OSTEOSARCOMA

also called osteogenic sarcoma the most common malignant tumour of bone. It is found more often in males than in females, occurs mostly under the age of 30, and affects mainly the large long bones, with a predilection for the knee area. Major symptoms include pain (intermittent at first, later severe and constant), swelling, limitation of joint motion, a high frequency of pathological fractures, and eventually fever and general debilitation. Metastases (seeding of the malignancy in other parts of the body) occur early, and death usually results from the spread of the disease to the lung. The average length of life after diagnosis is 18 months; the five-year survival rate is less than 10 percent. Treatment usually involves amputation of the affected limb. Osteosarcoma that occurs over age 50 is frequently associated with Paget's disease of bone (q.v.).