Lymph node ratio as parameter of regional lymph node involvement in pancreatic cancer.

Abstract

To determine which indicators, anatomical nodal metastasis (Japan Pancreas Society, JPS), number of positive lymph nodes (PLN), or lymph node ratio (LNR), is the best means of assessing lymph node involvement in pancreatic cancer. This retrospective study analyzed 275 patients with pancreatic cancer treated at a single institution. Survival curves according to the JPS, PLN, or LNR were assessed by the Kaplan-Meier method. Prognostic value of each classification was explored by Cox regression analysis after adjustments for clinical factors. Multivariate analysis showed that, relative to n0 in the JPS, hazard ratios (HR) in n1, n2, and n3 were 1.72, 1.73, and 2.75, respectively, with no difference in survival between n1 and n2. Relative to PLN of 0, the HR in the PLN categories of 1∼2, 3, and >3 were 1.39, 1.65, and 3.03, respectively. Relative to LNR of 0, the HR in the categories of 0 < LNR ≤ 0.1, 0.1 < LNR ≤ 0.2, and LNR > 0.2 were 1.27, 2.00, and 5.58, respectively. An incremental increase in the HR was observed as the LNR category progressed, and differences between the survivals were distinct when stratified by the LNR. The LNR was an accurate predictor of survival among three assessment strategies and could be proposed as a candidate for use as N categories, pending validation studies.