Evolution of sentinel lymph node biopsy for melanoma at a National Cancer Institute-designated cancer center

Sentinel lymph node biopsy (SLNB) has rapidly evolved into the standard of care for clinically node-negative melanoma. Since adopting sentinel lymph node (SLN) technology in 1993, we have periodically reviewed our institution's results and made several modifications.

From January 1993 to December 1998, 182 patients with clinically node-negative primary cutaneous melanoma underwent SLNB. Charts were retrospectively reviewed and assessed for the technique for the identification of the SLN, the pathologic analysis, and the use of intraoperative frozen section.

The accuracy of SLN identification improved from 91% to 100% with the combination of isosulfan blue dye and radiolabeled colloid over isosulfan blue dye alone. Routine versus selective lymphoscintigraphy identified 7 in-transit SLNs and increased detection of dual nodal basin drainage (15%-27%). Identification of micrometastases in the SLN increased from 14% to 24% after a modification of pathologic evaluation. The positive SLN was the only involved node in most patients (80%). Intraoperative frozen section had a sensitivity of 58% and was of benefit in only 13 of 124 patients (10%).

Several modifications to the identification of the SLNs and the detection of metastatic melanoma have improved our outcome with SLNB. A careful, periodic review of results to identify areas for improvement at each institution is crucial to the success of SLNB for melanoma.