Cancer can be considered a multi-organ, multi-factor, long-latency degenerative and chronic disease that results, in part, from a complex interplay of genetics, diet, lifestyle, inactivity, stress and environmental toxicants. Because carcinogenesis may span up to 10 years or more for certain canine and feline cancers, veterinary researchers have emerging opportunities to seek out dietary chemoprevention strategies to suppress the disease in its early, premalignant stages before clinical, invasive disease develops.