The incidence of second neoplasms following megavoltage radiation for pediatric tumors

From 1953 to 1975, 330 children received megavoltage for benign or malignant tumors. Fourteen subsequently developed second neoplasms. The 30-year cumulative incidence of second neoplasms was 9.6%. The incidence of second malignant neoplasms may be lower following megavoltage radiation than following orthovoltage radiation.