My Pet Demand

Created: March 11, 2026

how to tell if your cat has cancer

Did you know that about 32% of cats over the age of ten die because of cancer?

Cancer is an uncontrolled growth of cells and can affect any part of your kitty’s body. There are many types of cancers in cats. Usually, most of them start small as a bump or a lump on the body. 

If left unchecked, cancer can spread across your cat’s body. 

So, how do you know if your cat has cancer?

In this blog post, we’ll go through everything you need to know about cancer in cats and answer common questions like, “how to tell if your cat has cancer?”, “how do cats get cancer?” and more.

What Is Cancer in Cats? 

Cancer in cats is not different from cancer in dogs or human beings. 

Cancer has to do with your cat’s cells. Cells have a lifespan of their own, which means as old cells die, new ones are created by your cat’s body to replace them. 

Now, in cats with cancer, the new cells grow faster in number. This means that they’re not just replacing the old dying cells. They go out of control, damaging your cat’s tissues and organs. 

So, how to know if your cat has cancer?

What Causes Cancer in Cats? 

One of the most common questions we come across is, “How do cats get cancer?” The causes of cancer in cats, for the most part, remain unknown. 

Experts have their theories.

  • Genetic: Experts believe that some cancers are hereditary in nature. This means that they are passed in from one generation to the next. 
  • Environmental: This has to do with your cat’s diet and lifestyle. A bad diet may increase your cat’s chances of getting cancer. Other environmental causes include exposure to radiation, inhaling tobacco smoke, etc. 

How Common is Cancer in Cats? 

We only have data about cancer in household cats. So, it may not be 100% accurate since we don’t have a lot of data about wild cats.

Studies show that three in ten cats over the age of ten years die of cancer. 

In fact, did you know that cancer rate in pets is parallel to the rate in humans? Some believe that the number of pets with cancer has sky-rocketed due to the commercial pet food industry, environmental toxins, and carcinogens. 

Some Common Cancers in Cats: How Do You Know If Your Cat Has Cancer? 

In this section of the blog post, we’d like to go through four of the most common cancers in cats and their causes.

This will help you determine the type of cancer your kitty might have. 

1. Lymphoma

The lymphatic system is an important part of your cat’s immune system. It maintains the flow of fluids in your cat’s body and clears it of toxins. So, Lymphoma is a form of blood cancer. 

2. Bone Cancer 

This is an aggressive form of cancer and common in giant breeds. The symptoms include lethargy, lameness, and swelling in the affected area. Kitties with bone cancer are in a lot of pain. 

3. Squamous Cell Carcinoma

This type of cancer is a result of second-hand smoking. The Squamous cells form your kitty’s skin. It manifests itself as sores in your cat’s mouth, bad breath, sores on the skin, etc. 

4. Mast Cell Tumors 

These white blood cells start multiplying to form abnormal swellings on your cat’s body. While some of them are benign, others are malignant. This type of cancer is common in Siamese cats. 

Now, let’s take a look at how to tell if your cat has cancer.

Common Signs and Symptoms: How Do You Know if Your Cat Has Cancer? 

Let’s take a look at some common telltale signs that your cat has cancer. 

Watch this video if you have the time!

1. Weight Changes

Unexplained changes to your cat’s weight should always be a red flag. 

This includes weight loss as well as weight gain. 

Some cats with cancer lose weight even though there are no changes in food or activity. Rapid weight loss is something you need to look into as soon as possible. 

With some forms of cancer, cats actually start gaining weight–especially when there’s an internal tumor involved. So, if your kitty seems heavier than before, pay the vet a visit to see what’s going on. 

2. Changes in the Mouth 

Changes in the color of your cat’s gums, unexplained bleeding, sores, lumps, and a strange odor coming from your cat’s mouth–all point to cancer. This is one of the signs that go unnoticed the longest. 

Keep an eye on your kitty’s mouth while brushing her teeth to ensure everything is a-okay. 

3. Frequent Nosebleeds 

While nosebleeds may be relatively common in humans, they aren’t in cats. Nosebleeds are a sign that something’s wrong. If your cat has frequent nosebleeds, you should consult your vet as soon as you can. 

4. Changes in the Skin 

Changes to your cat’s skin and fur also point to the possibility of cancer. 

This includes lumps, bumps, and changes to the texture of your kitty’s skin. If you notice a bump on your kitty’s skin, look for redness and swelling. Not every bump on your cat’s body is malignant. However, it’s best to get them checked out. 

Isn’t it? 

5. Lethargy and General Pain or Discomfort 

Has your kitty not been her active self lately? 

If your cat has been lethargic and has been showing signs of pain and discomfort, you need to take her to the vet. Discharge from your kitty’s eyes and nose also points to cancer. 

Moving on.

Some Clinical Signs and Symptoms of Cancer in Cats 

Other than the general symptoms mentioned in the previous section, there are some clinical signs of cancer to look out for as well. 

These include the following:

  • Increased hunger and demands for food even when not on a diet 
  • Stiffness
  • Bad oral odor 
  • Difficulty breathing
  • Coughing 
  • Difficulty in defecating or urinating 
  • Sores on the body that aren’t healing as they normally should 
  • Unexplained discharge or bleeding from the body 
  • Loss of appetite 
  • Changes in bowel and bladder habits 

Diagnosis and Assessment

A formal diagnosis is crucial to determine the type of cancer your cat has and its course. 

It also helps determine the stage of progression your kitty has reached. 

Diagnosing cancer in cats involves the following:

  1. Nuclear scanning to view your kitty’s internal organs like spleen, kidney, liver, lungs, thyroid, and bones. 
  2. Xrays to check for tumors or the bladder, gastrointestinal tract, and lungs. 
  3. Physical examination to check your kitty’s body for sores, lumps, and other symptoms. 
  4. Ultrasound to see the internal organs and diagnose internal tumors. It also helps assess cysts. 
  5. Cytology by taking cells from the growth and checking it for cancer. 

Your vet might need a combination of these assessments to accurately diagnose your kitty with cancer.

A Quick Note on Treatment Options

The treatment options for cats with cancer depend on the type of cancer your cat has, the stage she’s in, and what would work best for her individual case. The treatment usually involves:

  • Surgery 
  • Radiation therapy 
  • Chemotherapy 

Your vet will be best able to recommend the course of treatment you should go for. What works for one cat may not work for the other. So, seek proper medical advice and counsel.

Summing Up: How Do I Know If My Cat Has Cancer? 

Did we answer all of your questions in this blog post? 

Cancer has become increasingly common in cats. Some experts believe that this might be due to improper diet and lifestyle. Of course, cancer has genetic causes as well. 

So, how do you know if your cat has cancer

Several diagnostic tests are required to make an accurate diagnosis. But, signs of cancer include:

  • Unexplained weight loss 
  • Excessive hiding 
  • Nose bleeds
  • Changes in the mouth 
  • Frequent nose bleeds 
  • Changes in your kitty’s bathroom habits 
  • Seizures 
  • Discharge from the eyes or the nose 

If you notice any of these symptoms, contact your vet as soon as possible for a proper diagnosis.

Medical Disclaimer:
The information provided in this article is for educational and informational purposes only and should not be considered veterinary advice. Every pet is unique, and their health conditions, needs, and responses may vary. Before applying any remedies, treatments, or recommendations mentioned in this content, it is strongly advised to consult a qualified veterinarian or animal health professional to ensure they are appropriate and safe for your pet.

Content Accuracy Disclaimer:
We aim to keep our content accurate and up to date. However, pet care knowledge and veterinary research evolve over time, and we cannot guarantee that all information will always remain current. Please consult a qualified veterinarian for professional guidance regarding your pet’s health.