OPTIMAL SELECTIVE SENTINEL LYMPH-NODE DISSECTION IN PRIMARY MALIGNANT-MELANOMA

Objective: To determine the optimal approach of selective sentinel lym ph node (SLN) dissection in primary malignant melanoma. Design: Consec utive patient study. Prior to selective SLN dissection and wide local excision of the primary melanoma biopsy site, technetium Tc 99m sulfur colloid was injected intradermally around the primary melanoma or bio psy site to mark the SIN. Isosulfan blue (Lymphazurin, Hirsch Industri es Inc, Richmond, Va) was injected at the primary biopsy site immediat ely before the surgical procedure. Setting: Teaching hospital tertiary care referral center. Main Outcome Measures: Successful identificatio n of SLNs being defined as positive for microscopic metastatic melanom a by blue dye staining, radioisotope uptake, or both. Results: Selecti ve intraoperative mapping by gamma probe and visualization of blue dye -stained SLN(s) resulted in a 98% (160/163) successful identification rate. Thirty patients (18.4%) had microscopic metastatic melanoma of t he SLN(s), 22 of whom had subsequently completed lymphadenectomy. In 4 (18.2%) of these 22 patients, further microscopic metastatic disease was found in 1 of 8 nodes, 1 of 8 nodes, 1 of 28 nodes, and 1 of 9 nod es. No notable complications were encountered. Five recurrent cases fr om patients with SLNs without microscopic metastatic melanoma (3.8%) a nd 2 from patients with SLNs with microscopic metastatic melanoma (6%) were found during a median follow-up period of 463 days. A second pri mary melanoma developed in 2 patients; neither had no local recurrence . Conclusions: Sequential combination of preoperative lymphoscintigrap hy and intraoperative mapping is a reliable way to identify regional S LN. The frequency of microscopic metastatic melanoma of the SLN(s) is 18.4%. Gamma-probe-guided resection minimizes the extent of lymph node dissection. Further follow-up is needed to assess the outcome of this group of patients for regional and systemic recurrences.