Incremental Prognostic Information Beyond Nodal Positivity: The AJCC 8th Edition N1/N2 Subdivision and the Lymph Node Ratio in Resected Periampullary Adenocarcinoma

Background/Objectives: The American Joint Committee on Cancer (AJCC) 8th edition subdivides node-positive periampullary adenocarcinoma into N1 and N2 by the number of positive nodes. We quantified how much this subdivision and the lymph node ratio (LNR) each add to nodal positivity, and how the nodal yield affects the comparison.

Methods

This retrospective cohort comprised 147 consecutive pancreatoduodenectomies for pancreatic head (n = 49), distal bile duct (n = 63), ampullary (n = 31) or duodenal (n = 4) adenocarcinoma. In covariate-adjusted Cox models stratified by origin, the N1/N2 subdivision and the LNR were tested over nodal positivity and over each other with nested likelihood-ratio tests, overall, with the examined-node count in the model and by the period of resection.