[Adjuvant whole-brain irradiation in small-cell bronchial carcinoma]

PURPOSE: To analyse if prophylactic cranial irradiation in small cell lung cancer for improved survival is indicated; if adjuvant irradiation could cure the microscopic disease; if and how late effects could be minimized. PATIENTS AND METHODS: Data from randomized trials and retrospective studies are critically analysed related to the incidence of central nervous system (CNS) metastases in limited disease patients in complete remission with or without prophylactic cranial irradiation. The mechanisms of late effects on CNS of prophylactic cranial irradiation and combined treatment are presented. RESULTS: Prophylactic cranial irradiation could decrease the incidence of CNS metastases but could not improve survival. A subgroup of patients (9 to 14%) most likely to benefit from prophylactic cranial irradiation includes patients who are likely to have an isolated CNS failure. The actual used total dose in the range 30 to 40 Gy could only conditionally decrease the CNS failure. Higher total and/or daily doses and combined treatment are related with potentially devastating neurologic and intellectual disabilities. CONCLUSIONS: No prospective randomized trial has demonstrated a significant survival advantage for patients treated with prophylactic cranial irradiation. Prophylactic cranial irradiation is capable of reducing the incidence of cerebral metastases and delays CNS failure. A subgroup of patients most likely to benefit from prophylactic cranial irradiation (9 to 14%) includes patients who are likely to have an isolated CNS failure, but this had yet to be demonstrated. The toxicity of treatment is difficult to be influenced. Prophylactic cranial irradiation should not be given concurrently with chemotherapy, a larger interval after chemotherapy is indicated. The total dose should be in the range 30 to 36 Gy and the daily fraction size not larger than 2 Gy.