Pet Health: Cancer is common in pets; learn the signs during Pet Cancer Awareness Month

Note to Reporters: The following Pet Health column may be reproduced in media outlets with credit to the author, Dr. Rodney Page. Photos accompanying the column are available online at www.news.colostate.edu.

Did you know that cancer is the leading cause of death among dogs more than 2 years old?

This is a startling statistic and might be unknown to people who haven’t confronted cancer in a pet. May is designated as Pet Cancer Awareness Month by the American Veterinary Medical Association, and it’s a good time to bone up on the risks and signs of cancer in pets – and to understand current treatment options.

The Colorado State University Flint Animal Cancer Center is the world’s largest center focused on veterinary oncology, with about 100 scientists and clinicians who handle about 6,000 appointments and 3,000 consultations annually. We also train veterinary students and conduct clinical trials to treat dogs with naturally occurring tumors, while also gaining critical insight in our quest for a cancer cure.

The mission of our Animal Cancer Center is to successfully treat pets with cancer – and to use the knowledge we attain to advance cancer treatment for people. If that sounds far-fetched, it’s useful to know that tumors and their growth are remarkably similar between pets and people; that makes cancer treatment in dogs an ideal model for advancing cancer treatment for human patients.

Here are a couple things we know about cancer in dogs: About half of dogs over the age of 10 will develop cancer; in some breeds, the mortality rate is 50 percent or greater. By comparison, 41 percent of men and women will be diagnosed with cancer during their lifetimes, according to the latest data from the National Cancer Institute.

The prevalence of pet cancers is distressing for those of us who consider our dogs as family members. Yet there’s also good news: About 50 percent of cancers in dogs are curable with surgery, chemotherapy or radiation.

Another 25 percent of canine cancers are controllable, meaning treatment will help to extend life and improve quality of life.

In the final 25 percent of canine cancer patients, it is unreasonable to consider prolonging survival because of the advanced nature of the cancer. In these cases, veterinarians have many tools to provide palliative care, meaning we seek to relieve pain and provide other supportive therapies so the patient is comfortable until the end of life.

As is the case in people, there are different types of cancer in dogs.

Among U.S. men, prostate, lung and colorectal cancers are most common; in U.S. women, breast, lung and colorectal cancers develop most frequently, data from the National Cancer Institute show.

In dogs, we most often see tumors of the lymph nodes; hemangiosarcomas, or tumors that develop in the blood vessels; and osteosarcomas, or bone cancers; and sarcomas in general.

Early detection and treatment are important for dogs, just as for people. So it’s helpful to know the top 10 warning signs of cancer in pets:

• Abnormal swellings that persist or grow
As we like to suggest, pet your pet! This is the best way to find lumps, bumps or swelling that could be anywhere on the body.
• Sores that don’t heal
Non-healing sores can be a sign of infection or cancer. Your veterinarian can determine the reason a sore is not healing.
• Weight loss
Illness could be to blame if your pet is losing weight but is not on a diet.
• Loss of appetite
It’s not normal for pets to lose their appetite; inappetence is another sign of possible illness.
• Bleeding or discharge from any body opening
Bleeding can occur for a number of reasons, most of which are abnormal. We consider unexplained vomiting and diarrhea as abnormal discharges, as well.
• Offensive odor
This is a common sign, especially for tumors of the anus, mouth or nose.
• Difficulty eating or swallowing
This is a common sign of cancers of the mouth or neck.
• Hesitation to exercise or loss of stamina
This can be one of the first signs that your pet is not feeling well.
• Persistent lameness
There can be many causes of lameness, including nerve, muscle or bone cancer.
• Difficulty breathing, urinating or defecating
Schedule a veterinary evaluation if your pet displays any of these symptoms.

Your pet should be seen by a veterinarian if any of these signs arise, as these symptoms may point to a variety of illnesses and diseases, including cancer. Early diagnosis often means better treatment options. We recommend checkups so your pet’s health is monitored regularly.

The CSU Flint Animal Cancer Center also has a number of ongoing clinical trials. These studies help doctors in the medical and veterinary fields investigate methods to improve detection and treatment of cancer, as well as improve the quality of care each patient receives. To learn about options, visit csuanimalcancercenter.org/clinical-trials.

Dr. Rodney Page is a veterinary oncologist and director of Colorado State University’s Flint Animal Cancer Center.

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