THE IDENTIFICATION AND MAPPING OF MELANOMA REGIONAL NODAL METASTASES - MINIMALLY INVASIVE SURGERY FOR THE DIAGNOSIS OF NODAL METASTASES

The most controversial part of melanoma surgical care involves the rol e of elective lymph node dissection (ELND). Whereas proponents cite re trospective studies demonstrating the ability to control regional meta stases and more accurate staging, opponents cite the unnecessary morbi dity of a complete node dissection for the majority of patients. The t echnology of sentinel node mapping and selective lymphadenectomy, defi ned as the identification and removal of the first node into which the primary melanoma drains, may revolutionize melanoma care. If the sent inel node is negative, then theoretically the remainder of the nodes s hould also be negative (no ''skip'' metastases), and a complete lympha denectomy would not be required to control occult nodal disease. The l ocation of the sentinel node may be variable in the lymphatic basin. I deally, the surgeon needs a map of the position of the sentinel node i n reference to the other nodes in the basin in order to do the procedu re under local anesthesia with small incisions. In this way, patients are subjected to minimal morbidity and the procedure can be performed as an out-patient. Twenty-nine patients with clinically negative nodes and melanomas greater than 0.76 mm in thickness were judged to be can didates for ELND. Preoperative lymphoscintigraphy in two planes was us ed to mark the sentinel node, and the patients were taken to the opera ting room for intraoperative lymphatic mapping and sentinel node biops y followed by complete dissection. Thirty-three per cent of the time, the clinician could not predict the approximate location of the sentin el node within 5 cm, but the lymphoscintigraphy was accurate in the id entification of the location of the sentinel node 100% of the time (P < 0.05). No ''skip'' metastases were identified in these patients, sug gesting that the sentinel node histology can be used as a prognostic f actor to identify a subgroup of the total melanoma population who woul d be candidates for ELND. The use of lymphoscintigraphy is invaluable to the surgeon to identify all basins at risk for metastatic disease a nd the location of the sentinel node(s) in relation to the basin. In t his way, selective lymphadenectomy may be incorporated more widely int o the everyday care of the melanoma patient.