En bloc proximal peri-mesenteric clearance for pancreatic head cancer surgery.

The superior mesenteric artery (SMA) first approach and meso-pancreas excision (MPE) during pancreatoduodenectomy (PD) for pancreatic head cancer have been suggested for complete local tumor control, less operative blood loss, and early determination of resectability. However, SMA-first approach is merely a mode of approach and the concept of MPE has been challenged due to its anatomical obscurity. Dissection around proximal mesenteric vessels, superior mesenteric vein and SMA, is a critical procedure point for local tumor control as tumor infiltration is frequently observed both at the time of initial diagnosis and recurrence. The meso-pancreas, which encompasses the soft tissue between the uncinated process and SMA, does not include all the aforementioned points of proximal mesenteric areas. Therefore, the authors propose a new terminology named, "en bloc proximal peri-mesenteric clearance (PPMC)", to describe the removal of all the lymph nodes including soft tissue around proximal mesenteric vessels, especially the SMA, to ensure complete local tumor control of pancreatic head cancer. The SMA-first approach applied either by the mesenteric approach or supra-colic approach can make this procedure more feasible. The extent of the circumferential dissection of the peri-SMA nerve plexus can be adjusted according to the primary disease. PPMC including the removal of all lymph nodes around the proximal SMA may be considered as a standard extent of PD for pancreatic head cancer.