Clinical Outcomes of Thoracic Radiotherapy in Combination with Chemoimmunotherapy in Elderly Patients with Extensive‐stage Small Cell Lung Cancer

Abstract Purpose We evaluated the effect of thoracic radiotherapy (TRT) on extensive‐stage small‐cell lung cancer (ES‐SCLC) in elderly patients (aged ≥ 60 years) in the era of immunotherapy (IO) and analyzed the prognostic factors to guide personalized treatment. Methods The clinical data of 178 elderly patients were reviewed. Kaplan‐Meier curves were generated to estimate the survival rates. Multivariate prognostic analyses were performed using Cox proportional hazards models. Results The mOS in the CRT‐IO group was superior to that in the CT‐IO group (22.0 vs. 14.7 months, P = 0.014). In addition, the mPFS in the CRT‐IO group was significantly longer than that in the CT‐IO group (11.2 vs. 7.0 months, P = 0.023). The mOS in the CRT‐IO group was better than that in the CRT group; however, the difference was not statistically significant (22.0 vs. 17.3 months, P = 0.103). Overall survival was the longest in the CRT‐IO group, followed by the CRT and CT‐IO groups.Patients in the low‐dose group had longer survival times than those in the high‐dose group; however, this difference was not statistically significant (all P > 0.05).Multivariate analysis suggested that a KPS (Karnofsky performance status) score ≥ 80 ( P = 0.003) was a good predictor of longer OS, whereas liver metastasis ( P = 0.004) was associated with shorter OS. Conclusions CRT‐IO should be prioritized as a treatment for elderly patients with ES‐SCLC with good performance status and liver metastasis. However, CRT could be a viable option for patients with a compromised performance status or for whom economic factors are a concern.