Pet health insurance info provides details about cancer in dogs

When my dog Harper, a cavalier King Charles spaniel, was diagnosed last year with squamous cell carcinoma of the tonsils, I was stunned. I had never even heard of tonsillar cancer, but it's one of the many types of cancers that can affect dogs of any breed or mix.

According to the National Cancer Institute, approximately 6 million new cancer diagnoses are made in dogs annually. Some breeds have genetic predispositions to certain cancers. Approximately half of all dogs over the age of 10 will be diagnosed with cancer, and it's estimated that 25% of dogs (1 in 4) will develop cancer at some time in their lives. That's roughly the same rate as humans. Perhaps it's because we so closely share the same environment and lifestyle.

Whatever the reason, the more we know about cancer in dogs, the better we can learn to treat or manage it, as well as identify dogs at greatest risk. Inspired by National Pet Cancer Awareness Month, which takes place during November, Nationwide analyzed pet health insurance policy and claims data from the past six years for approximately 1.5 million dogs: purebreds, mixes and crossbreeds. The results may help to lay a foundation for helping veterinary professionals and pet owners know what to look for in certain breeds.

Among the findings:

¦ In an analysis of the top 10 most popular breeds, boxers (the seventh most popular breed) were 2.6 times more likely to have a claim reporting cancer, while Chihuahuas (the eighth most popular breed) were half as likely to have a claim with a cancer diagnosis.

¦ Some similar or related types of dogs showed wide differences. For instance, of the top 100 purebred dogs covered by Nationwide, English cocker spaniels - the third most numerous spaniel breed covered by the pet health insurance company - had a cancer prevalence at 3.5 times the rate of other dogs. American cockers and English springers, the No. 1 and No. 2 spaniels covered by Nationwide, have prevalence rates that are less than half that of the English cocker.

¦ Mixed breeds (dogs with complex or unknown ancestry) and crossbreeds (two different purebreds intentionally bred to create "designer dogs" such as doodles) were half as likely to have a claim submitted for cancer than the average purebred.

¦ Small- to medium-size dogs are at markedly lower risk across all significant cancers.

¦ Areas of the body where cancers typically occur on all types of pets - dogs, cats, birds, small mammals and reptiles - were skin (for example, melanoma); lymph (lymphoma); spleen (hemangiosarcoma, for instance); bone (such as osteosarcoma); and liver (for example, hepatocellular sarcoma, the most common type of primary liver cancer in dogs).

While data analysts haven't yet fully dug into age at diagnosis for different breeds, knowing that beagles, for instance, are at higher risk for urinary cancer gives veterinarians the tools to counsel owners of that breed to keep an eye out for urinary tract infection symptoms - and not to wait to bring in those dogs. In that breed, what looks like a simple UTI could be the start of something more serious, says Dr. Jules Benson, Nationwide's chief veterinary officer. "It's not necessarily personalized medicine, but it's health coaching and health counseling in a way that we haven't necessarily seen before," he says.

Are cats left out in the cold? Nationwide plans to run their numbers in the future.

"We have a ton of feline data," Dr. Benson says. "We know that certain types of cancer occur in cats more commonly, and finding out some of those warning signs - especially for cats, who are so good at hiding everything - that advice might be even more useful than it is for dogs." ¦