The Cause of Cancer in Dogs and Cats

Veterinary oncologists focus on the treatment of pets diagnosed with various forms of cancer, which is more prevalent in pets than most people realize. Cancer in dogs and cats is common in middle-aged and older pets, accounting for almost half of the deaths in pets over 10 years old. While cancer in pets can be a difficult issue to face, the best veterinary oncologists help to offer acute care and comprehensive treatment plans.

Please be aware that if cancer is detected in your pet, it does not have to mean a death sentence for your beloved pet. Although the news may be devastating, there are many options to consider that can add quality time to your pet’s life. Our oncology department is here to help.

Once your pet receives a diagnosis, you and your family will want to learn as much as possible about the various options available so that you will be able to make an intelligent and informed decision about what is best for your pet and your family. Our specialized veterinary oncology department at Veterinary Specialty Center is here to walk you through those options and answer any questions you may have about your pet’s cancer diagnosis, treatment and prognosis.

Veterinary Specialty Center Oncology

What is cancer?

Cancer is an uncontrolled growth of abnormal cells within the body that can present as a localized tumor, multifocal tumors or systemic disease.

Tumors are divided and classified into two categories: benign or malignant. Benign tumors tend to be slower growing, are not invasive into the surrounding tissue and do not spread (metastasize). Malignant tumors tend to have more rapid growth, may invade into surrounding tissue, and may spread distantly.

Tumors are further classified by the tissue they originate from; carcinomas, sarcomas and round cells.

While surprising to some, cancer in pets is not entirely uncommon, especially among older pets. As your pet ages, it’s important to remain vigilant and bring your pet in for routine check-ups.

Early warning signs of cancer

The following signs are not specific for cancer and may occur with other disease processes as well. If your pet has any of these symptoms, your veterinarian should do a full diagnostic exam to determine what could be causing these symptoms. If something looks unusual or requires further examination, our veterinary oncologists can take a closer look.

  • Abnormal swelling that persists and/or continues to grow
  • Non-healing sores
  • Unexplained weight loss
  • Decreased or loss of appetite
  • Bleeding or abnormal discharge from any body orifice (e.g., mouth, nose, ears, urinary tract or rectum)
  • Recent onset of a persistent offensive odor
  • Difficulty eating or swallowing
  • Decreased or reluctance to exercise
  • Loss of stamina
  • Persistent lameness
  • Increased effort to breath, urinate or defecate

If you see signs of illness or cancer in your pet, contact your veterinarian or our veterinary oncologists as soon as possible.

What to Expect from Your Oncology Visit

Financial Resources for Pet Families Dealing with a Cancer Diagnosis


Starting Monday, April 8th through the end of September, the Illinois Department of Transportation (IDOT) will begin their road resurfacing project along Waukegan Road from Lake Cook Road to Half Day Road (IL 22). Please allow additional travel time to our hospital during the construction. Learn More: Waukegan Road Resurfacing Project