LAUSR

The AJCC 8th edition defines microscopic positive margin (R1) as cancer cells within 1 mm of the pancreatic resection margin. The pancreatic resection margin most amenable to re-resection is the pancreatic neck margin. A large multi-institutional study from the U.S. reported association with worse overall survival for patients who were converted to R0 with re-resection after R1 on frozen section compared with R0 margin on permanent section without re-resection (HR 1.55, p = 0.009). In contrast, another large study between two institutions (one in the U.S. and another one in Italy) reported association with improved survival on re-resection after R1 on frozen section (24 months vs. 10 months, p = 0.02) by using the definition of positive margin as direct margin (0 mm) instead of the AJCC 8th edition ([ 1 mm). The controversy of re-resecting intraoperative positive pancreatic resection margins continues to exist. Based on the available data, it is reasonable to forego intraoperative neck margin assessment, or consider re-resection for an additional single margin if resection margins are evaluated and positive intraoperatively without rechecking further. The initial positive margin probably indicates tumor biology rather than surgical inadequacy and extended pancreatic resections may not impact survival. The impact on survival with conversion of an intraoperative positive margin to a negative margin by extending the pancreatic resection has not been adequately evaluated in the cohort of patients subjected to neoadjuvant therapy.