Evaluation of the Use of Prophylactic Cranial Irradiation in Small-Cell Lung Cancer

Abstract

<h3>Background</h3> Prophylactic cranial irradiation (PCI) is used in patients with small-cell lung cancer (SCLC) to reduce the incidence of brain metastasis after primary therapy. Our purpose was to evaluate the effects of PCI on overall survival (OS) and cause-specific survival. <h3>Patients and Methods</h3> A total of 7995 patients with limited-stage SCLC diagnosed between 1988 and 1997 were retrospectively identified from centers participating in the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program. Six hundred seventy patients were identified as having received PCI as a component of their first course of therapy. Overall survival and cause-specific survival were estimated by the Kaplan-Meier method, comparing patients treated with or without prophylactic whole-brain radiation therapy. The Cox proportional hazards model was used in the multivariate analysis to evaluate potential prognostic factors. <h3>Results</h3> The median follow-up time was 13 months (range, 1-180 months). Overall survival at 2 years and 5 years was 23% and 11%, respectively, in patients who did not receive PCI. In patients who received PCI, 2-year and 5-year OS was 42% and 19%, respectively (<i>P</i> < 0.001). Cause-specific survival at 2 and 5 years was 28% and 15%, respectively, in patients who did not receive PCI and 45% and 24%, respectively, in patients who did receive PCI (<i>P</i> < 0.001). On multivariate analysis of cause-specific and OS, age at diagnosis, sex, grade, extent of primary disease, size of disease, extent of nodal involvement, and PCI were significant (<i>P</i> < 0.001). The hazard ratios for disease-specific and all-cause mortality were 1.13 and 1.11 for those not receiving PCI, respectively. <h3>Conclusion</h3> Significantly improved overall and cause-specific survival were observed in patients treated with PCI on unadjusted and adjusted analyses. This study concurs with the European experience, which has been published. Prophylactic cranial irradiation should be considered the standard of care in SCLC.