Comparative toxicity and efficacy of consolidative thoracic radiotherapy after first-line chemoimmunotherapy in extensive-stage small-cell lung cancer: real-world retrospective cohort study.

Abstract

Background: First-line chemoimmunotherapy (CT-IT) is the standard treatment for extensive-stage small-cell lung cancer (ES-SCLC), while consolidative thoracic radiotherapy (cTRT) may improve local control and survival. This study evaluated the efficacy and safety of cTRT after first-line CT-IT in patients with ES-SCLC in a real-world setting.

Methods: This retrospective cohort study included 199 patients with ES-SCLC who received first-line CT-IT. Patients were divided into a CT-IT + cTRT group (n = 97) and a CT-IT alone group (n = 102). Survival outcomes included progression-free survival (PFS) and overall survival (OS). Treatment-related adverse events were assessed.

Results: The two groups were generally comparable at baseline, although the CT-IT + cTRT group had fewer brain metastases and more favorable response-related features after induction treatment. Median PFS and OS were significantly longer in the CT-IT + cTRT group (both P < 0.001). cTRT (P < 0.001) and a longer duration of maintenance immunotherapy (P = 0.031) were independently associated with a better PFS. For OS, cTRT was associated with better survival status (P = 0.003) and liver metastasis with poorer survival status (P = 0.015). Regarding safety, grade 1-2 dermatitis and gastrointestinal toxicity were more frequent in the CT-IT + cTRT group, whereas rates of pneumonitis, esophagitis, immune-related adverse events, and grade 3-4 toxicities were comparable between groups.

Conclusion: In this real-world retrospective cohort, the addition of cTRT to first-line CT-IT was associated with significantly improved PFS and OS in patients with ES-SCLC, without an apparent increase in severe treatment-related toxicity. Prospective studies are warranted to confirm these findings and refine patient selection for cTRT.