Frequency and prognostic significance of occult tumor cells in lymph nodes in patients with adenocarcinoma of the papilla of Vater

Background: Occurrence of tumor relapse is frequent in patients with carcinoma of the papilla of Vater despite the absence of residual tumor detectable at primary surgery. Therefore it has to be assumed that current tumor staging procedures fail to identify minimal amounts of tumor cells disseminated to secondary organs, which might be precursors of subsequent metastatic relapse. The aim of the study was to assess the frequency and prognostic impact of minimal tumor cell spread in lymph nodes classified as 'tumor-free' in routine histopathologic evaluation. Materials and methods: A total of 41 'tumor-free' lymph nodes from 23 patients with adenocarcinoma of the papilla of Vater who underwent curative tumor resection (R0) were examined by immunohistochemistry with the monoclonal anti-EpCAM antibody Ber-EP4 for minimal disseminated tumor cells. Results: Twelve (29.3%) of the 41 'tumor-free' lymph nodes obtained from 9 (39.1%) of the 23 patients displayed EpCAM-positive cells. Kaplan-Meier survival analysis revealed that patients with EpCAM-positive cells in lymph showed a clearly reduced relapse-free and overall survival compared with patients without such cells. However, these differences were not statistically significant (p= 0.13 for relapse-free survival, p= 0.11 for overall survival). Discussion: Immunohistochemical assessment may refine the staging of resected lymph nodes in patients with carcinoma of the papilla of Vater. However, the presence of minimal disseminated tumor cells in lymph nodes had no significant impact on the prognosis in these patients.