[The histological types and the effects of radiation on tumors]

The effects of radiation on tumors should be divided into radiosensitivity and radioresponsiveness. The local effects of radiation are not always consistent with curability. Though local control is one requirement to attain cure, the primary factor that affects long-term survival is the natural history of the tumor. The effects of irradiation can not be predicted only by determining the histological type of tumor. However, the natural history of the tumor can be understood by careful observation of the stroma in the tumor and condition of the host. As the result, radiocurability can be predicted to some extent.