Bone Cancer Information

What Is Bone Cancer?

Bone cancer is a rare cancer that forms in the cells of bones. As the supporting framework of the body, the bones provide structure and shape to the body, act as braces for muscles to produce movement and protect internal organs.

Most bones are hollow and consist of a hard outer portion (onto which calcium salts are deposited), a spongy inner tissue that contains bone marrow (which makes and stores blood cells) and cartilage at each end of the bone (which acts as a cushion between bones).

Despite its solid appearance, bone is a very active tissue that is constantly in the process of changing and remodeling. The bone itself contains three main types of cells that control this process: osteoblasts (which form new bone), osteocytes (which help maintain bone) and osteoclasts (which break down bone).

Cancer that begins in the bone (known as primary bone cancer) is not the same disease as cancer that starts in another part of the body and spreads (or metastasizes) to the bone (called secondary bone cancer). While it can occur in any of the bones of the body, primary bone cancer most often occurs in the long bones of the arms and legs.

According to bone cancer information from the American Cancer Society, primary bone cancers account for less than 0.2 percent of all cancers, with approximately 2,900 new cases per year in the United States.

Types of Bone Cancer

Primary bone cancers are a specific subtype of a group of cancers known as sarcomas. Sarcomas are cancers that start in bone, muscle, connective tissue, blood vessels or fat, and can be found anywhere in the body. There are several types of primary bone cancers:

• Osteosarcoma, also known as osteogenic sarcoma, is the most common type of bone cancer and typically starts in bone cells in the arms, legs or pelvis. It occurs most frequently in individuals between the ages of 10 and 30, and is more common in males than females.
• Chondrosarcoma forms in cartilage cells and is the second most common form of the disease. This type of bone cancer rarely occurs in people under the age of 20, and the chances of developing it increase with age.
• Ewing tumor, also known as Ewing’s sarcoma, typically starts in the bones, but can also start in other tissues and muscles. It is the third most common form of primary bone cancer. It occurs most frequently in children and teenagers, and is rarely seen in adults over the age of 30.
• Fibrosarcoma and malignant fibrous histiocytoma typically develop in the soft tissue around the bones, such as tendons, ligaments, fat or muscle. These types of bone cancer also tend to occur in older adults, and usually affect the arms, legs or jaw.
• Giant cell tumor of bone can have benign and malignant forms, although the malignant form is less common. It usually occurs in the arm or leg bones of young and middle-aged adults, and rarely spreads to distant parts of the body. However, these cancers may return after surgical removal, and the chance of spreading to distant sites increases with each local recurrence.
• Chordoma affects bones in the spine and the base of the skull. This type of bone cancer occurs most frequently in adults 30 or older, particularly men. It tends to be a slow growing tumor with a low risk of spreading to distant sites, but may return at the original site if not removed completely during surgery, and may eventually spread to the lungs, liver or lymph nodes.

Metastatic Cancer to Bone 

Tumors that start in other parts of the body and spread to the bone (metastasize) are sometimes referred to as secondary bone cancers. However, these cancers are not truly bone cancers, and they still closely resemble the original cancer.

Breast, lung and prostate cancers are common forms of cancer that frequently spread to the bone. When these cancers spread to bone, they are treated with the same therapies used to treat the primary cancer.

Next Topic: Bone Cancer Risk Factors