O125 The impact of R0 versus R1 resection on survival after surgery for pancreatic cancer and distal cholangiocarcinoma

Abstract

Abstract Introduction Pancreatic ductal adenocarcinoma (PDAC) and distal cholangiocarcinoma are characterised by poor overall survival, even after curative resection. We sought to determine if R0 versus R1 status affected survival. Methods This retrospective study included patients who underwent pancreatic resection for PDAC or distal cholangiocarcinoma between Jan 2001 and Dec 2021 at a tertiary HPB unit in the UK. Demographic characteristics and operative outcomes were compared using chi-squared testing and Mann Whitney-U test. The overall survival was determined using Kaplan-Meier survival curves with the log-rank test used to estimate the equality of survival between patients with R0 and R1 resections. Results In total 191 patients were included, of whom 87 (45.5%) hade R0 resections and 104 (54.5%) were R1 resections. There were no significant differences in demographic characteristics such as age (p=0.5186), gender (p=0.146) and morbidity (p=0.947). The location of tumour and operative procedure also did not differ between R0 and R1 resections. There were however significant differences in the size of tumour, median (IQR) 26 (20-36.5) mm in R0 and 30 (25-40) mm in R1 resections and the total number of lymph nodes excised 12 (8-16) vs 15 (11-19), p=0.0049 in R0 and R1 resections respectively. The total positive lymph nodes were also higher in R1 resection with 2 (1-5) nodes compared with 0 (0-2) nodes, p=0.0001. The overall median survival was shorter after R1 resections [1.53 years (0.67-2.72) v 2.40 years (1.15-4.85), p=0.0046]. Conclusion The tumour margin status directly impacts overall survival in patients with pancreatic cancer.