Overview

Bone cancer begins when cells in the bone begin to change, grow without control, and no longer die, forming a mass called a tumor. Bone cancer is rare and accounts for less than 1% of all new cancers. This section contains information about primary bone cancer (cancer that begins in the bone). It is much more common for bones to be the site of metastasis (spreading) from other cancers, such as breast, lung, or prostate cancer. For information about cancer that has started in another part of the body and spread to the bone, please see the information for that type of cancer.

The human skeletal system is made up of more than 200 bones that protect the internal organs, allow people to stand upright, and attach to muscles that allow movement. Bones are connected to other bones by ligaments, which are bands of tough, fibrous tissue. Cartilage is the tough, fibrous material that covers and protects the joints where bones come together. Bones are hollow and filled with bone marrow, which is spongy, red tissue that produces blood cells.

Bone is a tissue that consists of collagen (a soft, fibrous tissue) and calcium phosphate (a mineral that helps harden and strengthen the bone). There are three types of bone cells:

• Osteoclasts break down and remove old bone.
  
  
• Osteoblasts build new bone.
  
  
• Osteocytes carry nutrients to the bone.

Cancer can occur in any of these parts of the bone. A bone tumor can be benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). Even though a benign tumor does not spread outside the bone, it can grow large enough to press on surrounding tissues and weaken the bone. A malignant tumor can destroy the cortex (the hard outer portion of the bone) and spread to nearby tissue. If bone tumor cells get into the bloodstream, they can spread to other parts of the body, especially the lungs.

There are different types of bone cancer. Osteosarcoma and Ewing’s sarcomaare two of the most common types of bone cancer and generally occur in children and young adults. Chondrosarcoma is cancer of the cartilage and is more common in adults. Chordoma is a type of bone cancer that typically starts in the lower spinal cord. Rare, soft-tissue sarcomas that begin in the bone include malignant fibrous histiocytoma (MFH) and fibrosarcoma. MFH makes up less than 1% of primary bone tumors. It is usually found in adults. The arms and legs, especially around the knee joint, are the most common sites for MFH to appear. Fibrosarcoma is also more common among adults, particularly during middle age, and most often begins in the thighbone. Paget’s disease of the bone generally occurs in older adults and involves the overgrowth of bony tissue.

Statistics

In 2009, an estimated 2,570 adults (1,430 men and 1,140 women) in the United States will be diagnosed with bone cancer. It is estimated that 1,470 deaths (800 men and 670 women) from this disease will occur this year. Primary bone cancer accounts for less than 0.2% of all cancers.

Osteosarcoma and chondrosarcoma each make up 35% of primary bone cancers, followed by Ewing’s family of tumors (10%), chordoma (5%), and MFH/fibrosarcoma (2%). The remaining cases represent other, rare types of bone cancer.

Cancer survival statistics should be interpreted with caution. These estimates are based on data from thousands of cases of this type of cancer, but the actual risk for a particular individual may differ. It is not possible to tell a person how long he or she will live with bone cancer. Because the survival statistics are measured in five-year intervals, they may not represent advances made in the treatment or diagnosis of this cancer.

Statistics adapted from the American Cancer Society's publication, Cancer Facts and Figures 2009.

Find out more about basic cancer terms used in this section.