Dr. Phil Zeltzman, DVM, DACVS, CVJDog Checkups & Preventive Care

Kelly Serfas, a Certified Veterinary Technician in Bethlehem, PA, contributed to this article.

Cancer is one of the scariest words a pet lover can hear. Today, pet parents are taking better and better care of pets: Offering better food, providing more consistent vaccination protection, better dental care and so much more. It’s a great time to be a pet, and pets are living to be older. Just like people though, our aging pets have an increased risk of cancer.

What can we do to keep our pets as healthy as possible? Can some cancers be preventable in dogs?

Chemicals you can eliminate to reduce cancer risk in dogs
Did you know that dogs can be affected by second hand cigarette smoke? The same goes for harsh chemicals, including some cleaning products. You can protect your dog by avoiding smoking areas and checking the labels on cleaning products. If the label directs you to use a product in a well ventilated area, use a mask or avoid the area for a few hours, always assume this applies to your dog too. You should keep your pets away until the fumes have dissipated.

Two types of herbicides have been implicated in a link between chemical lawn treatment and cancer:

• Lawn care products containing insect growth regulators can cause lymphoma.
• Phenoxy herbicides can lead to an increased risk of bladder cancer (transitional cell carcinoma), for example in Scottish terriers.

Asbestos and cancer in dogs
Asbestos has been linked to mesothelioma, a type of cancer usually in the chest. Asbestos is found in old insulation material. If your house is old, have it checked for asbestos.

Obesity and cancer in dogs
An overweight dog may have an increased risk of cancers including breast (mammary) and bladder cancer (transitional cell carcinoma). Incidentally, obesity also increases the risk of some benign tumors, such as lipomas (benign fatty tumors).
One study concluded that “calorie restriction is the most potent, broadly acting cancer-prevention regimen in experimental (cancer) models in a variety of animal species, including mammals¹.”

Genetics and cancer in dogs
Certain dog breeds, as wonderful as they are, are well-known for being predisposed to certain kinds of cancer. It’s important that you research your dog’s lineage so that you know what to watch out for. Examples include:
Hemangiosarcoma and lymphoma in golden retrievers
Bladder cancer (transitional cell carcinoma) in Scottish terriers
Histiocytic sarcoma in flat-coated retrievers and Bernese mountain dogs
Mast cell tumors in boxers.

In theory, we could try to eliminate these cancers through genetic selection, i.e., by only using “good bloodlines” to breed. This would clearly be a monumental task that needs to be undertaken by everyone.

Spaying and neutering to reduce cancer risks in dogs
Mammary cancer is almost 100% preventable in dogs who are spayed before their first heat cycle. The risk for mammary cancer increases with each heat cycle a young female dog goes through. Spaying your pet also eradicates the risk of cancer of the ovaries and the uterus. Logically, testicular cancer can also be eliminated in males by castration. The risk of testicular cancer is higher in cryptorchid dogs with a testicle that is “retained” in the belly, so neutering is even more important in those dogs.

In other words, some cancers can be eliminated. The risk of other cancers can be reduced. Yet others cannot, so early detection is the next best thing we can do. Young dogs should have a thorough exam once a year. And ideally, older dogs should have a complete physical twice a year.

A few types of cancer can be suspected based on blood work, so yearly blood work is a wise precaution as well. Some veterinarians offer more extensive screenings, such as belly ultrasound screenings in senior dogs.

With cancer, as with many other diseases, the sooner a diagnosis is made, the higher our chances of treatment success.

If you have any questions or concerns, you should always visit or call your veterinarian — they are your best resource to ensure the health and well-being of your pets.