Prognostic assessment of different lymph node staging methods for pancreatic cancer with R0 resection: pN staging, lymph node ratio, log odds of positive lymph nodes

Abstract

Background and aims: Survival after surgical resection of pancreatic adenocarcinoma is poor. Several prognostic factors such as the status of the resection margin, lymph node status, or tumour grading have been identified. The aims of the present study were to evaluate and compare the prognostic assessment of different lymph nodes staging methods: standard lymph node (pN) staging, metastatic lymph node ratio (LNR), and log odds of positive lymph nodes (LODDS) in pancreatic cancer after pancreatic resection.

Materials and methods: Data were retrospectively collected from 143 patients who had undergone R0 pancreatic resection for pancreatic ductal adenocarcinoma. Survival curves (Kaplan-Meier and Cox proportional hazard models), accuracy, and homogeneity of the 3 methods (LNR, LODDS, and pN) were compared to evaluate the prognostic effects.

Results: Multivariate analysis demonstrated that LODDS and LNR were an independent prognostic factors, but not pN classification. The scatter plots of the relationship between LODDS and the LNR suggested that the LODDS stage had power to divide patients with the same ratio of node metastasis into different groups. For patients in each of the pN or LNR classifications, significant differences in survival could be observed among patients in different LODDS stages.

Conclusion: LODDS and LNR are more powerful predictors of survival than the lymph node status in patients undergoing pancreatic resection for ductal adenocarcinoma. LODDS allows better prognostic stratification comparing LNR in node negative patients.

Keywords: LODDS; Log odds of positive lymph nodes; Lymph node metastasis; Lymph node ratio; Pancreatic cancer surgery; pN staging.