Background: Metastasis in regional lymph nodes is one of the most important prognostic factors in colorectal cancer. Nevertheless, recurrence may be expected in about 20% of lymph-node-negative patients. Detection of the lymph node(s) most likely to contain potential metastases, denoted the sentinel node(s), would be expected to contribute to the identification of patients with poor prognosis even if they have no lymph node metastases detected by routine analysis.
Material and methods: The literature databases PubMed and EMBASE were systematically searched with combinations of the words "sentinel, lymph node, node, colon, colorectal, rectum, carcinoma and cancer". Relevant reviews and original articles among primary hits, and cross-references therein, were extracted for further study.
Results and interpretation: Mapping of sentinel lymph node(s) in patients with colorectal cancer is feasible. However, a standard histopathological analysis restricted to the sentinel lymph nodes is associated with too high false negative rates to be a realistic alternative to the present routine analysis of regional lymph nodes. New prospective studies are required to clarify whether immunohistochemical or molecular biological analysis of sentinel nodes can identify patients with a poor prognosis even though they have no lymph node metastases detected by routine analysis.