Malignant Pleural Effusion at Presentation in Patients with Small-Cell Lung Cancer

BACKGROUND: Malignant pleural effusion (MPE) is commonly seen in patients with non-small cell lung cancer. However, the prevalence of MPE at presentation in small-cell lung cancer (SCLC) is not reported and the clinical impact of MPE at presentation on patients with SCLC remains largely unknown. OBJECTIVE: The objective of this study is to assess the occurrence rate of MPE and its prognostic implications at presentation in patients with SCLC. METHOD: We used the Surveillance Epidemiology and End Results (SEER) registry to extract data from patients with SCLC diagnosed between 2004 and 2014. The Kaplan-Meier method was used to estimate the overall survival and the Cox proportional hazard model was used to evaluate whether MPE was an independent risk for outcome. RESULTS: Among the 68,443 patients with SCLC, MPE was present in 7,639 (11.16%). The probability of MPE was higher in older patients with larger tumors and mediastinal lymph node involvement at presentation. Median overall survival (3 vs. 7 months), estimated 1-year survival (17 vs. 30%), and 2-year survival (6 vs. 14%) were significantly lower in patients with MPE than without MPE, respectively (hazard ratio [HR] 1.46, 95% confidence interval [CI] 1.41-1.50, p< 0.001). MPE was also an independent factor for worse survival in multivariate analysis (HR 1.36, 95% CI 1.32-1.41, p < 0.001). CONCLUSIONS: MPE is common at presentation (11%) in patients with SCLC and may be associated with decreased survival. Additional studies are required to assess the treatment-adjusted survival rate in the setting of MPE.