Background: Immunotherapy combined with chemotherapy has become the standard first-line treatment for extensive-stage small cell lung cancer (ES-SCLC). However, the impact of thoracic radiation therapy (TRT) in these patients remains unknown. The aim of this study was to evaluate the efficacy and safety of TRT in elderly patients with ES-SCLC following first-line chemoimmunotherapy.
Methods: We included elderly ES-SCLC patients (age ≥70 years) treated at three hospitals(Shandong Cancer Hospital, Tianjin Cancer Hospital and Shanghai Chest Hospital) during 2020-2023 who received first-line immunotherapy and chemotherapy and were divided into two groups based on the administration of TRT. The primary outcomes were overall survival (OS) and progression‐free survival (PFS). The Cox regression models were used to analyze independent prognostic factors and to compare the prognosis of each subgroup of patients. Treatment-related toxicity was compared between the two groups using the Chi‐squared test.
Results: A total of 240 patients were eligible for this study, 83 of whom received TRT. The mPFS (10.56 months vs. 8.30 months, P=0.034) and mOS (18.43 months vs. 14.39 months, P=0.008) were significantly different, and the 1-year OS rates of IO+ChT+TRT group and IO+ChT group were 72.29% and 53.50%, respectively, the 2-year OS rates were 15.66% and 9.55%, respectively. The incidence of grade ≥3 adverse events in IO+ChT+TRT group was not significantly different from that of IO+ChT group. The incidence rates of radiation pneumonitis and radiation esophagitis in the IO+ChT+TRT group were 14.89% and 10.64%, respectively. The univariate multifactorial analysis demonstrated that baseline liver metastasis was an unfavorable prognostic factor.
Conclusion: The thoracic radiotherapy can provide a survival benefit without significant toxicity in elderly patients with ES-SCLC treated with first-line immunotherapy combined with chemotherapy. The results of this study have important clinical implications for the future treatment of elderly patients with ES-SCLC.