Although bone cancer does not have a clearly defined cause, researchers have identified several factors that increase the likelihood of developing these tumors. Osteosarcoma occurs more frequently in people who have had high-dose external radiation therapy or treatment with certain anticancer drugs; children seem to be particularly susceptible. A small number of bone cancers are due to heredity. For example, children who have had hereditary retinoblastoma (an uncommon cancer of the eye) are at a higher risk of developing osteosarcoma, particularly if they are treated with radiation.
Additionally, people who have hereditary defects of bones and people with metal implants, which doctors sometimes use to repair fractures, are more likely to develop osteosarcoma. Ewing sarcoma is not strongly associated with any heredity cancer syndromes, congenital childhood diseases, or previous radiation exposure.