Consolidative thoracic radiotherapy following first-line chemo-immunotherapy in extensive-stage small-cell lung cancer: A systematic review and meta-analysis.

BACKGROUND: Immune checkpoint inhibitors (ICIs) combined with first-line platinum-etoposide have changed the standard treatment of extensive-stage small-cell lung cancer (ES-SCLC), yet the role of consolidative thoracic radiotherapy (cTRT) in the chemo-immunotherapy era remains unclear. OBJECTIVES: To evaluate the association of cTRT after first-line chemo-immunotherapy with survival outcomes and treatment-related toxicity in ES-SCLC. DESIGN: Systematic review and meta-analysis. DATA SOURCES AND METHODS: We systematically identified studies evaluating cTRT following first-line chemo-immunotherapy in ES-SCLC. Overall survival (OS) and progression-free survival (PFS) were pooled using hazard ratios (HRs), and safety outcomes were pooled using risk differences (RDs), each with 95% confidence intervals (CIs). RESULTS: Seventeen studies (all non-randomized) involving 2,263 patients were included. cTRT was associated with improved OS (HR 0.63, 95% CI 0.56-0.71; p<0.001; I2=0%) and PFS (HR 0.56, 95% CI 0.46-0.68; p<0.00001). Sensitivity analyses restricted to propensity score-adjusted studies and anti-PD-L1-based regimens showed consistent results. cTRT increased any-grade pneumonitis (RD 0.12, 95% CI 0.03-0.21) and esophagitis (RD 0.22, 95% CI 0.04-0.40), without a significant increase in overall grade ≥3 adverse events (RD 0.02, 95% CI -0.05 to 0.09). CONCLUSION: In ES-SCLC treated with first-line chemo-immunotherapy, cTRT was associated with improved survival and increased localized thoracic toxicity, particularly any-grade pneumonitis and esophagitis, without a significant increase in overall grade ≥3 adverse events. Pending prospective randomized validation, these results could support the use of cTRT after the disease control with first-line chemo-immunotherapy.