Efficacy and Safety of Different Treatment Regimens in Patients with Small Cell Lung Cancer Progressing from Limited-Stage to Extensive-Stage Disease

Background Limited-stage small cell lung cancer (LS-SCLC) frequently progresses to extensive-stage disease (ES-SCLC) after standard therapy. However, evidence regarding the efficacy and safety of various treatment regimens for this specific patient population remains limited. Objectives This study aimed to evaluate the efficacy and safety of various treatment regimens among patients who progressed from LS-SCLC to ES-SCLC after standard chemoradiotherapy. Design Survival analyses using propensity score matching (PSM) were conducted in patients with LS-SCLC who progressed to ES-SCLC to assess the efficacy and safety of multiple treatment regimens, especially immunotherapy. Methods This retrospective study included 378 patients with LS-SCLC who progressed to ES-SCLC at Shandong Cancer Hospital from January 2018 to December 2024. After propensity score matching (PSM), patients were divided into immunotherapy and non-immunotherapy groups. Data on treatment regimens and clinical outcomes, including objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS), were collected. Kaplan–Meier analysis estimated PFS and OS, and Cox regression identified factors influencing OS. Results Median overall survival (mOS) and median progression-free survival (mPFS) in the immunotherapy group were longer than those in the non-immunotherapy group (16.4 vs 12.3 months, P < 0.05; 5.3 vs 4.9 months, P < 0.05, respectively). In an exploratory subgroup analysis, platinum-based regimens were associated with longer OS only in patients with a treatment-free interval (TFI) of 3 months or longer (median 19.3 vs 12.5 months; HR = 0.65, 95% CI 0.44–0.95, P < 0.05). Conclusion Our exploratory real-world data suggest that immunotherapy is associated with improved patient outcomes in patients with LS-SCLC who progress to ES-SCLC. Platinum-based regimens may be associated with better prognosis in the subgroup with a TFI of 3 months or longer. Given the exploratory nature, further prospective randomized trials are needed to confirm these observations.