Cancer, bone: A malignancy in bone. Primary bone cancer, one that begins in bone, is uncommon but it is not unusual for a malignancy to spread to bone from other parts of the body such as from breast, lung, and prostate.

The most common type of primary bone cancer is osteosarcoma, which develops in new tissue in growing bones. Another type of cancer, chondrosarcoma, arises in cartilage. Ewing's sarcoma, still another form of bone cancer, begins in immature nerve tissue in bone marrow. Osteosarcoma and Ewing's sarcoma tend to occur in children and adolescents, while chondrosarcoma occurs more often in adults.

Cancers that metastasize to bone from another location are generally not called bone cancer but are named for the organ or tissue in which the cancer begins as, for example, lung cancer metastatic to bone.

Pain is the most frequent symptom of primary and metastatic cancer in bone. Tumors that occur in or near joints may cause swelling or tenderness in the affected area. Bone cancer can also interfere with normal movements and can weaken the bones, leading to a fracture.

The diagnosis of bone cancer is supported by findings from the medical history and physical examination, blood tests (including the enzyme alkaline phosphatase) and x-ray studies. Diagnosis is confirmed by a biopsy of the tumor.

Treatment depends on the type, location, size, and extent of the tumor. Surgery is often the primary treatment. Although amputation of a limb is sometimes necessary for primary bone cancer, chemotherapy has made limb-sparing surgery possible in many cases. Radiation may also be used.

See: Cancer of the bone.