What Is Bone Cancer?

Bone cancer occurs when there are abnormalities in the cells that make up the bones. Abnormal cells can form benign tumors (which are not cancerous), or malignant tumors (which are cancerous). The tumors can be primary, meaning they began directly in the bone, or secondary, meaning they began somewhere else and spread (metastasized) to the bone.

Primary bone cancers are sarcomas (cancerous tissue) that develop in the bones, and include:

Osteosarcoma - the most common form, which starts in the bone itself.
Chondrosarcoma, which starts in the cartilage cells.
Ewing’s family of tumors, which usually start in the bone, but can start in other tissues and organs.

Most bone cancers are secondary cancers that started elsewhere in the body and then spread to the bone. This is called “metastatic” cancer and often happens to people with advanced breast, prostate and lung cancer.

Other “bone” cancers start in the soft tissue inside the bone called the marrow. These include multiple myeloma, certain lymphomas and all leukemias.