Unless you're into astrology, the very word “cancer” sends shivers up your spine. A dictionary definition of cancer is “a malignant tumor or neoplasm” — “neo” for new, “plasm” for tissue. With many of the infectious diseases that previously shortened the lives of our dogs under control, with better parasite management and better nutrition, many of our dogs are living longer and healthier lives than ever before. Longer life spans, however, come with an increase in cancer. Cancer is the leading cause of death in dogs over ten years of age.