The role of elective lymph node dissection in melanoma: rationale, results, and controversies.

Elective lymph node dissection (ELND) for patients with clinically occult metastatic melanoma in regional lymph nodes has the goal of curing metastases with a surgical treatment. This is in contrast to the low probability for surgical cure in patients with clinically detectable lymph node metastases. The rationale for elective node dissection is based on a hypothesis that melanoma metastasizes sequentially via lymph nodes and then to distant sites. A subgroup of melanoma patients with high risk for regional node micrometastases but low risk for distant micrometastases has been identified from prognostic factors analysis of large patient series, as well as surgical results of nonrandomized clinical trials. However, two nonrandomized surgical trials have failed to show a survival benefit for ELND. These studies were largely performed in female patients with extremity melanomas and there were limitations that preclude a definitive conclusion. No randomized trials have been conducted involving melanomas of the trunk or head and neck. Two prospective randomized surgical trials are now being conducted in North America and in Europe. Until the results of these trials are available, physicians are encouraged to enter patients into these ongoing clinical trials or consider ELND in selected patients where the benefit-risk ratio justifies it. Factors to be considered in this decision include intermediate tumor thickness (ie, 1 to 4 mm thickness), anatomic site, histology (ulceration and growth pattern), and the risk of the operation in individual patient settings.