Clinical impact of first‐line PD‐1 or PD‐L1 inhibitors combined with chemotherapy in extensive‐stage small cell lung cancer patients: A real‐world multicenter propensity score‐matched study

OBJECTIVES: Our research aimed to evaluate the effectiveness of first‐line immune checkpoint inhibitors (ICIs) with etoposide and platinum (EP) for extensive‐stage small cell lung cancer (ES‐SCLC) and identify prognostic factors, as real‐world outcomes and the inconsistency of PD‐1 and PD‐L1 inhibitors are uncertain. METHODS: We selected ES‐SCLC patients in three centers and conducted a propensity score‐matched analysis. The Kaplan–Meier method and Cox proportional hazards regression were conducted to compare the survival outcomes. We also performed univariate and multivariate Cox regression analyses to investigate predictors. RESULTS: Among 236 patients included, 83 pairs of cases were matched. The EP plus ICIs cohort had a longer median overall survival (OS) (17.3 months) than the EP cohort (13.4 months) (hazard ratio [HR], 0.61 [0.45, 0.83]; p = 0.001). The median progression‐free survival (PFS) was also longer in the EP plus ICIs cohort (8.3 months) than in the EP cohort (5.9 months) (HR, 0.44 [0.32, 0.60]; p < 0.001). The EP plus ICIs group had a higher objective response rate (ORR) (EP: 62.3%, EP + ICIs: 84.3%, p < 0.001). Multivariate analysis presented that liver metastases (HR, 2.08; p = 0.018) and lymphocyte–monocyte ratio (LMR) (HR, 0.54; p = 0.049) were independent prognostic factors for OS, and performance status (PS) (HR, 2.11; p = 0.015), liver metastases (HR, 2.64; p = 0.002), and neutrophil‐lymphocyte ratio (NLR) (HR, 0.45; p = 0.028) were for PFS in patients with chemo‐immunotherapy. CONCLUSION: Our real‐world data demonstrated that ICIs with chemotherapy as the first‐line setting for ES‐SCLC are effective and safe. PS, liver metastases, and inflammatory markers could serve as valuable risk factors.