Prognostic significance of extranodal extension of nodal metastasis in adenocarcinoma of the ampulla of Vater.

Although nodal metastasis (NM) is an important prognostic factor of ampullary adenocarcinoma, the prognostic implication of extranodal extension (ENE) is not well characterized. NM with ENE status was investigated in 279 surgically resected ampullary adenocarcinoma patients and compared with other clinicopathologic factors, including overall survival (OS) and recurrence-free survival (RFS). Expression of epithelial-mesenchymal transition (EMT) markers, including E-cadherin, Twist, and Snail, was assessed in a subset of the cohort. NM was observed in 94 cases (33.7%), of which ENE was observed in 32 cases (34%). NM with ENE was more frequently associated with tumors with poor differentiation than NM without ENE (P = .017). The 5-year OS and RFS rates of patients with NM and ENE was significantly worse (13.0% and 6.3%) than those with NM without ENE (37.7% and 21.4%) and those without NM (57.6% and 50.2%, respectively; P < .001). When pN category was matched, the OS and RFS was worse in patients with ENE than in those without ENE (P < .05). Moreover, the expression of E-cadherin and Twist was significantly different between NM areas with and without ENE (all, P < .001). Since ENE was associated with poorly differentiated ampullary adenocarcinomas and showed different expression of EMT markers, EMT could be a possible mechanism of ENE. Ampullary adenocarcinoma patients with ENE had worse OS and RFS than those without ENE. Therefore, evaluation of ENE can provide additional survival information for patients with surgically resected ampullary carcinoma.