The ESTRO Regaud lecture. Inherent radiosensitivity of tumor and normal tissue cells as a predictor of human tumor response.

This lecture reviews the history and current status of attempts to correlate the outcome of radiation therapy with estimates of tumor cell radiosensitivity, made by either histologic assessment of tumors irradiated in vivo or by assays for the survival of tumor cells irradiated in vitro. Genetically determined variability in the radiosensitivity of normal tissue cells from different individuals is also discussed in terms of its effect on the determination of "tolerance" doses and the possible correlation between tumor cell and normal tissue cell radiosensitivity in a given patient. It is concluded that measurement of both tumor cell and normal tissue cell radiosensitivities, along with other radiobiologically-based assays, will improve our ability to predict treatment outcome and provide the basis for further therapeutic advances in radiation oncology.