Validation of a Method to Reduce the Number of Sentinel Nodes Removed in Melanoma Patients: A Preliminary Prospective Survey

Abstract

Sir: Sentinel lymph node biopsy1,2 has become a widely accepted method of staging lymph nodes for patients with melanoma. The current literature points out an increasing number of nodes removed for each procedure, leading to a higher human and economic cost for the procedure. The objective of the current study was to show that the number of sentinel lymph nodes removed could be minimized without influencing the reliability of tumor staging. A single-arm prospective study was conducted between January of 2002 and September of 2004. Patients older than 18 years of age with cutaneous melanoma of greater than or equal to 1 mm Breslow thickness and clinically negative regional lymph nodes were eligible after providing informed consent. An intradermal injection of 0.2 ml (10 to 15 MBq) of colloidal particles labeled with technetium-99m was administered. The location of the sentinel lymph node was marked on the skin with a pen. The melanoma was excised. The exact localization of the sentinel lymph node was determined preoperatively using a hand-held gamma counter. The most radioactive node was dissected, as were the nodes with radioactivity greater than 70 percent compared with the hottest node. Once the sentinel lymph node was removed, it was sent immediately to the pathologist. Three cuts from both surfaces were stained with hematoxylin and eosin and examined microscopically for metastatic localization. After they were preserved in formaldehyde, six sections were stained by an immunocytochemical method with anti-protein S100 serum, anti-HMB45, and anti-MelanA antibodies. We analyzed the characteristics of the melanoma, the success rate of the procedure, how many nodes were removed, and how many had micrometastases. Ninety patients were included. Their mean age was 62.8 years (range, 25 to 90 years). The mean tumoral thickness was 2.96 mm (range, 0.3 to 20 mm). The sites of the primary melanoma were the trunk (14 percent), head and neck (14 percent), upper extremities (26 percent), and lower extremities (46 percent). One lymph node basin per patient was mapped. Sentinel nodes were identified in 100 percent of cases. One hundred five sentinel lymph nodes were identified (mean, 1.3 per patient; range, one to three per patient). In 74 percent of patients, only one lymph node was removed; in 22 percent, two sentinel lymph nodes were identified; and in three patients (4 percent), three sentinel lymph nodes were removed. Metastasized melanoma was detected in 19 sentinel lymph nodes from 19 patients (22 percent). All of these patients went on to have a complete dissection of the involved basin, and additional positive nodes were found in only one patient. During the follow-up (mean, 18.8 months; range, 8 to 32 months), one patient with a negative sentinel lymph node had a basin recurrence (2.5 percent), whereas two patients with positive sentinel lymph nodes had distant metastases (18.18 percent). As a preliminary evaluation in this communication, these results were compared with those of two literature studies.3,4 There was no significant difference with respect to the success rate of the procedure, detection of metastatic nodes, or recurrence rate after negative sentinel lymph node biopsy. However, we point out a significant difference with regard to the number of sentinel lymph nodes removed. Alain Danino, M.D., Ph.D. Gabriel Malka Sophie Dalac, M.D. Department of Plastic and Reconstructive Surgery Dijon University Hospital Dijon, France