Concomitant chemotherapy and radiotherapy: theoretical basis and clinical experience.

Combined radiotherapy and chemotherapy can be used in order to improve control and survival rates of solid tumors A concomitant radio-chemotherapy schedule optimizes interactions between chemotherapy and radiotherapy compared to a sequential approach. Experimental data try to explain these interactions at tissular, cellular or molecular levels. Cisplatin, 5 FU, mitomycin C, etoposide and hydroxyurea are particularly efficient to sensitize radiation treatment in order to obtain a supra-additive effect. Therapeutic gain without excess of toxicity should be the aim of clinical trials. This goal may have been achieved for some tumors, specially for oesophageal, rectal, pancreatic and anus cancer. For other tumors (head and neck, lung, bladder, uterine, cervix and gastric cancer) there is strong experimental and clinical support to continue this approach by clinical trials.