Impact of thoracic radiotherapy on first‐line treatment outcomes in ES‐SCLC patients

Abstract Background The therapeutic advantage of thoracic radiotherapy (tRT) as an adjunct to first‐line immunotherapy and chemotherapy in patients with extensive‐stage small cell lung cancer (ES‐SCLC) remains unclear. We sought to elucidate this in a retrospective cohort study comparing the effectiveness and safety of tRT in combination with first‐line immunotherapy and chemotherapy. Methods Our retrospective study included patients with ES‐SCLC, treated at the West China Hospital between January 2019 and December 2022. They received first‐line immunotherapy and chemotherapy and were categorized into two cohorts based on the administration of tRT. The primary outcomes were overall survival (OS) and progression‐free survival (PFS). Cox regression analysis was utilized to identify potential independent predictors of prognosis and to compare the treatment outcomes across various patient subgroups. Treatment‐related toxicities across both cohorts were compared using the Chi‐squared test. Results A total of 99patients were eligible for the study, out of which 55 received tRT. The medianduration of follow‐up was 39 months. Remarkably, patients who received tRTdemonstrated superior OS and PFS in comparison to those who did not ( P < 0.05). Subgroup analysis further confirmed these findings. Multivariate analysisidentified treatment group and liver metastasis as independent prognosticfactors ( P < 0.05). The incidence of grade 3‐4 adverse events showed nostatistically significant difference between the two cohorts. Conclusions Thus, weconfirmed that the addition of tRT to the conventional regimen of first‐linechemotherapy and immunotherapy yields better survival outcomes without asignificant increase in toxicity.