Objective: To determine the role of prophylactic cranial irradiation (PCI) in patients with small cell lung cancer (SCLC). Methods: We searched various databases, selecting randomized clinical trials published in journals or conference proceedings within the last 30 years and investigating the role of PCI in the mortality of patients with SCLC, submitted to PCI or not. Results: Sixteen randomized clinical trials, collectively involving 1,983 patients, were considered eligible for inclusion. Of those 1,983 patients, 1,021 were submitted to PCI and 962 were not. Overall mortality was 4.4% lower in the patients submitted to PCI than in those who were not (OR = 0.73; 95% CI: 0.57-0.97; p = 0.01), especially among the patients showing a complete response after induction chemotherapy (OR = 0.68; 95% CI: 0.50-0.93; p = 0.02) and in those submitted to PCI after that treatment (OR = 0.68; 95% CI: 0.49-0.94; p = 0.03). That decrease did not correlate with the stage of the disease: limited disease (OR = 0.73; 95% CI: 0.55-0.97; p = 0.03); and extensive disease (OR = 0.48; 95% CI: 0.26-0.87; p = 0.02). Conclusions: Our findings suggest that PCI decreases mortality in patients with SCLC, especially in those showing a complete response after induction chemotherapy and in those submitted to PCI after that treatment, regardless of the stage of the disease.

Keywords: Small cell lung carcinoma; Radiotherapy; Survival analysis.