Background: This analysis was performed to identify prognostic factors that are predictive of sentinel lymph node (SLN) metastasis in melanoma.
Methods: Analysis was performed of a multi-institutional, prospective, randomized trial of SLN biopsy for melanoma. Eligibility criteria included age 18 to 70 years, Breslow thickness of 1.0 mm or more, and clinically negative regional lymph nodes. SLNs were evaluated by serial sectioning and immunohistochemistry for S100. Univariate chi-square and multivariate logistic regression analyses were performed to assess factors predictive of the presence of a positive SLN. Probability values of less than.05 were considered significant.
Results: SLNs were identified in 99.7% of patients. A total of 1058 patients were evaluated; 961 patients had complete data and were included in the statistical analysis. SLNs were positive for tumor in 208 of 961 patients (22%). Breslow thickness, Clark level, ulceration, and patient age were factors that were found to be independently predictive of the presence of SLN metastasis.
Conclusions: Increasing Breslow thickness, Clark level of more than III, the presence of ulceration, and patient age of 60 years or less are the most important independent prognostic factors associated with the finding of positive SLN in patients with melanoma.