LAUSR

OBJECTIVE To investigate the oncological outcomes of patients with pancreatic ductal adenocarcinoma (PDAC) who had a R0 or R1 resection based on the revised R status (1 mm) after neoadjuvant therapy (NAT). BACKGROUND The revised R status is an independent prognostic factor in upfront-resected PDAC; however, the significance of 1 mm margin clearance after NAT remains controversial. METHODS Patients undergoing pancreatectomy following NAT for PDAC were identified from two prospectively maintained databases. Clinicopathological and survival data were analyzed. The primary outcomes were overall survival (OS), recurrence-free survival (RFS), and pattern of recurrence in association with R0>1 mm and R1≤1 mm resections. RESULTS Three hundred fifty-seven patients with PDAC were included after NAT and subsequent pancreatic resection. Two hundred eight patients (58.3%) received FOLFIRINOX, 41 patients (11.5%) gemcitabine-based regimens, and 299 individuals (83.8%) received additional radiotherapy. R0 resections were achieved in 272 patients (76.2%) and 85 patients (23.8%) had R1 resections. Median OS after R0 was 41.0 months, compared with 20.6 months after R1 resection (P=0.002) and even longer after additional adjuvant chemotherapy (R0 44.8 mo vs. R1 23.3 mo; P=0.0032). Median RFS in the R0 subgroup was 17.5 months versus 9.4 months in the R1 subgroup (P<0.0001). R status was confirmed as an independent predictor for OS (R1: HR 1.56, 95% CI 1.07-2.26) and RFS (R1: HR 1.52; 95% CI 1.14-2.0). In addition, R1 resections were significantly associated with local but not distant recurrence (P=0.0005). CONCLUSION The revised R status is an independent predictor of postresection survival and local recurrence in PDAC after NAT. Achieving R0 resection with a margin of at least 1 mm should be a primary goal in the surgical treatment of PDAC after NAT.