The clinical significance of the lymph node ratio as a recurrence indicator in ampullary cancer after curative pancreaticoduodenectomy.

Background: The clinical significance of the lymph node ratio (LNR), the number of metastatic lymph nodes per dissected lymph node, has not been sufficiently clarified in ampullary cancer.

Methods: Among patients diagnosed histopathologically with ampullary cancer between 1980 and 2018, the study included 106 who underwent pathological radical resection by pancreaticoduodenectomy. The relationships between the LNR and metastatic lymph node sites and prognosis were examined.

Results: Multivariate analysis revealed that sex and lymph node metastasis were independent prognostic factors. In the 46 patients (43%) with metastatic lymph nodes, the LNR in the recurrence group was significantly higher than that in the non-recurrence group (0.15 ± 0.11 vs. 0.089 ± 0.071, p = 0.025). The receiver operating characteristic curve demonstrated that the LNR cut-off value, 0.07 (area under the curve = 0.70, sensitivity 81%, specificity 56%), was a significant indicator for recurrence (22% vs. 61%, p = 0.016) and prognosis (5-year survival: 48% vs. 83%, p = 0.028). Among the metastatic lymph node sites in the 46 positive cases, lymph node metastases developed from the peripancreatic head region (80%, 37/46) to the superior mesenteric artery (33%, 15/46) and para-aortic (11%, 5/46) regions.

Conclusion: Lymph node metastasis is an independent prognostic factor, and the LNR is a significant indicator for recurrence and prognosis in patients with ampullary cancer.