Cancer is common in pet animals such as the dog or cat and the rate increases with age.
Dogs get cancer at roughly the same rate as humans, while cats get fewer cancers.
In one survey, approximately 1 of every 250 dogs and cats developed cancer during their lifetime and cancer accounted for almost half the deaths of those pets over 10 years of age. Since the cause of cancer is not known, prevention is difficult. The exception is breast cancer which is largely preventable with early neutering.