Home » Pet Health » Cancer 101 » Signs and Symptoms to Watch For in Cats


Although a cancer diagnosis in your cat can be upsetting, early discovery can provide your cat with a good quality of life. Cats are very good at masking their symptoms, but there are some early signs of cancer to look for to help you detect the disease. If any of the clinical signs below appear in your cat, do not hesitate to consult your vet.

    1. Excessive hiding: All cats like a good hiding spot. However, if your cat hides for hours at a time, does not come out even for meals, and hides in places that are hard to reach, something might be wrong. This behavior might not indicate cancer, but if a social cat suddenly becomes withdrawn, this unusual behavior requires the attention of a vet.
    1. Weight changes (gain or loss): If your cat experiences a sudden weight loss unrelated to a change in diet or exercise, consider visiting the vet. It may be nothing, but a growth in the gut or the gastrointestinal tract can affect the ability of your cat to digest food properly. Similarly, a mass in the mouth will make eating difficult. Each situation will eventually lead to weight loss. Weight gain, on the other hand, can be a result of something else. For example, a growth in your cat’s digestive tract may cause bloating. If there appears to be rapid weight gain, consider it suspicious and visit the vet, just to be sure.
    1. Mouth changes: Most pets have a natural odor in their mouths, and a change in odor can go unnoticed for long periods. If your pet suddenly develops a particularly unpleasant mouth odor, it may suggest that something unusual is going on. Sores, lesions, scratches, lumps, or wounds in the mouth (particularly those that do not heal) can cause changes in the odor. Excessive drooling can also be a sign that something is up. A check-up with the vet can help alleviate any concerns or explain why your cat is experiencing these changes in the mouth.
    1. Nose changes: Make note of any changes in the coloration and texture of your cat’s nose and bring them to a vet’s attention. If your cat is having nosebleeds, have the vet check your pet, even if the bleeding stops on its own.
    1. General pain or discomfort: Most cats like to snuggle, but if a cat who likes physical attention starts wincing or crying during a petting session, it may be in pain due to an injury or illness. To find out the source of your cat’s discomfort, have your vet examine it.
    1. Skin changes: Make it part of your weekly routine to examine every lump, bump, rash, or lesion on your pet’s skin while you are petting and grooming them. If you notice a skin change that remains for an extended period, do not delay in taking your cat to the vet.
    1. Discharge: Unusual discharge from the eyes, nose, mouth, ears, vulva, vagina, or anus is a cause for concern. Odorous discharge, signs of pain, or bleeding may indicate an infection. Therefore, it’s important to arrange a visit with your vet to have your cat seen as soon as possible.
    1. Change in bathroom habits: Cats are quite regular with their bathroom schedule and generally keep the litter box neat and tidy, but it is still important to keep track of their bathroom habits. If you notice any change in urination (e.g., less, or frequent urination), this might indicate issues with the kidneys, bladder, or urethra. If your pet is straining to have a bowel movement, it means that there might be a blockage in the rectal or anal region. Alternatively, loose stool can indicate changes in the gut. Any unusual changes to your cat’s bathroom habits warrant attention from a vet.
    1. Seizures: Seizures in pets can be scary, but they can mean different things. They most often occur in older cats. If there are sudden and uncontrollable bursts of activity or movement like jerking of the limbs or foaming at the mouth, it could mean your pet is having a seizure and requires a visit to the vet immediately. You also want to monitor other unusual behaviors, like biting or scratching the owner or excessive licking and chewing.

Identifying cancer in your cat can be difficult. But taking your cat to the vet for regular health checkups, being aware of your cat’s habits, and noticing subtle changes in their behavior, will help with early cancer detection. Being attentive to your cat will ensure that your furry friend stays happy and healthy longer.

The Pet Cancer Foundation’s Website Editorial team is comprised of veterinarians, veterinary oncologists, and veterinary technicians, as well as scientific writers and editors who have attained their PhD’s in the life sciences, along with general editors and research assistants. All content found in this section goes through an extensive process with multiple review stages, to ensure this extended resource provides pet families with the most up-to-date information publicly available.

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Last Updated: October 15, 2022

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The Pet Cancer Foundation’s medical resource for pet owners is protected by copyright.

For reprint requests, please see our Content Usage Policy.