RESULTS OF COMPLETE LYMPH-NODE DISSECTION IN 83 MELANOMA PATIENTS WITH POSITIVE SENTINEL NODES

Background: The technique of sentinel lymph node (SLN) biopsy for mela noma provides accurate staging information because the histology of th e SLN reflects the histology of the entire basin, particularly when th e SLN is negative. Methods: We combined two mapping techniques, one us ing vital blue dye and the other using radiolymphoscintigraphy with a hand-held gamma Neoprobe, to identify the SLN in 600 consecutive patie nts with stage I-II melanoma. The SLNs were examined using conventiona l histopathology and immunohistochemistry for S-100. Results: Eighty-t hree (13.9%) patients had micrometastatic disease in the SLNs. Thirty percent of patients with primary melanomas greater than 4.0 mm in thic kness had positive SLNs, followed by 48 of 267 (18%) of patients with tumors between 1.5 mm and 4 mm, and 12 of 169 (7%) of those with lesio ns between 1.0 mm and 1.5 mm. No patient with a tumor less than 0.76 m m in thickness had a positive SLN. Sixty-four of the 83 SLN-positive p atients consented to undergo complete lymph node dissection (CLND), an d five of 64 (7.8%) of the CLNDs were positive. All patients with posi tive CLNDs had tumor thicknesses greater than 3.0 mm. Conclusions: The rate of SLN-positive patients increases with increasing thickness of the melanoma. SLN-positive patients with primary lesions less than 1.5 mm in thickness may have disease confined to the SLN, thus rendering higher-level nodes free of disease, and may not require a CLND.