Intraoperative lymphatic mapping and the sentinel node concept in colorectal carcinoma

Background: Orderly progression of nodal metastases has been described for melanoma and breast cancer. The first draining lymph node, the sentinel nod e, is also the first to contain metastases and accurately predicts nodal st atus. The aim of this study was to assess the feasibility of lymphatic mapp ing and sentinel node biopsy in colorectal cancer. Methods: In 50 patients with colorectal cancer patent blue dye was injected around the tumour. After resection of the tumour the specimen was examined to identify blue-stained lymph nodes. Routine histopathological examinatio n was performed on all nodes and the blue, haematoxylin and eosin-stained t umour-negative nodes were tested immunohistochemically. Results: Lymphatic mapping was possible in 35 of 50 patients (70 per cent). Pathological examination with haematoxylin and eosin staining showed lymph node metastases in 20 of 35 patients. In eight of these 20 patients the bl ue nodes showed tumour, while in 12 the blue nodes were not involved. This represents a false-negative rate of 60 per cent. Conclusion: Lymphatic mapping using patent blue dye is feasible in colorect al cancer. The blue-stained nodes do not predict nodal status of the remain ing lymph nodes in the resected specimen. The concept of lymphatic mapping and sentinel node identification is not valid for colorectal cancer.