Objectives: Pylorus preserving pancreatoduodenectomy (PPPD) was introduced to achieve a better functional result compared with the conventional Kausch-Whipple procedure (PD). In PPPD, peripyloric and perigastric lymphatic tissue is not removed compared with PD. The aim of this prospective study was to identify the frequency of peripyloric and perigastric lymph node metastases in ductal adenocarcinoma of the pancreatic head (PC). Methods: Fifty specimens following Kausch-Whipple procedure including partial gastric resection for PC were analyzed for peripyloric and perigastric lymph node metastases by a standardized clearing technique. All lymph nodes of the specimens were counted, discriminating between those not removed ("group A") and those removed ("group B") in pylorus preserving resection of the pancreatic head. Additionally, the duodenal wall and paraduodenal tissue at a potential duodenal resection margin 2 cm distal of the pylorus were investigated histologically. Results: Three of the 50 specimens (6%) carried peripyloric lymph node metastases, whereas 32 of the 50 specimens (64%) contained lymph node metastases in total. Four of 362 group A and 90 of 748 group B lymph nodes showed metastatic spread of the carcinoma. The 4 lymph node metastases in group A could be identified exclusively in 88 peripyloric lymph nodes but in none of the 274 perigastric lymph nodes at the lesser or greater curvature. In 2 of the 3 patients with peripyloric lymph node metastases, these lymph nodes were the only lymph nodes with metastatic involvement in the entire specimen. In 1 specimen, a small tumor nest of less than 2 mm in diameter was detected at a distance of less than 1 mm to the pylorus, although pyloric involvement was not suspected intraoperatively. The potential PPPD resection margin of the duodenal wall was not infiltrated by intramural tumor spread in any specimen. Conclusion: In a minority of 6%, PC metastasizes in peripyloric lymph nodes. Lymph nodes of the lesser and greater curvature of the stomach are not involved in patients with PC. Thus, we conclude by the data of this prospective study that the limited benefits of the extended lymph node dissection in a conventional Kausch-Whipple resection are far outweighed by the disadvantages construed by this procedure.
