Reappraisal of Nodal Staging and Study of Lymph Node Station Involvement in Pancreaticoduodenectomy with the Standard International Study Group of Pancreatic Surgery Definition of Lymphadenectomy for Cancer

BACKGROUND:The prognostic role of lymph node (LN) dissection in pancreatic head ductal adenocarcinoma is still unclear. This study reappraised the value of the number of positive LNs and LN ratio in patients undergoing pancreaticoduodenectomy with standard lymphadenectomy according to the recent International Study Group of Pancreatic Surgery definition. In addition, the impact of nodal metastases stratified by LN stations was investigated.STUDY DESIGN:After reviewing retrospectively clinical and pathologic data of 758 pancreaticoduodenectomies for pancreatic head ductal adenocarcinoma performed from 2002 through 2011, we extracted patients in whom the LN stations included in the International Study Group of Pancreatic Surgery definition had been sampled. Survival analysis was performed using univariate and multivariate models.RESULTS:The study population consisted of 255 patients. Mean number of harvested LNs was 30.8. Factors with a significant prognostic impact on multivariate analysis were tumor grade, adjuvant therapy, number of positive LNs, LN metastases along station 14a-b (proximal superior mesenteric artery), and the number of metastatic LN stations. Patients with involvement of station 14a-b exhibited worse pathologic features, indicating more aggressive disease.CONCLUSIONS:In patients receiving a uniform LN dissection, the number of positive LNs is superior to LN ratio for predicting survival. Lymph node metastases along the proximal superior mesenteric artery have a significant prognostic value, and an increasing number of metastatic stations are associated with a sharp decrease in survival. In future studies, clarification of the pattern of LN metastasis spread could offer valuable insight into the optimal treatment strategies, including selection of patients for neoadjuvant therapies.