Greater survival benefits in small cell lung cancer patients: a real-world study with immune checkpoint inhibitors therapy.

Background: Small-cell lung cancer (SCLC) is a highly aggressive neuroendocrine malignancy. Immune checkpoint inhibitors (ICIs) combined with chemotherapy have become a standard first-line treatment for extensive-stage SCLC; however, their effectiveness across different clinical settings in real-world practice remains incompletely characterized. This study aimed to retrospectively evaluate the clinical effectiveness of ICI-based therapy across subgroups defined by disease stage, surgery, and radiotherapy status. Methods: Patients with histologically or cytologically confirmed SCLC treated at Tianjin Medical University General Hospital between January 2010 and December 2024 were retrospectively included and classified into ICI and non-ICI groups according to treatment exposure. The primary endpoints were overall survival (OS) and progression-free survival (PFS), and the secondary endpoint was the 12-month objective response rate (ORR). Survival outcomes were estimated using the Kaplan-Meier method and compared using the log-rank test. Multivariable Cox proportional hazards regression was performed to adjust for clinically relevant covariates. Results: A total of 142 patients were included, including 76 in the ICI group and 66 in the non-ICI group. ICI therapy was associated with significantly longer OS in patients with limited-stage SCLC (52 vs. 24 months; HR = 0.31, P = 0.011), extensive-stage SCLC (28 vs. 12 months; HR = 0.29, P = 0.007), stage IIIB-C disease (46 vs. 21 months; HR = 0.37, P = 0.038), and stage IV disease (30 vs. 11 months; HR = 0.26, P = 0.007). Significant PFS improvements were observed primarily in patients with stage IV disease (9 vs. 5 months; HR = 0.31, P = 0.002) and extensive-stage disease (10 vs. 5 months; HR = 0.36, P = 0.003). A significantly higher ORR was observed in the ES-SCLC subgroup, while a numerical increase was observed in the stage IV subgroup. Subgroup analyses further suggested more pronounced survival improvements associated with ICI therapy among patients who did not undergo surgery or radiotherapy. Conclusions: ICI-based therapy was associated with improved survival outcomes in patients with SCLC, with the most consistent benefits observed in advanced-stage disease. More apparent treatment-associated benefits were also observed among patients who did not undergo surgery or radiotherapy. These findings provide real-world evidence supporting the use of ICI-based therapy in SCLC, particularly in advanced-stage disease, but should be interpreted cautiously given the retrospective design and subgroup sample sizes.