[Ewing sarcoma: changes after radiation and chemotherapy]

We retrospectively studied 52 cases of Ewing sarcoma to elucidate the pattern of healing and/or recurrence after radiation and chemotherapy. Persistent soft tissue mass was a sign of failure to respond to therapy. Repair or healing of lytic or blastic bone changes were slow and often minimal, and usually bone changes became gradually stable over 3 years. After bone changes became stable, localized new bone changes represented recurrence or secondary malignant neoplasms.