Clinical outcomes of thoracic radiotherapy in combination with chemoimmunotherapy in elderly patients with extensive-stage small cell lung cancer.

[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,  = 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,  = 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,  = 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  > 0.05).Multivariate analysis suggested that a KPS (Karnofsky performance status) score ≥ 80 ( = 0.003) was a good predictor of longer OS, whereas liver metastasis ( = 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.