LBA4002 Background: Standard of care for patients with (borderline) resectable pancreatic adenocarcinoma is resection followed by adjuvant chemotherapy. Previous studies suggest a benefit of neoadjuvant treatment. We conducted a multicenter phase III randomized controlled trial to evaluate the effect of preoperative chemoradiotherapy. Methods: Patients with (borderline) resectable pancreatic cancer, pathologically confirmed, were randomized between immediate surgery (arm A) and preoperative chemoradiotherapy (arm B), both followed by adjuvant chemotherapy. The preoperative chemoradiotherapy consisted of 15 times of 2.4 Gray (Gy) combined with gemcitabine, 1,000 mg/m2 on days 1, 8 and 15, preceded and followed by a cycle of gemcitabine. Primary endpoint was overall survival (OS), secondary endpoints were (R0) resection rate, disease free survival (DFS), distant metastases free interval (DMFI), locoregional recurrence free interval (LRFI) and toxicity. Accrual was completed between April 23, 2013 and July 25, 2017. Results: In total, 246 patients were included in the intention-to-treat analysis (127 patients in arm A and 119 in arm B). Currently, 142 of the 176 needed events for the primary outcome are observed. OS was significantly better in arm B (median 13.5 vs. 17.1 months; HR 0.71; p = 0.047). This was also the case for R0 resection rate (31% vs. 65%, p = < 0.001), DFS (median 7.9 vs. 11.2 months; HR 0.67; p = 0.010), DMFI (median 10.2 vs 17.1 months; HR 0.63; p = 0.012) and LRFI (median 11.8 vs not reached; HR 0.47; p < 0.001). Resection rates were 72% (91/127) in arm A vs. 62% (74/119) in arm B (p = 0.15). No significant difference was observed in grade ≥ 3 adverse events between both groups (p = 0.17). A subgroup analysis of patients who actually underwent a resection was performed which showed a median OS of 16.8 and 29.9 months respectively (p < 0.001). Conclusion: Our preliminary data show that preoperative chemoradiotherapy significantly improves outcome in (borderline) resectable pancreatic cancer compared to immediate surgery. Updated results will be presented at the meeting. Clinical trial information: NTR3709.