor in these areas can cause much discomfort or pain, and it may slow down or block your cat’s ability to pee or poop. 

7. Bloating 

Cancer can cause fluid to be kept and build up in the abdominal cavity, leading to a swollen appearance. 

 Bloating may make your cat feel full and could also contribute to lack of appetite and weight loss. 

8. Poor Healing 

Cancer can take a heavy toll on a cat’s body and cause other processes, such as wound healing, to slow down. Persistent wounds may be a sign of changes to your cat’s immune system because of abnormal cell growth. 

9. Odors 

Cancerous tumors may release volatile organic compounds (VOCs), can cause otherwise healthy tissue to die, and overhaul your cat’s metabolic system, all of which may lead to unpleasant smells.  

Tumors in certain parts of the body, such as the mouth and anus, are more likely to produce noticeable abnormal odors. 

10. Change in Personality 

Cats are known to be stoic creatures who may not show obvious signs of being in pain and physical distress. Even small changes in behavior may be signs of a larger medical issue such as cancer. As their pet parent, any changes in your cat’s behavior must be taken seriously.  

How To Detect Cancer in Cats Early

Early cancer detection is very important to improve outcomes. Regular veterinary checkups and care are some of the best lines of defense in finding cancer in cats early. Young adult cats should have annual exams while cats older than 8 should have exams about every six months.  

Your cat’s veterinarian will do a physical exam and measure your cat’s weight, temperature, pulse rate, and breathing rate.  

Blood work and urinalysis may also be done to check organ function, particularly for older cats. Any abnormal results from these tests may lead to follow-up exams to better understand your cat’s medical status. 

Knowing the signs of cancer in cats as a pet parent can help your vet find feline cancer early.  

Any cat cancer symptoms that are noted outside of regular check-ups are worth a visit to the veterinarian to improve your cat’s prognosis and health outcome.