Sentinel lymph node mapping in colon cancer

Background: By systematically reviewing the literature on sentinel lymph node mapping of colon cancers, this study aimed to evaluate this technique as it applies to colon cancers. Methods: Human studies on lymphatic mapping for colon cancers were reviewed. Multiple publications of the same studies, abstracts, and case reports were excluded. Current Contents, MEDLINE, EMBASE, and Cochrane Library databases were investigated. Results: Lymphatic mapping appears to be readily applicable to colon cancers, identifying lymph nodes most likely to harbor metastases. Identification of sentinel lymph nodes varied from 58% to 100% and carried a false-negative rate of approximately 10% in larger studies, but potentially rose 4% to 25% among patients representing a range from node-negative to node-positive (micrometastases) conditions. The prognostic implication of these micrometastases requires further evaluation. Lymphatic mapping in 6% to 29% of cases identified aberrant lymphatic drainage that altered the extent of the lymphadenectomy. Conclusions: Further follow-up evaluation to assess the prognostic significance of micrometastases for colon cancers is required before the staging benefits of sentinel node mapping can have therapeutic implications. Lymphatic mapping offers the possibility of improving staging by identifying patients with early disseminated disease who should be considered for adjuvant treatment or included in trials of adjuvant treatment to speed up the breakthrough of more effective adjuvant regimens. Large studies are needed to determine whether the sentinel node concept is as valid for colon cancers as studies so far have shown it is for malignant melanoma and breast cancer.