PROPHYLACTIC CRANIAL IRRADIATION IN SMALL-CELL LUNG-CANCER - IS IT EVER INDICATED

Prophylactic cranial irradiation (PCI) is being reintroduced into mult imodality treatment protocols of patients with small-cell lung cancer (SCLC). The history of its use brings interesting insights into clinic al evaluations of treatment strategies and design of relevant and info rmative trials. The critical issues of effectiveness and overall healt h gains of prophylactic cranial irradiation have been addressed in a s eries of recently completed clinical trials. These trials tested proph ylactic cranial irradiation in small-cell lung cancer patients achievi ng good response to induction therapy and confirmed the ability of sta ndard prophylactic cranial irradiation schedules to significantly redu ce the lifetime risk of brain metastases. A subset of these trials eva luated neurotoxicity in a formal and prospective manner. No sustained or significant detriment in neuropsychometric function could be linked to the use of prophylactic cranial irradiation. In addition, all the large trials have shown a consistent survival advantage in favor of th e prophylactic cranial irradiation arm. None of the individual sample sizes were large enough to statistically confirm this survival benefit , but a meta-analysis is in progress and will report on this aspect of evidence shortly. Issues that remain to be answered are the optimal d ose and schedule of prophylactic cranial irradiation as well as the ti ming of this administration. These questions form the nucleus of the n ext generation of collaborative trials that are being designed.