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Oklahoma State University
Center for Veterinary Health Sciences

Healthy Animals - Healthy People

Cancer and Pets

Wednesday, November 8 2017

golden retriever with vet

Neoplasia is the uncontrolled, abnormal growth of cells in the body. The growth itself is called a neoplasm or tumor.

Tumors can be benign or malignant. Benign neoplasms tend to grow slowly. They displace, but do not invade, surrounding body tissues and do not spread throughout the body.

Malignant neoplasms, on the other hand, can be unpredictable and grow at various rates, sometimes rapidly. They invade surrounding tissues and spread or metastasize to other parts of the body.

The word “cancer” is often confused with neoplasia. Only malignant neoplasms are truly cancers.

According to the American Veterinary Medical Association, approximately one in four dogs will develop neoplasia at some stage in their life. Almost half of dogs over the age of 10 will develop cancer.

Dogs get cancer at roughly the same rate as humans while there is less information about the rate of cancer in cats. Some cancers, such as lymphoma, are more common in cats than in dogs.

Early detection and treatment are key to managing neoplasia in pets. Regular wellness exams establish a baseline for your pet’s health. Any deviations from that baseline may require additional tests such as radiographs, blood tests and ultrasound exams.

Cytology can quickly provide basic information about the tumor type and confirm a diagnosis for certain types of cancer. Cytology is withdrawing some cells from a mass to examine under a microscope.

A biopsy—taking a tissue sample from the neoplasm for microscopic examination—is often necessary to confirm the diagnosis and help determine if it is benign or malignant. If cancerous, additional cytology or biopsies of other tissues, such as lymph nodes may be necessary to determine how far the cancer has spread.

Advanced imaging—computed tomography (CT) scan, magnetic resonance imaging (MRI), or positron emission tomography (PET) scan—can improve the understanding of the tumor’s location and possible treatment options.

Is neoplasia preventable? Unfortunately, the cause of most neoplastic diseases is not known. Therefore, prevention is difficult. Research shows that secondhand smoke increases the risk of some cancers in dogs and cats.

Spaying reduces the risk of mammary cancer in dogs. Fifty percent of breast neoplasms in dogs and more than 85 percent of breast neoplasms in cats are malignant. Spaying female pets before 12 months of age reduces this risk.

Neutering pets eliminates the risk of testicular cancer. However, there is evidence that spaying and neutering can increase the risk of other cancers. Genetic predisposition to some cancers in certain breeds or breeding lines has also been reported.

Talk to your veterinarian about the risks, benefits and timing of spaying or neutering your pet.

Remember that early detection and treatment yield the best results. Consult your veterinarian if you observe any of the following signs in your pet:

  • Abdominal swelling
  • Bleeding from the mouth, nose or other body openings
  • Difficulty breathing
  • Difficulty eating or loss of appetite
  • Lumps, bumps or discolored skin
  • Non-healing wounds
  • Persistent diarrhea or vomiting
  • Sudden changes in weight
  • Unexplained swelling, heat, pain or lameness
  • Visible mass/tumor

by Elisabeth J. Giedt, DVM


Veterinary Viewpoints is provided by the faculty of the OSU Veterinary Medical Hospital.  Certified by the American Animal Hospital Association, the hospital is open to the public providing routine and specialized care for all species and 24-hour emergency care, 365 days a year.