Survival benefits for non-small cell lung cancer patients treated with adaptive radiotherapy

•Tumor match and adaptive radiotherapy allows for decreased margins while maintaining loco-regional control.•Tumor match and adaptive radiotherapy significantly reduces the risk of pneumonitis.•After tumor match and adaptive radiotherapy, we observed a significantly improved progression-free and overall survival. Tumor match and adaptive radiotherapy based on on-treatment imaging increases the precision of RT. This allows a reduction of treatment volume and, consequently, of the dose to organs at risk. We investigate the clinical benefits of tumor match and adaptive radiotherapy for a cohort of non-small cell lung cancer patients (NSCLC). In 2013, tumor match and adaptive radiotherapy based on daily cone-beam CT scans was introduced to ensure adaption of the radiotherapy treatment plan for all patients with significant anatomical changes during radiotherapy. Before 2013, the daily cone-beam CT scans were matched on the vertebra and anatomical changes were not evaluated systematically. To estimate the effect of tumor match and adaptive radiotherapy, 439 consecutive NSCLC patients treated with definitive chemo-radiotherapy (50–66 Gy/25–33 fractions, 2010–2018) were investigated retrospectively. They were split in two groups, pre-ART (before tumor match and adaptive radiotherapy, 184 patients), and ART (after tumor match and adaptive radiotherapy, 255 patients) and compared with respect to clinical, treatment-specific and dosimetric variables (χ2 tests, Mann Whitney U tests), progression, survival and radiation pneumonits (CTCAEv3). Progression-free and overall survival as well as radiation pneumonitis were compared with log-rank tests. Hazard ratios were estimated from Cox proportional hazard regression. No significant differences in stage (p = 0.36), histology (p = 0.35), PS (p = 0.12) and GTV volumes (p = 0.24) were observed. Concomitant chemotherapy was administered more frequently in the ART group (78%) compared to preART (64%), p