An overview of cancer in pets

Just like humans, our pets can get cancer. It is a scary and serious diagnosis, but it does not mean your pet’s life is immediately over. WSU’s veterinary oncologists can discuss with you the treatment options available for your pet and answer any questions you may have.

Cancer is caused by the uncontrolled and purposeless growth of cells in the body, and it can arise from any tissue in the body. Oncology is the branch of medicine dedicated to the study of cancer, and the people treating your pet at WSU are oncologists.

Tumor is a general term for cancer, whether it is benign (“good cancer”) or malignant (“bad cancer”).

What is the difference between malignant and benign tumors?

Some forms of cancer can spread to other sites in the body and far from the original site. This happens when cancer cells enter the blood or lymph vessels and are carried to other organs. These cancers are considered malignant.

When a cancer has spread in this fashion, it is said to have metastasized. Some cancers lack the ability to metastasize but may cause significant damage due to growth and invasion into local tissues.

Tumors that do not metastasize and are not invasive are considered benign.

What is the first step after my pet has been diagnosed with cancer?

The first task for the veterinarian is to determine the extent of the tumor, or tumor staging. Staging information is vital to determine your pet’s prognosis and formulate a treatment plan.

Your veterinarian will evaluate your pet by several methods, including blood tests (e.g., blood count, chemistry profile), urinalysis, radiographs (X-rays), tissue aspirate (a sample taken with a fine needle), and biopsy. Tests your veterinarian may have performed might be repeated at WSU due to the changing nature of your pet’s illness.

Other testing procedures may include ultrasound, specialized radiologic studies (e.g., CT scan, dye contrast studies), bone marrow aspirate, lymph node aspirate, endoscopy (direct examination of the stomach, colon, or bronchi with a specialized scope), and immunologic studies.

It is important to note that medicine is not an exact science and despite these staging procedures, it is still possible to fail to recognize small sites of tumor or the presence of tumor in organs that are difficult to study.

Once the tumor staging has been completed, your veterinarian will better be able to discuss treatment options for your pet. The goal of such therapy will also be discussed. Tumors that have metastasized extensively are usually not curable. Therefore, the objective of therapy for these animals is palliation, or to provide relief of the symptoms and suffering caused by cancer without providing a cure. Localized tumors that are not deeply invasive have the best chance to be cured.

How is cancer treated in pets?

There are several types of therapy used to treat cancer in dogs and cats at WSU, including surgery, chemotherapy, radiation therapy, and immunotherapy. For some tumors, treatment will consist of a single type of therapy, while combination therapy may be recommended for other types of cancer or animals with a more advanced stage of disease.

On occasion, due to the rarity of a particular tumor, a precise treatment recommendation may not be known. In an effort to test newer (and hopefully more effective) forms of therapy, you may be asked to enroll your pet in an investigative clinical trial. The purpose of such a trial is to learn more about the specific type of treatment (that may be of value to humans and other pets with cancer) as well as hopefully provide a benefit to your pet. Only pet owners of animals with tumors for which there is no effective treatment or tumors that have not responded to conventional treatment will be offered investigative therapy for their pets.

Should I put my pet through treatments?

Treating animals with cancer is not appropriate for every pet owner. It takes a strong commitment on the part of the owner. Therapy requires frequent trips to the veterinary hospital and can be expensive. Your veterinarian cannot do it alone since treating pets with cancer is truly a team effort and the pet owner is on the team.

For some forms of cancer treatment, once started, treatment is never stopped during the animal’s life, although the frequency of these treatments can be decreased. It is important for you to present your pet for treatment precisely when requested to do so by your veterinarian since the timing of cancer therapy is critical for obtaining an optimal outcome. In addition, medicines to be given to your pet at home should be administered by you exactly as instructed by your oncologist. Any abnormalities or problems you encounter should be reported to your regular veterinarian or oncologist promptly. Always feel free to ask questions and communicate with us.

Keep in mind your veterinarian is as concerned about the quality of your pet’s life as you are. The goal of the therapy is to keep your pet happy and minimize discomfort. Although some animals may experience transient discomfort from therapy, treatment of most pets with cancer can be accomplished without major distress or detraction from your pet’s enjoyment of life.

What should I do if my pet has been diagnosed with cancer?

Our board-certified oncologists can help to accurately diagnose your pet and to develop a treatment plan. Call 509-335-0711 to schedule an appointment or for more information.

This information is not meant to be a substitute for veterinary care. Always follow the instructions provided by your veterinarian. Washington State University assumes no liability for injury to you or your pet incurred by following these descriptions or procedures.