7503 Background: For stage III/N2 NSCLC neoadjuvant chemotherapy (NCT) followed by radical surgery is one standard treatment approach. In our previous trial, this strategy led to a median survival of 33 months (Betticher et al. JCO 2003). We now investigated whether the addition of preoperative radiotherapy (RT) would improve outcome. We report the results of a planned interim analysis on data of the first 219 patients (pts). The trial was closed to accrual in December 2012 due to futility after enrollment of 232 of 240 planned pts. Methods: Pts with pathologically proven, resectable stage IIIA/N2 NSCLC, performance status 0-1, adequate heart, kidney, liver and bone marrow function were randomized 1:1 to receive 3 cycles of NCT (cisplatin 100 mg/m2 and docetaxel 85 mg/m2 d1, q3weeks) followed by accelerated concomitant boost RT (44 Gy/22 fractions in 3 weeks) or NCT alone, with subsequent surgery for all pts. The primary endpoint was event-free survival (EFS). Results: 23 centers included 219 pts. Median ...