Signs of Feline Cancer

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Along with new technologies, medical breakthroughs, and improved levels of care for domestic cats as people place more value on pets, our feline family members are living longer. Long enough in many cases, to develop cancer. While it's worrying when you discover lumps or bumps during routine examinations of your cat's body, advances in diagnostic techniques and treatment make it possible for a cat with early-stage cancer to have a fighting chance of beating it.

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Unpredictable, invasive, and out of control, malignant (cancerous) neoplasms in cats often can grow very rapidly, metastasizing to surrounding tissues and organs in only a couple of months. Early detection of the signs and symptoms of feline cancer make a successful outcome more likely for your beloved feline.

What is cancer?

Cancer starts with neoplasia, which is the abnormal, uncontrolled growth of tissues or cells in the body. The growth itself is called a neoplasm, tumor, or mass, which describes the swollen physical appearance of the neoplasm, and it can be benign (non-cancerous) or malignant (cancerous). If benign, the tumor will grow quite slowly relative to a malignant tumor, and generally does not invade the surrounding tissues or spread throughout the body. Conversely, a malignant tumor grows at various rates, often very quickly, invading the surrounding tissues and spreading, or metastasizing to other parts of the body.


Keep in mind that neoplasia and cancer are not synonymous, but even benign neoplasms can cause health problems, for instance, in the case of a brain tumor, which places pressure on the organ and impairs function.

With, as yet, no known cure, cancer claims the lives of thousands of people and pets every year. In fact, dogs develop cancer at about the same rate as humans. According to the American Veterinary Medical Association, one in four dogs will at some stage of their life develop neoplasia and over half of dogs over the age of 10 will develop cancer, but there's less precise information available about feline cancer.


But one thing is clear; in cats, when neoplasms develop, they have a much higher incidence of malignancy than in dogs — a staggering 85 percent in breast neoplasms, for example. Spaying a female cat before she's a year old may reduce this risk. Cancer is so prevalent in cats, it has become the most common cause of death, according to Cancer Quest, an initiative of the Winship Cancer Institute at the Emory University in Atlanta. Further, lymphoma, cancer that begins in the infection-fighting cells of the immune system, is more common in cats than dogs.

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Is cancer preventable?

Unfortunately, cancer is not a preventable disease and considered multifactorial since there is no known single cause. That being said, hereditary and environmental factors, such as exposure to carcinogens and secondhand tobacco smoke contributes to both human and companion-animal cancers.


Although spaying has shown to lessen the risk of mammary cancer in cats, on the other hand, both spaying and neutering can trigger other types of cancers. Genetic predisposition to cancer plays a role in some breeds, such as Persians, Bengals, and Siamese cats who appear to suffer from cancer at increased rates.

Kinds of cancer that cats develop

In addition to lymphoma, cats most commonly develop mammary cancer and cancers of the skin, soft tissues, bone, pancreas, liver, intestines, respiratory carcinoma, and feline leukemia or mast cell and oral tumors.


Signs and symptoms of feline cancer

While some of the signs of feline cancer may also indicate other non-neoplastic diseases or medical conditions, they need to be considered for a definitive diagnosis. If you observe any of the following in your cat, consult with your veterinarian:

  • Small or large lumps or bumps (mass/tumor) anywhere on the body or face that are visible, or you can feel under the skin.
  • Swelling of the abdomen.
  • Bleeding from any body opening, such as the mouth, nose, ears, rectum, etc.
  • Labored breathing.
  • Difficulty eating.
  • Discolored skin.
  • Wounds that won't heal.
  • Persistent vomiting and/or diarrhea.
  • Sudden changes in weight, such as rapid weight loss or gain.
  • Sudden lameness with no apparent reason.
  • Swelling, heat, or obvious pain in a body part.


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How is cancer diagnosed?

For a definitive diagnosis of cancer, your veterinarian will review your cat's medical history and perform a complete physical examination. Diagnostics include blood work, urinalysis, cytology, imaging (ultrasound,) and biopsy.


Treatment protocol for cancer

Similar to cancer treatment in humans, companion-animal oncology relies on surgery, radiation therapy, chemotherapy, immunotherapy, and photodynamic therapy which all usually have less side effects for animals than human patients.

Prognosis and success rate for feline cancer patients

Some cancers can be cured, and others treated successfully for varying periods. It's vital that your cat's quality of life is the first consideration regardless of the treatment route your veterinarian recommends.

Always check with your veterinarian before changing your pet’s diet, medication, or physical activity routines. This information is not a substitute for a vet’s opinion.