[Radiotherapy-induced solid tumors: review of the literature and risk assessment]

Although the first radiation-induced solid tumor was reported as early as 1902, the risk of second tumor has been underestimated by radiation oncologists who treated large numbers of patients with either benign or malignant diseases. Since then, numerous epidemiological studies yielded better knowledge of the risks of radiation-induced malignancies. For instance, radiation-induced tumors are the first cause of death 10 years after treatment for Hodgkin's disease. We present here a literature review of the risks of radiation-tumors in various organs, related to the irradiation dose, age, and associated diseases. The most sensitive organs are the thyroid, central nervous system, breast, bone, and lung, especially in smokers. Higher risks are observed with increasing doses, the shape of the dose-response curve depending on the tumor type, when the irradiation is performed in children or young adults and in patients with retinoblastomas. The risk of radiation-induced tumors should lead the radiation oncology committee to reconsider the dose and technique of irradiation and to reduce the use of ionizing radiation in benign diseases.