Optimal surgical timing and radiotherapy dose for trimodality therapy in locally advanced non‐small cell lung cancer

PURPOSE/OBJECTIVES: Data are conflicting on the effects of time interval from neoadjuvant chemoradiation (NCRT) to surgery for locally advanced non‐small‐cell lung cancer (LA‐NSCLC). This study investigated the impact of surgical timing after NCRT and radiation dose on postoperative mortality and overall survival (OS). MATERIALS AND METHODS: Using the National Cancer Database, we identified 3489 LA‐NSCLC patients treated with NCRT and surgery. Multivariate Cox proportional hazards analysis (MVA) was used to examine the effects of surgery >7 weeks from NCRT completion on OS. Propensity score (PS)‐matched survival analysis for surgery ≤7 and >7 weeks was performed. Postoperative mortality was assessed. RESULTS: Median OS for surgery ≤7 weeks and >7 weeks after NCRT were 56.9 versus 45.6 months (hazard ratio, HR 1.18 [1.07–1.30]; p < 0.001). Surgery >7 weeks correlated with decreased OS on MVA (HR 1.15 [1.04–1.27]; p = 0.009) and PS matching (HR 1.16 [1.049–1.29]; p = 0.004). Time as a continuous variable correlated with OS on MVA (HR 1.003 [1.001–1.006]; p = 0.0056) and PS matching (HR 1.004 [1.001–1.006]; p = 0.004). Among 2902 lobectomy patients, the mortality rate for surgery ≤66 days was 5.2% versus 8.1% for >66 days (MVA HR 1.59 [1.02–2.49]; p = 0.04). Higher neoadjuvant radiotherapy dose correlated with surgery >7 weeks and lobectomy >66 days on MVA. CONCLUSIONS: Increased interval >7 weeks from NCRT to surgery for LA‐NSCLC is correlated with worse OS and lobectomy ≤66 days correlated with improved OS. Surgery ≤7weeks may improve tumor control, whereas higher mortality for surgery >66 days may relate to late NCRT manifestations. Neoadjuvant doses of 44–50.4 Gy may minimize risks of radiation‐induced lung injury and surgical complications and facilitate surgery within the optimal 7‐week interval.