Primary bone cancers (cancers that start in the bones) occur most often in older children and teens, but they can develop at any age. They account for about 4% of childhood cancers.
Primary bone cancer is different from metastatic bone cancer, which is cancer that started somewhere else in the body and has spread to the bone. Metastatic bone cancer is more common than primary bone cancer because many types of cancer (including many cancers in adults) can spread to the bone.
Two main types of primary bone cancers occur in children:
Osteosarcoma is most common in teens, and usually develops in areas where the bone is growing quickly, such as near the ends of the long bones in the legs or arms. It often causes bone pain that gets worse at night or with activity. It can also cause swelling in the area around the bone.
Ewing sarcoma is a less common type of bone cancer, which can also cause bone pain. It is most often found in young teens. The most common places for it to start are the bones in the pelvis, the chest wall (such as the ribs or shoulder blades), or in the middle of the long leg bones.