Cutaneous melanoma: therapeutic lymph node and elective lymph node dissections, lymphatic mapping, and sentinel lymph node biopsy

Abstract

Early clinical observation in cancer patients suggested that tumors spread in a methodical, stepwise fashion from the primary site, to the regional lymphatics, and only then to distant locations. Based on these observations, the regional lymphatics were believed to be mechanical barriers, at least temporarily preventing the widespread dissemination of tumor. Despite evidence now available disputing its validity, this barrier theory has guided the surgical management of the regional lymphatics in cancer patients for more than a century, influencing the use of such surgical modalities as therapeutic lymph node dissection, elective lymph node dissection, and most recently lymphatic mapping and sentinel lymph node biopsy. No published randomized controlled trial exists that demonstrates improved overall patient survival for cancer of any type, including melanoma, after surgical excision of regional lymphatics. This article will review the biology of lymphatics as it relates to regional tumor metastasis, and based on available information, offer practical recommendations for the clinical dermatologist and their patients who have cutaneous melanoma.