Cancer Risk Factors: Canine cancer risks increase with size and age, study shows
How big is your dog? Is he or she a purebred or a mixed breed? How old is your dog? The answers to those three questions could help to determine Luna or Leo’s likelihood of getting cancer − and even the type of cancer they may be most prone to.
A biostatistical analysis by Nationwide of claims for more than 1.61 million dogs over a six-year period found that when it comes to a cancer diagnosis, size matters. Large and giant-breed dogs are at higher relative risk for cancer, and it usually occurs earlier in their lives, usually between the ages of 6 and 7.
That pattern holds true for both purebred and mixed-breed dogs, the data show. The retrospective study found a consistent correlation between increased dog size and increased risk of cancer across the populations, but purebred populations had a consistently higher risk than mixed breeds of the same size.
Breeds with the highest relative risk for a cancer claim were boxers, beagles and golden retrievers, while Pomeranians, Chihuahuas and French bulldogs had the lowest. While the risk of a cancer diagnosis rises with age, being a mixed breed, especially one of small size, appears to have a protective effect.
“Everything we see so far suggests that whenever you are crossing out of a gene pool, it would appear that in a highly genetically driven disease process like cancer, that you are diluting the chance that those genes will be mixed together,” says Jules Benson, BVSc, MRCVS, lead author of the white paper and chief veterinary officer at Nationwide.“There’s a genetic element, and there seems to be a size element that is present regardless of genetics.”
How was dog size defined? Toys are 10 pounds or less; small, 11 to 30 pounds; medium, 31 to 50 pounds; large, 51 to 110 pounds; and extra-large, 111 pounds or more.
What does all of this mean for your dog? It provides you with an evidence-based road map to keeping tabs on your dog’s health and catching disease early, when it’s more treatable.
For instance, large and extra-large dogs are at increased risk of bone cancer as early as 6 years old. That’s a good time to start paying closer attention to limping, lumps or bumps in breeds such as Rottweilers, Dobermans and greyhounds −all prone to osteosarcoma.
Boxers are at high risk for skin cancer, with a lower-than-average age of 7.6 years at first cancer claim. Signs of skin cancer in dogs include firm, raised wartlike blemishes; inflamed sores; or odd-colored lumps or bumps on lips, mouth, footpads or toenail beds.
No matter what their breed or mix, more frequent home exams and veterinary exams are important as dogs age. By the time they are between 9 and 10 years old, even toy or small mixed-breed dogs, who have the lowest risk, move into the higher-than-average relative risk category for a cancer claim.
For medium-size, large or extra-large dogs, start thinking about routine diagnostics starting when they are 8 years old. The Nationwide data confirms that lymphoma is a significantly higher risk to middle-aged, midsize dogs than other forms of cancer.
Being familiar with these types of evidence based insights can help you and your veterinarian decide, for instance, when a limp can be managed with rest and pain relievers and when it warrants a closer look with X-rays.
Recognizing signs such as lethargy, decreased appetite, pale gums and a distended abdomen in large or extra-large dogs who are 6 or older can help to catch cancers such as splenic hemangiosarcomas in early stages whentreatment may be able to extend a dog’s survival time or improve quality of life.
Here’s where to read the study yourself: bit.ly/3wI51Dt.
− Kim Campbell Thornton
Do you have a pet question? Send it to askpetconnection@gmail.com or visit Facebook.com/DrMartyBecker. Pet Connection is produced by veterinarian Dr. Marty Becker, journalist Kim Campbell Thornton, and dog trainer/behavior consultant Mikkel Becker.
This article originally appeared on South Bend Tribune: Pet Connection: Know your dog's risk for cancer
