Lymph Node Yield Is Associated With Improved Overall Survival and Increased Time to Recurrence in Node-Negative Pancreatic Ductal Adenocarcinoma Following Neoadjuvant Therapy.

Abstract

To determine whether lymph node yield (LNY) is associated with improved overall survival (OS) and time to recurrence (TTR) in patients with node-negative pancreatic ductal adenocarcinoma (PDAC) treated with neoadjuvant therapy (NAT). LNY has been associated with survival in solid gastrointestinal cancers, including PDAC. Patients with pathologic T stage I to III, node-negative (N0), PDAC treated with NAT followed by pancreatoduodenectomy were identified in the Massachusetts General Hospital pancreatectomy database and the National Cancer Database (NCDB). A cutoff point of 22 nodes was identified in the NCDB using the point with the optimal (log-rank test) split. OS and TTR were evaluated using univariate and multivariable analyses. In the Massachusetts General Hospital cohort, 233 node-negative patients following NAT were included. A LNY ≥ 22 was associated with prolonged median OS (59 vs 25 mo, P <0.001) and prolonged TTR (32 vs 14 mo, P =0.019). On multivariable analysis, LNY was an independent predictor of survival (HR 0.97, 95% CI: 0.95-0.99, P =0.034) per sampled node. In the NCDB, 2029 node-negative patients following NAT were included. A LNY ≥ 22 was associated with prolonged median OS (49 vs 33 mo, P <0.001). On multivariable analysis, LNY was an independent predictor of survival (HR 0.99, 95% CI: 0.98-0.99, P <0.001) per sampled node. LNY was associated with improved oncologic outcomes in patients treated with NAT followed by pancreatoduodenectomy in two independent data sets. Responsible mechanisms by which LNY impacts the outcomes of node-negative patients following NAT warrant further exploration.