The Revised R Status is an Independent Predictor of Postresection Survival in Pancreatic Cancer After Neoadjuvant Treatment

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.