Is lymph-node micrometastasis in gallbladder cancer a significant prognostic factor?

Abstract

Background/aims: The purpose of our study was to investigate prognostic significance of lymph-node micrometastasis in gallbladder carcinoma.

Methodology: In total, 1,094 lymph nodes from 41 patients who had undergone radical resection with lymph-node dissection, including para-aortic lymph nodes were stained with hematoxylin and eosin (H&E) and immunostained with anti-cytokeratin 7/8 antibody. Micrometastasis in each lymph node was defined as tumor cells that were detectable only by immunohistochemical evaluation and were not detected by H&E staining.

Results: Metastases were detected in 163 lymph nodes (14.9%) by H&E staining. Micrometastases were found in 25 of the remaining lymph nodes (2.3%). Among 24 patients with lymph node metastasis based on the H&E staining, 12 had micrometastases. Of the 17 patients in whom lymph-node metastasis was not detected by the H&E staining, one was found to have micrometastasis. Micrometastasis correlated significantly with lymph node metastasis on H&E staining and pN (Tumor-Node-Metastasis 5th ed.). On multivariate analysis of data from 17 node-positive patients who underwent curative resection, micrometastasis and microscopic venous invasion were significant prognostic factors.

Conclusions: Our findings suggest that micrometastasis might be traces of scatter of cancer cells to the whole body rather than an event in an initial stage of the metastasis.