Skip to content

Common Warning Signs of Cancer in Cats

Here’s a list of the warning signs of cancer in cats that every cat parent should keep an eye on:

🐾 Common Warning Signs of Cancer in Cats

  1. Unexplained lumps or bumps that grow or change in shape.
  2. Weight loss despite eating normally (or even more than usual).
  3. Loss of appetite or refusing favorite foods.
  4. Lethargy or decreased activity; sleeping more than usual.
  5. Difficulty breathing or persistent coughing.
  6. Persistent vomiting or diarrhea.
  7. Changes in litter box habits (straining, urinating outside the box, blood in urine/stool).
  8. Non-healing sores or wounds that won’t close up.
  9. Bad breath (can be a sign of oral cancer).
  10. Swelling or pain in specific areas when touched.
  11. Limping or difficulty jumping (possible bone involvement).
  12. Behavioral changes — hiding more, increased irritability, or clinginess.

🐾 When to See a Vet Immediately

  • Any sudden lump that grows quickly.
  • Unexplained bleeding from the nose, mouth, or rectum.
  • Difficulty breathing or obvious pain.
  • A cat that stops eating or drinking for more than 24 hours.

✅ Bottom line: Not every lump or symptom means cancer — but since cats are good at hiding illness, it’s always safest to get changes checked by a vet early. The earlier cancer is detected, the more options there are for treatment.