Cancer occurs frequently in all breeds of dogs, and some breeds are predisposed to certain types of cancer. Unfortunately, the German Shepherd is one of them.
For example, hemangiosarcoma, a malignant cancer of the circulatory system, is seen more often in German Shepherds than in any other breed. No screening tests are available, and the hereditary component, if any, is not known. Most often, hemangiosarcoma occurs as a tumor on the spleen or heart. As the tumor grows, internal bleeding may occur. Affected dogs may suddenly appear disoriented, collapse, and exhibit signs of hypovolemic shock. They may also be extremely thirsty. Perhaps most noticeable, their gums may be almost white.
If the tumor is on the spleen, the spleen can be removed. Not all tumors of the spleen are malignant, so it's a good idea to have a biopsy done and wait for the results before making a decision. If the tumor is malignant, or if it is on the heart, treatment is usually unrewarding. Unfortunately, most dogs with hemangiosarcoma succumb either to its primary effects (internal bleeding that cannot be stopped) or to cancer spread to other organs.
Osteosarcoma (bone cancer) occurs more frequently in large breeds, including the German Shepherd. It develops most often on a long bone of a leg and can sometimes be seen as a lump. More often, the owner first notices the dog limping; osteosarcoma is very painful. Owners face the terrible decision of amputation that must be made quickly, as time is of the essence to prevent the spread to other parts of the body. Dogs adjust to the loss of a limb fairly easily, but factors such as age, weight, arthritis, and other joint problems factor into how well the dog can cope with only three legs. Unfortunately, even with the best therapy, survival time for dogs with osteosarcoma is usually only a few months.
Mammary gland tumors are among the most common cancers in dogs, occurring mostly in females who were not spayed early in life. Spaying after the age of 2 years doesn't impart the protection from mammary cancer that earlier spaying does. Approximately 50 percent of all mammary tumors are malignant. Therapy may include surgical excision and chemotherapy.
Lymphosarcoma is another of the more common cancers in dogs. This cancer affects the blood and lymph systems; symptoms may include swelling of the lymph nodes, especially in the lower neck area and behind the "knees." Chemotherapy can extend the lives of many affected dogs.
