Can Dogs Get Cancer From Being Overweight?
Obesity is linked to increased rates of cancer in dogs.
Does My Dog Have Cancer Because She Is Obese?
"I have always fed my dog good food and healthy snacks from the table. I know she is kind of chubby, but she is only eight and has cancer. Did my dog get cancer because she is obese?" —Eliza
Obesity in Dogs
Obesity is a big issue among both humans and house pets. About a third of the dogs in the US are overweight and obese. In Japan, a place that does not have the obesity rates seen in humans in the US, obesity rates among dogs are similar. Even in a city like São Paulo in Brazil, 40% of dogs are overweight or obese. (1)
Health Risks of Obesity in Canines
Obesity has several health effects (arthritis, respiratory problems, diabetes, etc.), and one of those is increased rates of cancer. (2)
There still needs to be a lot more research in this area, as we have found that some cancers are also related to bacterial changes in the gut and toxins like processed dog foods, but veterinarians already know that obese dogs are much more likely to develop some types of cancer.
Why Are Obese Dogs at Higher Risk for Cancer?
Overweight dogs have excess fat in the body, and the carcinogenic effects of excess fat have been studied in both people and animals. It has been found that the adipose (fat) tissues produce adipokines that cause cell damage and lead to the secretion of inflammatory cytokines. (3) Because of that, pets with excess fat live in a state of chronic low-grade inflammation.
But is cancer always caused by that low-grade inflammation? Not at all. There are genetic factors involved (some breeds are more prone to get some types of cancer), and there are certain types of cancers that are related to obesity.
Mammary tumors, which occur in about 53% of all unspayed female dogs (4), are related to obesity. Mast cell tumors and transitional cell carcinomas have also been linked to obesity in dogs. Osteosarcomas and lymphomas are not linked with obesity. (5)
Will Keeping Your Dog Underweight Prevent Cancer?
No. Keeping your dog thin is not going to guarantee that they will not develop cancer, but it will definitely make them less likely to develop some types.
How to Keep Your Dog Fit
But how do I keep my dog from becoming obese? Dogs only eat what you feed them, so there is no excuse to have an obese dog. If you notice that your dog is becoming overweight, start feeding them less, exercise them more, and use every opportunity you can to help your dog get in shape.
Keeping your dog from becoming obese is not going to guarantee that they do not develop cancer, but it should be one of the changes you make to keep your dog as healthy as possible.
Sources
(1) Porsani MYH, Teixeira FA, Oliveira VV, Pedrinelli V, Dias RA, German AJ, Brunetto MA. Prevalence of canine obesity in the city of São Paulo, Brazil. Sci Rep. 2020 Aug 21;10(1):14082. https://pubmed.ncbi.nlm.nih.gov/32826948/
(2) Marchi PH, Vendramini THA, Perini MP, Zafalon RVA, Amaral AR, Ochamotto VA, Da Silveira JC, Dagli MLZ, Brunetto MA. Obesity, inflammation, and cancer in dogs: Review and perspectives. Front Vet Sci. 2022 Oct 3;9:1004122. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9573962/
(3) Zoran DL. Obesity in dogs and cats: a metabolic and endocrine disorder. Vet Clin North Am Small Anim Pract. 2010 Mar;40(2):221-39. https://pubmed.ncbi.nlm.nih.gov/20219485/
(4) Moe L. Population-based incidence of mammary tumours in some dog breeds. J Reprod Fertil Suppl. 2001;57:439-43. https://pubmed.ncbi.nlm.nih.gov/11787188/
(5) Romano FR, Heinze CR, Barber LG, Mason JB, Freeman LM. Association between Body Condition Score and Cancer Prognosis in Dogs with Lymphoma and Osteosarcoma. J Vet Intern Med. 2016 Jul;30(4):1179-86. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5153966/
This article is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from your veterinarian. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.
© 2023 Mark dos Anjos, DVM
