The effect of combined treatment of HeLa cells with cisplatin and irradiation upon survival and recovery from radiation damage.

Combined treatment of HeLa cells with cisplatin and irradiation under aerobic conditions leads to no interaction between the two treatment modalities, either when they are given simultaneously or when cisplatin treatment is followed by irradiation. Simultaneous treatment with cisplatin and irradiation under hypoxic conditions leads to radiosensitization of HeLa cells by cisplatin. This sensitization was independent from the surviving fraction with cisplatin only, the dose modifying factor being approximately 1.2. Pretreatment or post-treatment with cisplatin does not influence the recovery from sublethal radiation damage.