Adaptive doses of irradiation-an approach to a new therapy concept for bladder cancer?

Radiation adaptive response in terms of induced radioresistance or hyperradiosensitivity, has been studied in HCV29 (human bladder epithelium) and RT4 (human bladder carcinoma) cell lines. After pre-irradiation doses of 0.05 Gy or 0.1 Gy, HCV29 cells showed induced radioresistance, whereas after pre-irradiation doses of 0.05 Gy, 0.1 Gy, 0.2 Gy, and 0.5 Gy, the RT4 cells clearly showed hyperradiosensitivity. On the basis of these results, an approach has been developed that may lead to a concept for a new radiotherapeutic regimen of bladder cancer that includes protection of normal cells, on the one hand, and the potential of tumor cell damage, on the other hand. These findings need to be confirmed in further studies for the benefit of the patients.