Prognostic importance of numbers of retrieved lymph nodes and positive lymph nodes for ampulla of vater cancer (AVC) in 2347 patients from the Surveillance, Epidemiology, and End Results (SEER) database

INTRODUCTION: The numbers of retrieved lymph nodes (RLNs) and positive lymph nodes (PLNs) had a significant impact on the survival of patients with ampulla of vater cancer (AVC), but the optimal numbers of the both were controversial. OBJECTIVE: The cohort study aimed to explore the prognostic value and the optimal point of RLNs and PLNs for AVC. METHODS: A total of 2347 AVC patients with M0 disease who underwent surgical resection and lymph node dissection from January 2004 to December 2013 were acquired from a prospective database. RESULTS: The study found that the optimal cut-off values of RLNs were 18 in the N0 cohort and 16 in N1 or entire cohort due to the highest 5-year overall survival (OS) rate and disease-specific survival (DSS) rate and the separation of survival curves (all P < 0.05). In patients with RLNs ≥ 16, patients with PLN = 0 demonstrated significantly better 5-year OS and DSS rates (70.9% and 77.1%) compared to those with PLNs = 1–2 (41.6% and 44.7%; all P < 0.001), and patients with PLNs = 1–2 demonstrated significantly better 5-year OS and DSS rates (41.6% and 44.7%) compared to those with PLNs ≥ 3 (24.3% and 28.0%; all P < 0.001). CONCLUSIONS: This article recommended that at least 16 lymph nodes will improve the prognosis of AVC patients undergoing surgery. The best cut-off values of PLNs recommended for this study were 0 and 2, which may accurately stratify patients.