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

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.