Black Great Dane dog lying on white background

What Do I Need to Know about Cancer and Pets?

Cancer affects us all. We can each name someone we know who has battled cancer, and this is no different for our pets. Cancer is a terrible, pervasive disease.

A Saint Bernard smiling for the camera sitting down.

Both dogs and cats are susceptible to cancer, but it occurs about twice as often in dogs than it does in cats. Diagnosis in cats can be more difficult, though, due to their ability to hide warning signs. This means that cancer in cats is usually detected later than in dogs, when it can be more difficult to treat. There are also certain dog breeds that can be more likely to have an inherited susceptibility to cancer, such as Boxers, Boston Terriers, Golden Retrievers, Great Danes, and Saint Bernards.

November is Pet Cancer Awareness Month, and now is the time for you to become informed about the causes of cancer, the warning signs, and ways you can help prevent cancer in your pets.

So, What Is Cancer and What Causes It?

Cancer is caused when your cells grow uncontrollably, and spread to surrounding areas of your body. Cancer can present as a localized tumor and remain in one area of your body, or it can spread throughout the body. Read more about cancer and join a walk in your area to promote education and cancer research by visiting Puppy Up! Foundation here.

Cancer can have several different causes:

Naturally Occurring Chemicals.

Plants naturally produce chemicals they use to fight off predators, and they can affect you or your pet negatively as well, by causing mutations in DNA.

Man-Made Chemicals.

A bunch of plastic containers containing chemicals and poison in them showing common household toxins.

Pesticides, herbicides, chemical food additives and preservatives, cleaning products, and second-hand smoke are a few examples of man-made chemicals. Read about natural and artificial preservatives in pet food here.

Irradiation (Exposure to the Sun).

A hound dog sunbathing on the beach with sunglasses on.

Skin cancer is a big worry for people, but is not as common in household pets, although white or partially white animals with low pigmentation are at a higher risk.

Inherited Susceptibility.

An abnormal gene can be inherited from a parent, and that may make a pet or person more likely to develop cancer at some point in the future, but will not automatically mean cancer will develop.


There is evidence that some healthy dogs have developed cancer and other health issues as a result of vaccinations, and dogs with cancer should not receive vaccinations as they can negatively affect the immune system. Fibrosarcoma, or soft tissue sarcoma, is a type of cancer associated with injections and vaccinations (also called injection-site sarcoma). Read more about vaccinations and cancer here. If you’re wondering whether to vaccinate, you can read more here.

Cancer Affects Us All

A little white dog and black and white cat being carried by the vet.

  • 4-8 million dogs are touched by cancer each year
  • 1 in 4 dogs and cats will be diagnosed with cancer
  • Cancer is the number one killer of dogs over 2 years old
  • It accounts for 50% of all disease-related pet deaths
  • Cancer is the number one disease killer of children
  • 16,000 companion animals are diagnosed with cancer daily
  • 50% of dogs over the age of 10 will be diagnosed with cancer
  • 46,000 people are diagnosed with cancer daily
  • 46 children are diagnosed with cancer daily
  • One out of 330 people will develop cancer before the age of 20

For What Signs Should I Watch?

A chocolate lab at the vet, laying down looking sick.

Here are ten early warning signs, or the “Ten L’s” of canine cancer of which you need to be aware:

  • Lumps
  • Lesions
  • Lameness
  • Loss of Appetite
  • Lethargy
  • Loss of Weight
  • Loud Odor
  • Loss of Normal Body Functions
  • Loss of Blood or Bloody Discharge
  • Labored Breathing

If you see these signs in your pet without an explanation-especially if you see more than one of the Ten L’s-then you need to get in to see your vet for an examination.

Treatment Options are Available

If your pet does get the dreaded diagnosis, there are treatment options available to him:


This is a good option if the cancer is localized and has not spread to other areas of the body, or if it is not in a dangerous place for surgery to be performed.


This puts toxic chemicals in the body that will kill cancer cells-however it will kill normal cells as well, thus making people and pets very sick as they go through the process.

Radiation Treatment.

This involves a beam of radiation being directed at cancerous cells while avoiding normal cells. This works only when the cancer is localized to one area.


Stimulating the immune system to fight off cancer on its own by attacking cancer cells.

A Combination of Treatments.

Many people choose to combine some of the above treatments depending on their pet’s situation.

No Treatment.

Some pet owners will choose not to treat their pet’s cancer depending on budgetary restrictions and prognosis. In these cases pain relief will be the main goal of treatment, and the pet’s continued quality of life should be considered.
If your pet receives a cancer diagnosis and treatment recommendation from your vet, then I recommend that you seek a second opinion, and see if there is a veterinary oncologist near you. Different veterinarians have different opinions on the best course of treatment, and you owe it to your pet to hear all of the options available! Read more about the importance of multiple veterinary opinions and about Dr. Mitchener, a veterinary oncologist in Memphis, here.

What Can I Do to Prevent Cancer?

The quality of life you provide for your pet can work with, or work against, whatever genes he was dealt! Make sure you do your part to prevent cancer:

  • Use green cleaning products and don’t expose your pet, or yourself, for that matter, to harsh chemicals.
  • Feed your dogs and cats good quality food. READ THE LABEL!!! Cheap grocery store brands contain chemical additives and preservatives and they are harmful to your pet, just like eating only processed foods, chips and ice cream every day would be harmful to you.
  • Some dogs can benefit from sunscreen, especially if they are white, short-haired, and spend a lot of time outdoors.
  • Make sure to neuter/spay you pet at 6 months! This will prevent the possibility of testicular cancer in males, and greatly reduce the instances of breast cancer in females.
  • Do your research about vaccinations and see if you think the pros outweigh the cons. There are vaccines that are approved to last 7 years, instead of going to the vet every single year.

A Yellow lab playing fetch with a big stick and its ears flopping in the wind.

  • Watching your dog’s weight and getting plenty of exercise together will also be helpful. People who have a positive outlook and are able to move around and enjoy their lives have been shown to do much better at holding disease at bay, so why wouldn’t this be true for your dog?

If you do these things, you will at least be one step ahead of the game! Please share your stories about your pets and cancer in the comment section below.

This Post Has 2 Comments

  1. Melissa Baughman

    I was unable to catch the 12 live stream today. I had registered. Can I watch the 5 pm?

Leave a Reply