[Radiotherapy Combined with Immunotherapy and Chemotherapy Improves Prognosis and Demonstrates Synergistic Effects in Extensive-stage Small Cell Lung Cancer].

Background: Extensive-stage small cell lung cancer (ES-SCLC) is a malignant tumor with remarkable proliferative and invasive ability, which has very poor clinical prognosis due to lack of effective treatments. This study aims to evaluate the efficacy and synergistic effects of radiotherapy (RT) combined with immunotherapy (IT) and chemotherapy (CT) in patients with ES-SCLC.

Methods: A retrospective analysis was performed on 145 ES-SCLC patients treated with first-line CT. Kaplan-Meier analysis and Log-rank tests were used to evaluate survival outcomes, while propensity score matching (PSM) was applied to reduce confounding factors.

Results: The median overall survival (mOS) and median progression-free survival (mPFS) for the entire cohort were 15.7 and 6.9 mon, respectively. The IT+CT group had a significantly longer mOS compared to the CT group (17.2 vs 13.5 mon, P=0.047). Similarly, the RT+CT group demonstrated superior mOS (18.5 vs 12.3 mon, P<0.001) and mPFS (7.1 vs 6.2 mon, P=0.006) compared to the CT group. Multivariate analysis identified RT, IT, and Eastern Cooperative Oncology Group performance status (ECOG PS) as independent prognostic factors for mOS (P<0.05), while gender and ECOG PS were independent predictors for mPFS (P<0.05). Following PSM, the RT+CT group continued to exhibit significant advantages in mOS (18.0 vs 12.1 mon, P<0.001) and mPFS (7.1 vs 5.5 mon, P=0.037) compared to the CT group. Notably, the RT+IT+CT group achieved a markedly longer mOS than the IT+CT group (28.5 vs 15.8 mon, P=0.017). Grade 3-4 adverse events occurred in 27.6% of patients, with no grade 5 adverse events reported.

Conclusions: The combination of RT, IT, and CT significantly enhances the prognosis of ES-SCLC patients. RT plays a key role in their synergistic effects and demonstrates good safety, warranting further research and clinical application.