Importance of Nodal Metastases Location in Pancreatoduodenectomy for Pancreatic Ductal Adenocarcinoma: Results from a Prospective Lymphadenectomy Protocol

Introduction: The issue of nodal metastases location in upfront pancreatoduodenectomy (PD) for cancer is unclear. Implementing a prospective lymphadenectomy protocol, we investigated the nodal yields and metastases per anatomical stations and nodal echelon. Next, the relationship between the extension of nodal dissection, the number of examined/positive nodes (ELN/PLN), disease staging and prognosis was assessed. Methods: Lymphadenectomy included stations 5/6/8a-p/12a-b-c-p/13/14a-b/17 and jejunal mesentery nodes. Stations embedded in the specimen (13/14/17/jejunal mesentery) were defined as first-echelon, those sampled separately (5/6/8/12) as second-echelon. Recurrence and survival were analyzed. Results: Overall, 424 PDs (2013-2018) were enrolled. The median number of ELN and PLN was 42 (IQR 34-50) and 4 (IQR 2-8). Node-positive patients were 88.2%. The commonest metastatic sites were stations 13 (77.8%) and 14 (57.5%). Overall, 248 patients (58.5%) had metastases only in the first echelon, 4 (0.9%) only in the second, 122 (28.8%) in both. The median number of ELN and PLN in the first echelon was 28 and 4. Second-echelon nodes increased nodal counts by 10 ELN and 0 PLN, translating in only minor changes in staging. Nodal-related factors independently associated with recurrence and survival were N-status, multiple metastatic stations, metastases to station 14 and jejunal mesentery nodes (Table). The highest concordance was reached when including metastases location (c-index=0.769). Conclusion: First-echelon dissection provides an adequate number of ELN for optimal staging. Nodal metastases occur mostly at stations 13/14, although second-echelon involvement is frequent. Station 14 and jejunal mesentery nodes involvement is prognostically relevant. They should be included in the standard nodal map and analyzed pathologically.