Abstracts
2000 Digestive Disease Week

# 2248 Detection of Lymph Node Micrometastases in Esophageal Carcinoma: Pathology of Lymph Node Involvement.
Marcus Feith, Hubert J. Stein, James Mueller, J. Ruediger Siewert, Munich, Germany

Introduction: Lymph node microinvolvement has been identified as prognostic factor in a variety of epithelial tumors. No comperative data is available on adenocarcinoma and squamous cell carcinoma of the esophagus. Material and Methodes: We investigated 73 patients with adenocarcinoma of the distal esophagus and 69 patients with squamous cell carcinoma of the esophagus who were primary R0-resected in our department. 3718 removed lymph nodes were assessed immunhistochemically with the antibody cocktail AE1/AE3 and the antibody Ber-EP4 to identify epithelial tumor cells. Newly identified single tumor cells and tumor cell clusters <0.2mm in diameter with stromal reaction were classified as micrometastases. Results: On standard histopathologic evaluation there was no evidence of lymph node metastases in 41 of 73 patients with adenocarcinoma and 41 of 69 patients with squamous cell carcinoma of the esophagus. Immunhistochemical analysis showed lymph node micrometastases in 9.7% of patients with adenocarcinoma staged as pN0 compared to 31.7% of the patients with squamous cell carcinoma (p<0.05). Lymph node micrometastases were found in none of the 28 patients with adenocarcinoma staged pT1N0 in contrast to 6/24 patients with a pT1N0 staged squamous cell carcinoma (p<0.05). On multivariante analysis the presence of micrometastases had a significant impact on survival in patients with squamous cell carcinoma (p<0.05), but not in patients with adenocarcinoma. Conclusion: In contrast to patients with squamous cell carcinoma, micrometastases in lymph nodes staged pN0 on routine histologic examination are uncommon in patients with adenocarcinoma of the distal esophagus and appear to have no significant impact on survival. This suggests a different biology of lymph node metastases and supports the concept of different strategies for lymphadenectomy in these two tumor entities.