Objective: To determine the optimal approach of selective sentinel lymph node (SLN) dissection in primary malignant melanoma.
Design: Consecutive 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 biopsy site to mark the SLN. Isosulfan blue (Lymphazurin, Hirsch Industries Inc, Richmond, Va) was injected at the primary biopsy site immediately before the surgical procedure.
Setting: Teaching hospital tertiary care referral center.
Main outcome measures: Successful identification of SLNs being defined as positive for microscopic metastatic melanoma by blue dye staining, radioisotope uptake, or both.
Results: Selective 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 the 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 nodes. No notable complications were encountered. Five recurrent cases from patients with SLNs without microscopic metastatic melanoma (3.8%) and 2 from patients with SLNs with microscopic metastatic melanoma (6%) were found during a median follow-up period of 463 days. A second primary melanoma developed in 2 patients; neither had no local recurrence.
Conclusions: Sequential combination of preoperative lymphoscintigraphy and intraoperative mapping is a reliable way to identify regional SLN. 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.