Pathobiology of the sentinel node

Purpose of review Lymphatic mapping and sentinel lymph node biopsy have been established as definitive procedures for the staging of cutaneous melanoma. Large-scale studies that have been recently conducted and that are ongoing suggest a therapeutic role for lymphatic mapping/sentinel node biopsy in the management and prognosis of melanoma patients with early lymph node metastases. Recent findings Sentinel node biopsy has been shown to extend disease free survival and increase melanoma-specific survival for patients with early nodal metastases according to interim analysis of the Multicenter Selective Lymphadenectomy Trial 1 (MSLT-1). The proper evaluation of sentinel lymph nodes requires histologic and immunohistochemical analysis of multiple levels. Immune modulation has been shown to play an important role in nodal metastasis. Summary There is increasing evidence for the efficacy of lymphatic mapping and sentinel lymph node biopsy in predicting prognosis, reducing the morbidity traditionally associated with regional lymph node dissection and increasing survival in subgroups of patients with cutaneous melanoma. Further study is needed to determine the role of the immune system in the spread of nodal metastases and the role of immunomodulatory therapy to prevent or possibly even reverse nodal metastases.