Lymph Node Evaluation for Pancreatic Adenocarcinoma and Its Value as a Quality Metric

Background: Adequate lymph node evaluation (LNE) is recommended for surgically treated pancreatic adenocarcinoma because studies have shown an association between improved survival and adequate LNE. This study aimed to understand the mechanism of this association and determine whether LNE is a valuable quality metric. Methods: Using the linked Surveillance Epidemiology End Results Medicare database, we identified patients with surgically treated pancreatic adenocarcinoma from 2000 to 2010. Adequate LNE was defined as evaluation of ≥15 nodes. Survival was determined using Kaplan-Meier and Cox proportional hazards. Results: We identified 2629 patients who underwent resection for pancreatic adenocarcinoma. Overall, 33 % had adequate LNE. Adequate LNE was significantly associated with receipt of postoperative chemotherapy. A significant decrease in hazard of death was associated with adequate LNE (HR 0.86, p < 0.05). Receipt of postoperative chemotherapy was also significantly associated with decreased hazard of death (HR 0.77, p < 0.05). On unadjusted analysis, the survival benefit associated with adequate LNE was lost when stratified by receipt of postoperative chemotherapy. Conclusion: The survival benefit associated with LNE is in part derived from the fact that patients who receive adequate LNE are also more likely to receive chemotherapy. Thus, the use of lymph node counts has limitations as a quality metric.