There are several different types of bone cancer. Most primary bone cancers are in the category of tumors called sarcomas, a kind of cancer that can affect soft tissues such as muscles and nerves as well as bone. Sarcomas have a diverse range of features at the molecular and cellular level. Because of that, not all bone sarcomas respond to the same types of treatment.
Osteosarcoma is the most common type of primary bone cancer, making up about one third of cases. This cancer mainly affects children and young adults between the ages of 10 and 25. Osteosarcoma often starts at the ends of bones, where new tissue forms as children grow, especially in the knees.
Chondrosarcoma is one of the most common types of primary bone cancer in people over age 50. It forms in cartilage, usually around the pelvis, knees, shoulders, or upper part of the thighs. This cancer makes up about a quarter of all primary bone cancer cases.
Ewing sarcoma usually occurs in the middle part of a bone, most often in the hips, ribs, upper arms, and thighs. Like osteosarcoma, this cancer affects mainly children and young adults between the ages of ten and 25. Ewing sarcoma is responsible for about 15 percent of primary bone cancer cases.
The following bone cancers are rare and occur primarily in adults:
- Fibrosarcoma usually appears in the knees or hips. It can arise in older patients after radiation therapy for other cancers.
- Giant cell tumors, which usually begin in the knees, affect young adults most frequently and women more often than men.
- Adamantinoma usually occurs in the shin bone.
- Chordoma is found most often in the sacrum, which is the lower part of the spine, also known as the tailbone.