Reliability of sentinel lymph node biopsy for staging melanoma

Background: The aim of this study was to evaluate the reliability of sentinel lymph node biopsy for staging melanoma. Methods: Two hundred consecutive patients with a cutaneous melanoma of at least 1.0 mm Breslow thickness, without palpable regional lymph nodes, were included from 1993 in a prospective cohort study in a single tertiary care hospital. One day after lymphoscintigraphy, sentinel node biopsy was performed, guided by a gamma probe and patent blue dye. Lymph node dissection was performed only if metastasis was found in a sentinel node. Median follow-up was 32 (range 3-61) months. No patient was lost to follow-up. Results: A sentinel node was removed in 199 of 200 patients (mean 2.2 nodes per patient). Forty-eight patients (24 per cent) had metastasis in a sentinel node. Fifteen patients developed recurrence after removal of a tumour-negative sentinel node; six relapsed in the previously mapped basin (false-negative rate 11 per cent (six of 54)). The overall survival at 3 years was 93 per cent if the sentinel node was negative and 67 per cent if it was positive. Sentinel node status and Breslow thickness were strong predictors of recurrence and survival. Minor complications were seen in 18 patients. Conclusion: The sentinel node status was a strong prognostic factor, even with a false-negative rate of 11 per cent.