A related finding was that obese dogs with breast cancer were four times as likely to have more malignant, aggressive tumors than were dogs of normal weight. Also, there is no increase in the number of cases of testicular cancer in early adulthood in dogs as there is in humans. Dogs with inguinal hernias are also at increased risk. Obviously, neutering of dogs prevents the development of this type of cancer. V. Lymphoma Lymphoma is a cancer of the cells of the immune system.
Canine lymphoma is very similar to non-Hodgkin type lymphomas in humans.
Dogs are more likely to get this type of cancer as they get older. Males and females get this cancer at roughly the same rate. Neutering or spaying does not affect the development of this disease although purebreds are slightly more likely than mixed-breed dogs to get lymphoma. There is also an association between lymphoma and exposure to electromagnetic fields. Dogs living in homes with very high outdoor currents nearby were nearly seven times more likely to develop lymphomas than control dogs.