The Role of Selective Lymphadenectomy in the Management of Patients with Malignant Melanoma

BACKGROUND: A novel surgical technique based on selective lymphadenectomy was used to stage 132 patients with intermediate and thick cutaneous malignant melanoma. Preoperative and intraoperative lymph node mapping techniques were used to ascertain regional lymph node basins at risk for metastasis, and to identify the first node(s) the afferent lymphatics encounter in the basin, defined as the "sentinel" node(s). It has been shown that the histology of the sentinel node reflects the histology of the rest of the nodal bain, and according to preliminary studies using this technique, the likelihood of bypassing the sentinel node(s) to "higher" level nodes is less than 2%. Epidemiologic studies indicate that the long-term survival of patients with melanomas of intermediate thickness or greater is significantly compromised if regional lymph nodes are involved. Yet, the utility of performing lymph node dissections for the purposes of staging only is controversial, not only because of the morbidity and expense of the procedure, but the lack of proven survival benefit. OBJECTIVE: In the present study, we performed preoperative and intraoperative lymphatic mapping, harvested clinically normal sentinel nodes, and examined them for micrometastasis by light microscopy. Both conventional stains and immunocytochemistry for S-100 protein and HMB-45 antibodies were performed, and only those patients with documented micrometastasis received complete lymph node dissections. RESULTS: The sentinel node(s) was identified in each of the patients. Micrometastatic disease was detected in 31 (23%) of the patients by selective lymphadenectomy, and the sentinel node(s) was the only node involved in 83% of the cases upon subsequent complete nodal dissection. CONCLUSION: Our preliminary results suggest that selective lymphadenectomy following lymphatic mapping is an effective procedure for staging melanoma patients with lesions of intermediate thickness or greater. Our results indicate that sentinel lymph nodes may be successfully identified and harvested in the majority of patients, and that they may be examined for the first evidence of micrometastasis without the need of a complete nodal dissection. Information as to whether micrometastases are present in the sentinel node would be valuable in staging patients, and identifying candidates for complete nodal dissections. We are participating in a National Cancer Institute-sponsored multicenter trial to ascertain whether this surgical approach can impact on the recurrence rate and survival of patients with stage 1 and 2 melanoma.