[Simultaneous radiochemotherapy].

Simultaneous radiochemotherapy (RCT) means the simultaneous application of radiotherapy and chemotherapy. The major objective of this approach is the improvement of local control. On the cellular level, three types of interactions may be distinguished: additivity, synergism, and sensibilization. The main type of interaction seems to be a simple additive effect. The clinical effect of a simultaneous chemotherapy depends mainly on the cytotoxic action of the drug itself and not on radiosensibilization. Therefore, effective chemotherapeutic drugs are to be delivered in cytotoxic dosages in RCT protocols. Compromises in radiotherapy as the main modality should be avoided. Recent clinical data have shown that simultaneous radiochemotherapy may yield high remission rates in a number of tumor entities (e. g. anal cancer, bladder cancer, head and neck cancer). This seems to improve local control as compared to radiotherapy alone. In some tumors (e. g. head and neck, esophagus), survival may be improved also. However, several questions require future detailed clinical trials. These questions include the value of simultaneous radiochemotherapy compared to optimal fractionation schemes, the clear definition of subgroups of patients with benefit by radiochemotherapy and the optimal dose intensity of cytotoxic drugs.