Role of the lymph node ratio in pancreatic ductal adenocarcinoma. Impact on patient stratification and prognosis.

Background: Survival after resection of pancreatic adenocarcinoma is poor. Several prognostic factors such as the status of the resection margin, lymph node status, or tumor grading have been identified. Aim of the study was to evaluate the prognostic significance of the lymph node ratio (LNR) for resected pancreatic ductal adenocarcinoma.

Materials And Methods: Data were collected from 101 patients who had undergone pancreatoduodenectomy for pancreatic ductal adenocarcinoma. Patients were divided into four groups according to the absolute LNR (0, 0-0.199, 0.2-0.399, >0.4). Kaplan-Meier and Cox proportional hazard models were used to evaluate the prognostic effect.

Results: The actuarial 3- and 5-year survival rates were 32 and 17%, respectively. The median survival was 19 months. Patients with LNR 0/0-0.199/0.2-0.399/>0.4 survived 40.2/30.5/18.1, and 13.6 months, respectively (P = 0.001). At the multivariate analysis, lymph node status was not found to be a significant prognostic factor; on the contrary LNR >0.2 (P = 0.007), positive resection margin (P = 0.001), and grading (P = 0.05) were significantly related to survival.

Conclusion: LNR is a more powerful predictor of survival than the lymph node status in patients undergoing pancreaticoduodenectomy for ductal adenocarcinoma.