Sentinel lymph node dissection in patients with malignant melanoma. Diagnostic and therapeutic standards

INTRODUCTION: In patients with cutaneous malignant melanoma, the sentinel lymph node (SLN) reflects the histopathological features of the lymphatic basin with high accuracy. MATERIAL AND METHODS: Three hundred eighty-one melanoma patients at the Hornheide clinic with an overall follow-up of 36 months (November 1998 to October 2001) underwent sentinel lymph node dissection (SLND). RESULTS: The SLNs were successfully found in 93% of truncal melanoma ( n=136), 97% of melanoma of the extremities ( n=184), and 86% of melanoma of the head and neck region ( n=61). Of truncal midline melanomas, 84% ( n=43) showed two or more regional basins, in contrast to 18% of nonmidline melanoma ( n=93). Histopathological analysis revealed occult nodal disease in 25% of all patients. Completion lymphadenectomy revealed residual nodal disease in 8% of all patients with low risk melanoma with a tumor thickness of 0-1.5 mm (two of 26 patients with positive SLN) and in 11% of all patients with high risk melanoma with tumor thickness above 1.5 mm (eight of 70 patients with positive SLN). Tumor relapse was noted in 5% of negative SLN patients and 14% of positive SLN patients. The results of the method were false negative in 2% with a sensitivity of 98%. CONCLUSION: Sentinel lymph node dissection is a reliable and accurate method of staging regional lymph nodes for all primary tumor sites. It can localize occult metastases in unexpected lymphatic basins and provides critical indications for completion lymphadenectomy. It represents an essential method of establishing stratification criteria for future adjuvant trials. Further long-term follow-up is needed to investigate its prognostic relevance to recurrence and overall survival.