Present states and future prospects of radiation oncology

Present status and future prospect of radiation oncology including advantages obtained by advances of radiation physics, radiation engineering, and radiobiology were described. The so-called adequate methods for cancer treatment should have excellent and absolute cure rate, minimize organic and functional side effects due to irradiation, and make remained lives of patients comfortable after due consideration of extension of tumors, the general state, and aging. Therefore, techniques of radiation therapy must be improved more, and multimodal treatment including other therapies should always be considered. The merit of combined therapies must be evaluated on the basis of their therapeutic ratio. It must be noted that uncertain combined therapies have a possibility to increase damages of normal tissues. (Tsunoda, M.)