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Canine Cancer Risks Increase With Size and Age: Study | lifestyles

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 determine how likely Luna or Leo are to develop cancer, and even the type of cancer they may be more prone to.

A biostatistical analysis by Nationwide of claims from 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 have a higher relative risk of cancer and it usually occurs earlier in their lives, usually between the ages of 6 and 7 years.

That pattern holds true for both purebred and mongrel dogs, the data shows. The retrospective study found a consistent correlation between increasing dog size and increased cancer risk across populations, but purebred populations were at consistently higher risk than mixed breeds of the same size.

The breeds with the highest relative risk of cancer were Boxers, Beagles and Golden Retrievers, while Pomeranians, Chihuahuas and French Bulldogs had the lowest. Although the risk of a cancer diagnosis increases with age, being a mixed race, especially one of small size, appears to have a protective effect.

“Everything we’ve seen so far suggests that every time you cross a gene pool, it would seem that in a highly genetically driven disease process like cancer, you’re diluting the chance of those genes mixing,” says Jules Benson. , BVSc, MRCVS, white paper lead author and Nationwide Veterinary Director. “There is a genetic element and there seems to be a size element that is present regardless of genetics.”

How was the size of the dog defined? Toys weigh 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 this mean for your dog? It provides you with an evidence-based roadmap for managing your dog’s health and detecting disease early, when it is most treatable.

For example, large and extra-large dogs are at increased risk of bone cancer starting at age 6. That’s a good time to start paying more attention to lameness, lumps, or bumps in breeds like Rottweilers, Dobermans, and Greyhounds, all of which are 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 wart-like patches; inflamed sores; or odd-colored lumps or bumps on the lips, mouth, paw pads, or toenails.

No matter what your breed or mix, more frequent home exams and veterinary exams are important as dogs age. By the time they are 9 to 10 years old, even toy dogs or small mongrels, who have the lowest risk, move into the higher-than-average relative risk category for a cancer claim.

For medium, large, or extra-large dogs, start thinking about routine diagnostics starting at age 8. Nationwide data confirms that lymphoma is a significantly higher risk for middle-aged dogs than for other forms of cancer.

Being familiar with this kind of evidence-based information can help you and your veterinarian decide, for example, when a lameness can be managed with rest and pain medication and when it warrants closer observation with x-rays.

Recognizing signs such as lethargy, decreased appetite, pale gums, and a distended abdomen in large or extra-large dogs 6 years of age and older can help detect cancers such as splenic hemangiosarcoma early when treatment can extend a dog’s survival time or Improve Life Quality.

This is where you can read the study for yourself:

How to ensure the care of your pets

Q: We are writing our will and it occurred to us that we should also have directives for the care of our pets if we are incapacitated or dead. What should we include?

A: You are smart to be thinking about that. Disasters come suddenly and unexpectedly. Planning ahead will help ensure your pets get the care they need if you’re not around.

First, choose a primary person and a backup person who are willing to take care of your pets if need be (perhaps you can promise to do the same). They should have your house keys and a folder containing the pet’s medical records, instructions for regular medications, including where they are and how you entice your pet to take them, a copy of your pet’s license, the name and contact information for your veterinarian, pet insurance information if you have it (and you should), and photos and a physical description of your pets.

Make sure your veterinarian is familiar with the plan of care and has the names of the people you have chosen to care for your pets. You can arrange for your veterinarian to manage an account or charge a credit card you have on file with the clinic if it is not available, with the understanding that you or your estate will pay the bills. Carry a card in your wallet stating that you have pets, how many and what kind, and the names and numbers of people to contact to care for them.

In your will, you can’t leave money directly to a pet, but you can put a certain amount in a trust to cover the caretaker’s lifetime expenses. His attorney can help you set this up in a way that is most beneficial to your pet(s). — Dr. Marty Becker and Mikkel Becker

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Active people have

active dogs

— If you like exercise, you are a good candidate to live with a dog. A study published last month in the journal PLOS ONE found that owners’ exercise routines strongly influence the level of exercise their dogs receive. More than 3,200 responses were collected from dog lovers in France, Germany, the United Kingdom, Canada, and the United States. The analysis showed that owners who engaged in any amount of vigorous exercise were more likely to have a dog that engaged in vigorous exercise. Owners who exercised moderately for more than five days a week were more likely to exercise their dogs for 60 to 90, or more than 90, minutes per day.


Pet Connection is produced by a team of pet care experts. Veterinarian Dr. Marty Becker is founder of the organization Fear Free, co-founder of, and author of many best-selling books on pet care. Kim Campbell Thornton is an award-winning journalist and author who has been writing about animals since 1985. Mikkel Becker is a behavior consultant and lead animal trainer for Fear Free Pets. Dr. Becker can be found at or on Twitter at DrMartyBecker. Kim Campbell Thornton is on and on Twitter at kkcthornton. Mikkel Becker is on and on Twitter at MikkelBecker.


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