The latest from the front lines of canine cancer

The ASPCA guesstimates there are 70-80 million dogs in American households, and according to the National Canine Cancer Foundation, one in three of them will be affected by cancer during their lifetimes — a staggering number. 

“We’re seeing it so much more than we did 20 years ago,” says Dr. Juliana Cyman, a radiation oncologist at Portland Veterinary Oncology Center. “Partly because our pets are living longer, and with any species the longer you live the more predisposed you are to develop some forms of cancers. We have so many treatments for diseases that once meant a death sentence for dogs, and we also have better diagnoses.”  

In decades past, MRIs and CT scans simply weren’t available in veterinary medicine, so dog owners were often unable to discover why their dog was having seizures or losing weight. “Now there’s more awareness of cancer by vets and what they should be looking for,” says Cyman. 

Dr. Kim Freeman, a medical oncologist at Veterinary Cancer and Surgery Specialists, says while canine cancer is on the rise, veterinarians are doing a better job of diagnosing it. “The more we diagnose it the better we’re going to get at treating it,” she says.  “In human medicine, a lot of cancer therapies are becoming more personalized and targeted, and that eventually will evolve into what’s happening in veterinary medicine as well.” 

Advances in treatment 

Treatments for canine cancer now include surgery, chemotherapy, and radiation therapy, all modalities that are very similar to those available to people. Cutting-edge immunotherapies are also being developed, along with advances in alternative treatments and nutrition, Cyman says. “But the advances that have been made in surgery and radiation therapy and chemotherapy over the last 20 years are quite stunning.” 

Dr. Freeman’s clinic, which offers surgery, chemotherapy, immunotherapy and hospice care, is participating in a national study of monoclonal antibody therapy for a form of lymphoma. The immunotherapy helps the body create a specific protein that can help the immune system recognize its targets. “That antibody recognizes that target on the cell and it helps the body’s immune system destroy those cells,” says Freeman. “You’re basically priming the body to heal itself, hopefully better than it can with chemotherapy alone, and potentially instead of using chemotherapy.” 

Heather Macfarlane, a dog and cat nutritionist at Balanced By Nature, believes that highly-processed diets contribute to the occurrence of cancer.  “Highly-processed diets lead to chronic inflammation in the body,” she says. “Processed dog food (kibble) is way too high in Omega 6, promoting inflammation and cancer. I believe that a lot of canine diseases are caused by chronic inflammation. Chronic inflammation in the body encourages cancer, and highly-processed pet foods are inflammatory by nature.” 

A pet nutrition professional can help develop a diet for optimal health, both before cancer takes hold and during therapy. Most veterinarians will agree that good nutrition helps with cancer recovery.  

“A tailored diet takes into account everything about a specific animal and his or her specific needs,” says McFarlane. “Depending on what kind of cancer, and anything else going on with the dog, specific proteins, organs, veggies, herbs and perhaps fruit go into the recipe just for that dog. I believe optimal nutrition is paramount when preventing or treating any disease — for people and pets!”  

Damaged genes 

In addition to living longer, some dog breeds are simply more prone to cancer. Breeds such as Retrievers are proportionally more likely to experience cancer. “Typically, dogs that are over 70 pounds are more predisposed to getting bone cancer,” says Cyman.  

Dogs are also exposed to known carcinogens more often than you might think. “We know there are certain chemicals that can increase the risk of cancer,” Cyman says, such as garden products and second-hand smoke. “In most instances, a dog’s life is spent in their home and yard, so cancer can be caused by exposure to what chemicals you’re using.”  

The best preventive measures? Dr. Freeman says it’s keeping pets on a well-balanced diet, making sure they get regular exercise, and avoiding carcinogens. Beyond that, genetics play the biggest role. “Sometimes it’s just bad genes,” she says. “But you do everything you can to lower the risk.” 

Early diagnosis is key 

Cyman says the most common mistake she encounters is when clients spot a soft, squishy, mobile lump on their dog and assume it’s a fatty tumor. “Fatty tumors are by far the most common type of lumps and bumps that dogs get,” she says. “So if you guess fatty tumor you’ll be right way more often than wrong, but a lot of mast cell tumors and soft tissue sarcomas mimic fatty tumors.”  

In the event a soft lump is found, Cyman recommends a biopsy, and measuring and mapping them. “Put it on a picture map so you know that one has been checked before and it’s growing slowly,” she says. “Having that done is really important.” 

Bladder cancer can mimic chronic urinary tract infections. Other symptoms to know include single-sided nasal discharge or bleeding. “Nasal discharge often responds to antibiotics,” says Cyman, “but if it’s single-sided it’s more likely to be unusual and we see that in patients that later develop nasal cancer.”  

Lameness can be a sign of bone cancer, especially in large- and giant-breed dogs. “Dogs are usually running and jumping, so certainly sprains and strains are common,” says Cyman, “but for breeds that are predisposed, getting early diagnosis with radiographs is important. People notice lameness and that’s often how sarcomas start out.”  

Just as with people, it’s important to make a habit of routinely observing your dog’s body and behavior, watching for any unusual changes. “With most dogs, their days are kind of similar, so if all of a sudden you’re noticing that your pet is acting out of sorts that can be a clue that something’s awry,” says Cyman.  


Veterinary Cancer & Surgery Specialists
Dr. Kim Freeman, DVM, DACVIM (Oncology)
10400 SE Main St., Milwaukie

Portland Veterinary Oncology Center
Dr. Juliana Cyman, DVM, DACVR (Radiation Oncology)
13655 SW Jenkins Rd., Beaverton

National Canine Cancer Foundation

Heather Macfarlane, PNC
Balanced By Nature, Nutrition Counseling for Dogs and Cats

Vanessa Salvia’s love for animals began as a  child, when stray kittens just seemed to follow her home. She now lives on a sheep farm outside of Eugene, Oregon, with a llama named Linda, a dog, a cat, two horses, a rabbit, two kids and a patient husband.