[Impact of the sentinel lymph node in the staging of colorectal carcinoma].

In view of the very good results obtained by lymphatic mapping and sentinel node biopsy in the staging of patients with melanoma or breast cancer, we investigated the feasibility of intraoperative regional lymphatic mapping in patients with primary colorectal carcinoma. The aim of this study was to determine whether lymphatic mapping and sentinel node assessment can identify aberrant drainage patterns or make for better staging of the neoplasm in those cases with no or only minimal lymphatic neoplastic involvement. Sixteen consecutive patients with primary colorectal cancer (stage T2-T3) but without macroscopic involvement of the lymphatic system underwent intraoperative lymphatic mapping by injecting 1-1.5 ml of isosulfan blue dye. The identified and resected sentinel nodes were examined using conventional haematoxylin-eosin staining and cytokeratin immunohistochemistry. Sentinel node identification was successful in 15 out of 16 cases (93.8%). In 11 cases (73.3%) sentinel node status correctly predicted the final staging. The false-negative rate was 26.7%. Immunohistochemical analysis revealed the presence of micrometastasis in one case (6.7%), which was consequently upstaged. In cases of colorectal cancer lymphatic mapping is an easy, perfectly feasible technique. However, in our experience, it would not appear to significantly improve the accuracy of the histopathological staging of colorectal carcinoma.