Overall, 131 (39.5%), 25 (7.5%), 7 (2.1%), 167 (50.3%), and 2 (0.6%) patients received no adjuvant treatment, adjuvant chemotherapy, adjuvant RT, adjuvant concurrent chemoradiation ± maintenance chemotherapy, and sequential chemoradiation, respectively. Median RT dose was 50.4Gy (range, 40-59.4Gy). At a median follow-up of 32.2 months (range, 1.6-178.0 months), 3-year LRRFS, DMFS, DFS, and OS were 73.8%, 57.4%, 49.1%, and 64.6%, respectively. In multivariate analysis, adjuvant RT ≥ 50Gy (vs. no RT, HR 0.48, P=0.002), preoperative CA19-9 > 37U/mL (HR 1.79, P=0.013), bile duct resection or hilar resection (vs. pancreaticoduodenectomy or pylorus-preserving pancreaticoduodenectomy, HR 2.25, P=0.021) nodal involvement (HR 1.65, P=0.036), and venous invasion (HR 1.77, P=0.024) were identified as independent prognostic factors for LRRFS. For pT3 stage (81.6% vs 63.7%, P=0.030), node positive (78.9% vs 52.5%, P=0.002), and R1 resected patients (87.5% vs 0.0%, P=0.017), adjuvant RT ≥ 50Gy significantly improved 3-year LRRFS. However, in patients with preoperative CA19-9 > 37U/mL (77.9% vs 59.6%, P=0.100), bile duct resection or hilar resection (68.7% vs 43.9%, P=0.100), venous invasion (67.9% vs 41.2%, P=0.082), the benefit of adjuvant RT was not statistically significant. In node positive patients and R1 resected patients, adjuvant RT ≥ 50Gy significantly improved DFS and OS, respectively. Impact of chemotherapy was not observed over various treatment end-points.