BACKGROUND Lymph node (LN) metastasis is an important prognostic factor in the ampulla of Vater (AoV) adenocarcinoma. Various LN parameters have been proposed, but their prognostic efficacy has not been compared in the same population. We aimed to evaluate the prognostic values of LN parameters in AoV adenocarcinoma patients who underwent surgical resection and adjuvant treatment based on the long-term follow-up data.

METHODS A total of 86 patients with surgically resected AoV adenocarcinoma followed by adjuvant treatment were analyzed. We evaluated the prognostic values of various LN parameters such as pathologic N stage, number of metastatic regional LN (LNN), LN ratio (LNR), and log odds of positive LNs (LODDS). Each LN parameter was separately analyzed using Cox regression models with the same confounders.

RESULTS The median follow-up period was 69.4 months, and the median overall survival (OS) was 114 months. The median number of dissected LNs is 15, with an interquartile range of 8 to 25. In the univariable analyses, all LN parameters showed significant prognostic efficacy for OS, disease-free survival (DFS), and distant metastasis-free survival (DMFS). In the multivariable Cox regression analyses, LNN ≥ 2 was a statistically significant prognostic factor for OS (hazard ratio (HR) 2.10, 95% confidence interval (CI), 1.11-3.97; p = 0.022), DFS (HR 2.51, 95% CI 1.28-4.93; p = 0.007), and DMFS (HR 2.74, 95% CI 1.39-5.41; p = 0.004). LNR showed significant prognostic performance for DFS (HR 2.35, 95% CI 1.23-4.50; p = 0.010), and DMFS (HR 2.26, 95% CI 1.17-4.35; p = 0.015). N stage showed significant prognostic performance in DFS (HR 1.55 for pN1; p = 0.243 and HR 4.31 for pN2; p = 0.003), DMFS (HR 1.46 for pN1; p = 0.323 and 4.59 for pN2; p = 0.002). LODDS and the presence of LN metastasis, did not demonstrate significant prognostic value across survival outcomes.

CONCLUSIONS LN parameters showed good long-term predictive performance in AoV adenocarcinoma patients treated with curative resection and adjuvant treatments. Among LN parameters, LNN ≥ 2 showed better prognostic value than others. Further large-scale studies are needed to validate the clinical usefulness of various LN parameters.