PurposeThe role of prophylactic cranial irradiation (PCI) in treatment of extensive-stage small-cell lung cancer (SCLC) is controversial. The aim of this study was to systematically evaluate the efficacy and safety of using PCI in the treatment of extensive-stage SCLC. In the present study, we examined whether PCI was essential for the optimal treatment of extensive-disease small-cell lung cancer. Material and methodsWe searched the PubMed, Embase, Medline, and China National Knowledge Infrastructure databases to identify articles that assessed the efficacy of PCI in treating extensive-stage small-cell lung cancer patients. ResultsWe identified 8 studies that involved a total of 982 patients who received PCI (PCI group) and a total of 4509 patients who did not receive PCI (control group). The results showed that PCI significantly improved the 1-year overall survival rate (HR=1.50; 95% CI: 1.23–1.82; I2=67%; P<0.0001) and reduced the incidence of brain metastasis (HR=0.46; 95% CI: 0.37–0.58; I2=6%; P<0.00001). ConclusionPCI improves the 1-year overall survival rate and reduces the risk of brain metastasis in patients with extensive-stage SCLC.