D1 Distal Pancreatectomy for Left-sided Pancreatic Ductal Adenocarcinoma Is Justifiable: A Propensity-score Matched Multicenter Study

Background/Aim: Evidence on the optimal extent of lymph node dissection for left-sided pancreatic ductal adenocarcinoma (PDAC) is scarce. The aim of the current study was to compare the long-term outcomes of patients who underwent D1 distal pancreatectomy (DP) with D2 DP for left-sided PDAC. Patients and Methods: Patients undergoing DP for left-sided PDAC at the four institutions affiliated to The Jikei University were enrolled in this study. Patients were divided into D1 and D2 groups. Patients' clinical characteristics, overall survival (OS), and relapse-free survival (RFS) were compared between the two groups before and after propensity-score matched (PSM) analysis. Results: Of 145 patients with left-sided PDAC, 55 patients underwent D1 DP and 90 underwent D2 DP, of whom 38 matched pairs were included in the PSM analytic cohort. In the unmatched cohort, no significant difference was found between the D1 and D2 groups for both OS (median 2.51 vs. 3.07 years; p=0.709) and RFS (median 1.47 vs. 1.27 years; p=0.565). After PSM, OS (median 2.37 vs. 3.56 years; p=0.407) and RFS (median 1.35 vs. 1.11 years; p=0.542) were not significantly different between the two groups. In a comparison of regional and systemic recurrence sites, no significant difference was observed between the two groups (p=0.500). Conclusion: The long-term survival of D1 DP for left-sided PDAC was not inferior to D2 DP. In an era in which the importance of multidisciplinary treatment for PDAC has been documented, unnecessary extended surgery should be avoided.