Background: Characteristics of a cancer-positive margin around a resected uncinate process of the pancreas (MUP) due to a pancreticoduodenectomy are difficult to understand by standardized evaluation because of its complex anatomy. The purposes of this study were to subclassify the MUP with tissue marking dyes of different colors and to identify the characteristics of sites that showed positivity for cancer cells in patients with pancreatic head carcinoma who underwent circumferential superior mesenteric arterial nerve plexus-preserving pancreaticoduodenectomy. Results of this evaluation were used to review operation procedures and perioperative methods.
Method: We divided the MUP into 4 sections and stained each section with a different color. These sections were the pancreatic head nerve plexus margin (Area A), portal vein groove margin (Area B), superior mesenteric artery margin (Area C), and left of the superior mesenteric artery margin (Area D). The subjects evaluated were 45 patients who had carcinoma of the pancreatic head and were treated with circumferential superior mesenteric arterial nerve plexus-preserving pancreaticoduodenectomy.
Results: Of the 45 patients, nine cases (90%) of incomplete resection showed cancer-positivity in the MUP. Among the 4 sections of the MUP, the most cases of positive results [MUP (+) ] were found in Area B, with Area A (+), 0 case; Area B (+), 6 cases; Area C (+), 2 cases; and Area D (+), 3 cases (total, 11 sites in 9 patients). Relapse occurred in 7 of the 9 patients with MUP (+). Local recurrence was observed as initial relapse in all 3 patients with Area D (+). In contrast, the most common site of recurrence other than that in patients with Area D (+) was the liver.
Conclusion: By subclassifying the MUP with tissue marking dyes of different colors, we could confirm regional characteristics of MUP (+). As a result, circumferential superior mesenteric arterial nerve plexus-preserving pancreticoduodenectomy was able to be performed in R0 operations in selected patients while a better postoperative quality of life was maintained. Furthermore, Area D (+) represents an extension beyond the limit of the local disease and may indicate the need for early aggressive adjuvant chemotherapy.