Enhanced radioinduced cytotoxicity of cultured human bladder cancer cells using 43 degrees C hyperthermia or anticancer drugs.

Using a colony-forming technique and 2 human bladder cancer cell lines, T24 and KK-47, the enhanced radioinduced cytotoxicity in combination with 43 degrees C hyperthermia (HPT) or 4 anticancer drugs; bleomycin (BLM), cis-dichlorodiammineplatinum (II) (CDDP), mitomycin C (MMC), carbazilquinone (CQ), has been studied. In the series of both cell lines, the combination of 43 degrees C hyperthermia and irradiation resulted in exceedingly enhanced cytotoxicity. This was characterized by a marked decline of the slope of the radiation dose-survival curve as compared with slope in the combination of each of the anticancer drugs and irradiation. Among the 4 anticancer drugs, BLM was thought to be the most promising agent as a potentiator of the radiotherapy, on the basis of a remarkable decrease in the shoulder portion of the radiation dose-survival curve. The other 3 anticancer drugs showed a certain degree of potentiation of radiosensitivity.