Prospective assessment of resection margin status following pancreaticoduodenectomy for pancreatic ductal adenocarcinoma after standardisation of margin definitions.

Using an R1 definition of <1 mm and standardised pathology we demonstrate that R1 rates in PDAC can approach 90%. R1 = 0 mm remained an independent prognostic factor for overall survival. Using R1<1 mm we have shown that involvement of medial margins and multiple margins has significant negative impact on overall survival. We conclude that not all margin positivity has the same prognostic significance.