Meta‑analysis of the efficacy and safety of thoracic radiotherapy for extensive‑stage small cell lung cancer  in the era of immunotherapy

Synergistic antitumor effects of thoracic radiotherapy (TRT) are still debated due to conflicting clinical evidence. The aim of the present meta-analysis was to evaluate the efficacy and safety of chemo-immunotherapy combined with TRT in extensive-stage small cell lung cancer (ES-SCLC). CNKI, Wanfang, VIP, Pubmed, Embase and the Cochrane library were searched for published literature on chemo-immunotherapy combined with TRT for ES-SCLC between January 1, 2018, and March 4, 2024. After screening the studies and extracting data according to the inclusion criteria, Review Manager 5.4 and Stata 15 were used to assess the risk of bias of the studies and perform a meta-analysis of the data. A total of 19 relevant prospective and retrospective clinical research articles were included, involving 1,557 patients. The results of the meta-analysis demonstrated that, in terms of efficacy, chemo-immunotherapy combined with TRT significantly improves overall survival [OS; hazard ratio (HR)=0.49; 95% confidence interval, (CI), 0.34-0.71; P<0.05] and progression-free survival (PFS; HR=0.62; 95% CI, 0.51-0.76; P<0.05) of patients with ES-SCLC. Sub-group analysis indicated that primary liver metastasis was an independent predictor of poor OS (HR=2.45; 95% CI, 1.84-3.25; P<0.05), and TRT was a favorable predictor of OS (HR=0.44; 95% CI, 0.21-0.96; P<0.05) and PFS (HR=0.59; 95% CI, 0.47-0.76; P<0.05). In terms of safety, the incidence of grade ≥3 adverse reactions in the chemo-immunotherapy/TRT combination group was significantly higher than that in the chemo-immunotherapy group (risk ratio=1.30; 95% CI, 1.02-1.66; P<0.05). The most common adverse reactions in the chemo-immunotherapy/TRT combination group were radiation pneumonitis (27%; 95% CI, 14-41%), radiation esophagitis (17%; 95% CI, 9-25%) and thrombocytopenia (9%; 95% CI, 5-14%). In conclusion, chemo-immunotherapy combined with TRT demonstrated improved survival outcomes in patients with ES-SCLC, with acceptable toxicity profiles. However, further validation through prospective clinical trials is warranted.