Pet cancer prevention is not a well-researched topic, especially in comparison to what is known and recommended in the human medicine field. That is not to say that information used in the human medical field cannot be applied in some ways to our pets. Treatments and diagnostic tools are advancing relatively quickly in the veterinary medical field and in many cases, are based on equivalent disease processes, including cancer, in people. Based on limited studies in veterinary medicine, and many more in human medicine, we can suggest the following recommendations for owners to follow and apply to try keep family pets healthy and hopefully cancer free. There are three categories into which we can organize pet cancer prevention:
- Examine your pet every month and familiarize yourself with any lump, bump or odd mark on your pet’s skin, gums, or eyes. This is easy enough to do when you are petting them, and would be equivalent to a monthly self-breast examination for women.
2. Get to know your pet’s normal behavior and habits. Do they usually eat fast or slowly? Are they going to the bathroom normally and with predictable frequency? Are they having trouble eating certain types of food? Is your pet usually social, enjoys being with the family, or is always underfoot? How long a walk does your dog routinely do? How high can your cat usually jump?
3. Notify your veterinarian if you notice changes such as abnormal odors or discharges coming from your pet, if you notice a non-healing wound, or evidence of pain. Other changes to tell your vet about can include weight loss, lethargy or depression, if your cat is hiding, or you notice coughing or respiratory issues in either your cat or dog.
4. Obesity has been shown to be associated with the development of certain cancers in humans. Fat associated hormones called adipokines have altered profiles in people that likely increase cancer risk. A couple of studies of these hormones in veterinary patients have shown that adipokines may also be associated with development of mammary cancer in dogs at a younger age and more aggressive forms of the cancer are seen as well. Another study showed that dogs underweight when diagnosed with bone cancer (OSA) or lymphoma potentially shortened survival. More studies, as always, need to be done, but at least by keeping your pet at a healthy weight, there will be other benefits in addition to possible cancer prevention.
5. Dietary recommendations are controversial and very few if any are supported by rigorous research. One particular study performed in 2005 showed a decrease risk in development of bladder cancer in Scottish Terriers fed vegetables three times a week. Other potential dietary components that may be associated with an increase cancer risk in dogs and cats include alcohol, anti-oxidants, charred meat, and in one study canned food and tuna increased the risk of cats for developing oral squamous cell carcinoma. Garlic and vitamin D may or may not decrease the risk of development of cancer in dogs and cats.
6. Once again, in humans, many studies have documented repeatedly the benefits of exercise for cancer prevention (reduced risk of colon and breast cancer) and exercise has recently been shown to improve survival rates in women being treated for breast cancer. While it is still an unknown in our veterinary cancer patients, it certainly does not hurt the pet nor the owner to get off the couch more often than not!
- Environmental tobacco smoke is a known culprit for many illnesses and cancers in humans and there are studies implicating its effects on our cats and dogs as well. In one study, environmental tobacco smoke was associated with an increased risk for cats to develop gastrointestinal lymphoma. With no health benefits and only increased risk for both humans and pets, the role of eliminating smoking as part of an effort to prevent cancer is a no-brainer.
2. UV light is associated with skin cancer in humans as well as dogs and cats with white, sparse fur in areas that are prone to receiving sun exposure. Cutaneous hemangiosarcoma and squamous cell carcinoma are both potentially solar induced types of cancer. While it is very hard to prevent dogs from enjoying a nice snooze in the sun, limiting the amount of time they spend sunbathing may help.
3. Asbestos is associated with the development of lung cancer and mesothelioma in humans, and there is an older paper in the veterinary literature showing that it may be a cancer promoting agent in dogs as well. Keep your dogs from exposure to asbestos as you would yourself.
4. Lawn product exposure has been associated with (but have not necessarily been proven to be the cause of) cancers in dogs such as mammary tumors, lymphoma, and transitional cell carcinoma (bladder cancer). In a more recent veterinary study (2012) use of specific lawn care products was associated with greater risk of lymphoma. The use of professionally applied pesticides was associated with a 70% higher risk. The use of flea and tick control products did not affect risk. As careful as you can be about how you take care of your own lawn, just be aware of the fact that others may not be as informed or motivated to change how their lawn is treated, especially when walking your dog outside of your yard.
5. Paints and solvents exposure in people who paint for a living showed a 20% increased risk for development of all tumor types and a 40% increased risk for lung cancer. Dogs who live in an area where there is increased exposure to paints and solvents and/or whose owners regularly use paints and solvents are also at increased risk for cancer development.
- Know your breed. It is well known that selective breeding practices in dogs have altered cancer risks among breeds. Different types of lymphoma, for example, tend to occur more commonly in Golden Retrievers and Doberman Pinschers, and Boxer dogs have a high rate of developing lymphoma as well as other cancers. Pugs and Boxers seem to be predisposed to developing low grade mast cell tumors, and Sharpei’s tend to develop higher grade mast cell tumors.
Unfortunately, choosing a mixed breed dog to avoid or decrease cancer risk is not always the answer either, especially if part of the genetic make-up of the dog includes a breed that is at a higher risk of developing cancer (i.e. golden retrievers, Labrador Retrievers, German Shepherds, Boxers, Doberman Pinschers, Rottweilers, etc.).
In the meantime, cancer research in both the human and veterinary fields continue, and by staying well informed and vigilant, we can keep our pets healthy and part of our family, all while enjoying a good quality of life. To learn more about The Cancer Center at CARES, visit: www.vetcares.com and click on Specialties at the top of the page.
Cancer Prevention Checklist
Avoid second-hand tobacco smoke
Monitor your pet’s weight
Become an expert on your pet’s breed(s)
Have regular veterinary checkups
Avoid long-term exposure to sunlight
Avoid exposure to asbestos
Add vegetables to their diet
Examine your pet once a month
Avoid exposure to lawn chemicals
Exercise your pet regularly
Avoid exposure to paints & solvents
Get to know your pet
By: Jennifer Baez, VMD, DACVIM (Oncology & Internal Medicine) and Beth Overley, VMD, DACVIM (Oncology)