Should sentinel lymph node mapping be performed for colorectal cancer?

Correct determination of lymphatic nodal statement is essential to stage correctly and to predict survival. As it is vital to make an assessment about the adjacent lymph node(s), this study was designed to compose a sensitive detection on the sentinel lymph nodes (SLN) indicating tumoral lymphatic basin using advanced pathologic examination.From June 2002 to June 2003, this prospective study was performed in 41 patients undergoing standard resection for colorectal cancer. In this study we employed the ex-vivo SLN mapping technique.At least one SLN in 37 of 41 patients was identified (90.2%). The lymph nodes (LN) from those patients were studied by hematoxylin and eosin dye (HE) and multisectioning. Twenty of 37 patients with trace of the metastasis were found. The remaining 17 patients without any metastatic LN by HE underwent clarification of micrometastases (MM) using immunohistochemical (IHC) staining technique. Two patients (11.7%) had MM in the SLN(s). Upstaging was evaluated in those two. The sensitivity of SLNs was obtained as 90%. Two patients with no metastatic SLN had metastasis in the non-sentinel LNs.In the LNs from the basin of tumor, MM exposed by IHC staining was still not obvious to indicate poor prognosis. The need for treatment adjustment in those patients is clear since the upstaging was evident.