Bone cancer: osteosarcoma

Osteosarcoma is the most common type of cancer that starts in the bones. The cancer cells in these tumors look like early forms of bone cells that normally help make new bone tissue, but the bone tissue in an osteosarcoma is not as strong as that in normal bones. Osteosarcoma tends to occur in teenagers and young adults, but it can also occur in younger children and older adults. Treatment usually involves chemotherapy, surgery and, sometimes, radiation therapy. Doctors select treatment options based on where the osteosarcoma starts, the size of the cancer, the type and grade of the osteosarcoma, and whether the cancer has spread beyond the bone. Osteosarcoma begins when a healthy bone cell develops changes in its DNA. A cell's DNA contains the instructions that tell a cell what to do. The changes tell the cell to start making new bone when it isn't needed