Cancer of the bone occurs when cells in the bone undergo changes that make the cell grow and divide uncontrollably. This is called primary bone cancer. Cancer can also affect the bone when a cancer spreads from another part of the body to the bones. This is called bone metastasis. Many types of cancer can spread to the bone.

When a cancer spreads from one place to the bone, it is not considered cancer of the bone. The bone metastasis is the same type of cancer as the original tumor, such as lung cancer. The bone metastasis is called by the original tumor name.

What is going on in the body?

The bones support the body and make it possible to move about. Cancers affecting the bone will weaken the bone, and the affected area may break easily. The break can occur for no apparent reason. Or, it may be caused by mild trauma that would not normally be expected to cause a bone to break.

The most common bone cancer is osteosarcoma. It can spread from the bone to other parts of the body if untreated. Osteosarcoma is a rare cancer. It occurs most often in children but can occur in adults.

Any kind of cancer can spread to the bone. This bone metastasis usually occurs late in the disease. Breast, prostate, and lung cancer are the most common types of cancers that spread to the bone. The bones of the spine, pelvis, and ribs are the most commonly affected. The bones of the upper arm and upper leg also may be affected. Multiple myeloma, a type of blood cancer, can affect the bones early in the disease.

What are the causes and risks of the disease?

Osteosarcoma and other bone tumors are rare. A person who has been exposed to radiation may be more at risk for primary bone cancer. A person who has uncontrolled cancer of the breast, lung, or prostate is at high risk for developing bone metastases.