Background: Sentinel lymph node (SLN) biopsy is advocated as the standard of care for patients with primary melanoma. It is a procedure with few side-effects and provides valuable staging information about the regional lymphatics.
Objectives: To investigate the prognostic value of SLN biopsy and to compare it with that of other known risk factors in primary melanoma.
Methods: One hundred and forty-nine patients with primary melanomas (tumour thickness >1.0 mm) underwent SLN biopsy between May 1998 and April 2004 at our department. This report summarizes the follow-up data of this cohort until October 2004.
Results: SLN biopsies of 49 of 149 patients (33%) revealed micrometastatic disease. Of all clinical and histological criteria, only the clinical type of primary melanoma (11 of 19 patients with acrolentiginous melanomas) and the Clark level were predictive for SLN positivity. Progression was observed in 22 patients (15%). It was significantly associated with ulceration of the primary tumour, tumour thickness, clinical type and localization of the primary tumour, female sex and older age. In contrast, SLN positivity was not significantly associated with a higher risk of progression (eight of 49 SLN-positive vs. 14 of 100 SLN-negative patients; P = 0.807). Twelve of 149 patients (8%) died because of melanoma in the follow-up period. Significant criteria for death were ulceration of the tumour, clinical type and localization of the primary tumour, but not SLN positivity.
Conclusions: A high percentage of positive SLNs was observed in the patients with melanoma in our study (33%). The fractions of patients both with progressive disease and with tumour-related death were not significantly higher in patients with positive SLN than in those with negative SLN. We therefore conclude that the SLN status is not a reliable prognostic factor for progression of melanoma.