Management of the regional lymph nodes in patients with cutaneous malignant melanoma.

One of the most difficult decisions in the management of patients with melanoma remains whether or not to dissect electively the regional lymph nodes of patients with high risk primary tumors. There is abundant evidence that a proportion of such patients will eventually develop nodal metastases and that the probability of metastasis increases with increasing tumor thickness and depth of invasion. If elective node dissection is performed on all patients with high risk primaries, most patients (who have no tumor in the nodes) will be subjected to a potentially morbid operation from which they can achieve no benefit. On the other hand, a "wait and see" policy accepts that a minority of patients will go on to develop nodal metastases and that if definitive therapy is delayed until metastases are detected clinically their likelihood of survival is much reduced. We describe a new technique of dye-directed selective lymphadenectomy that allows accurate and objective identification of individual patients who have subclinical metastases, the individuals who a priori are most likely to benefit from lymphadenectomy. We also discuss new approaches to the assessment of prognosis after lymphadenectomy for node-spread melanoma, a group of patients in whom the prognosis is not uniformly bad. We end with a consideration of quality assurance aspects of the pathological evaluation of lymphadenectomy specimens.