Effect of resection margin status on recurrence pattern and survival in distal pancreatectomy for left-sided pancreatic ductal adenocarcinoma

Background: The association of resection margin status with recurrence and survival after pancreatectomy for pancreas ductal adenocarcinoma (PDAC) remains controversial. The aim of this study was to identify the effect of R1 resection on recurrence pattern and survival after distal pancreatectomy for left-sided PDAC. Methods: Patients who underwent distal pancreatectomy for PDAC at two high-volume institutions between January 2010 and December 2017 were retrospectively reviewed. Perioperative characteristics, pathological outcomes, recurrence pattern, and survival data were collected to compare R0 resection and R1 resection. Results: Among 558 patients who underwent distal pancreatectomy for PDAC, 158 patients (28.3%) showed R1 resection margin. R1 patients were associated with large tumor size (3.3 cm vs. 3.7 cm, p =.006) and lower number of positive lymph nodes (1.3 vs. 2.0, p =.001). Median overall survival (37.3 months vs. 20.1 months, p <.001) and recurrence-free survival (14.6 months vs. 6.9 months, p <.001) significantly differed between the R0 and R1 groups. Disease recurrence patterns were not statistically different between the two groups (p =.182). Among the recurrence patterns, peritoneal carcinomatosis had the shortest recurrence-free survival (5.6 months, p <.05) and overall survival (13.6 months, p <.05) compared with all other recurrence patterns. Conclusions: R1 resection margin after distal pancreatectomy was associated with poor survival and early recurrence. There is no significant difference in recurrence pattern between R0 and R1. Among the recurrence patterns, peritoneal carcinomatosis showed the worst prognosis.