Prognostic implications of resection margin status in distal pancreatectomy for pancreatic ductal adenocarcinoma.

Background: Curative resection is a well known prognostic factor in pancreatectomy. However, definition and clinical significance of resection margin in distal pancreatectomy remains controversial.

Methods: From 2010 to 2018, 203 patients with pancreatic cancer undergoing distal pancreatectomies were included. Patients were classified into three groups: R0-wide (tumor-free margin ≥1 mm), R0-narrow (0 mm < tumor-free margin <1 mm), and R1 margin (tumor-free margin = 0 mm). We also evaluated the prognostic impact of individual margins (transection, anterior, and posterior).

Results: Patients with an R0-wide margin (36.6 %) exhibited superior 5-year disease free survival rate compared to those with R0-narrow (30.4 %, p = 0.059) or R1 margin (0.1 %, p = 0.014). However, in multivariate analyses, only R1 margin (hazard ratio [95 % confidence interval], 2.02 [1.32-3.12]; p = 0.001), unlike R0-narrow margin (1.17 [0.78-1.77]; p = 0.446), was linked to shorter overall survival compared to R0-wide margin. In multivariate analyses, posterior margin involvement was uniquely identified as a poor prognostic factor (1.83 [1.07-3.13]; p = 0.027).

Conclusions: The 0 mm rule seems more suitable than the 1 mm rule for predicting prognosis in performing distal pancreatectomy, and especially, achieving microscopically negative posterior margin is crucial.