Impact of thoracic radiation therapy after chemotherapy on survival in extensive‐stage small cell lung cancer: A propensity score‐matched analysis

BACKGROUND: The role of thoracic radiation therapy (TRT) after chemotherapy (CHT) in extensive-stage small cell lung cancer (ES-SCLC) has not been well defined. We investigated whether intensity-modulated radiotherapy (IMRT) improves outcomes in ES-SCLC after CHT compared to CHT alone. METHODS: A total of 292 patients who reached a complete response (CR), partial response (PR), or stable disease (SD) after CHT were assigned into groups: CHT + TRT and CHT alone. Propensity score matching was used to balance patient groups (n = 72 each). RESULTS: The five-year overall survival (OS: 12.3% vs. 3.6%; P  6 cycles of CHT (P = 0.042), CR + PR after CHT (P < 0.001), and TRT (P < 0.001) were independently associated with longer OS compared to CHT alone. CONCLUSION: TRT using IMRT is strongly correlated with improved OS and PFS in ES-SCLC patients reaching CR, PR or SD after CHT. A multicenter, randomized phase III clinical trial is needed to confirm these findings.