Just as in humans, a dog's tumor can be either malignant or benign. The first step should be to determine which it is. Benign tumors are those that don't spread to surrounding tissues. These can generally be surgically removed without further problems. Malignant tumors are cancerous, and can quickly spread to surrounding areas. If detected early enough, surgical removal, followed by chemotherapy or radiation treatment, can save the dog's life. In some cases, depending on the location of the tumor, amputation of the limb may be necessary. Examine your pet frequently and check with the vet if you detect any unusual lumps, bumps, or swellings. Early detection gives you the best chance of saving your pet's life.