Sentinel lymph node status is the most important prognostic factor for thick (≥ 4 mm) melanomas

Abstract

The value of the status of the sentinel lymph node (SLN) in patients with thick melanomas (Breslow thickness > or = 4 mm) is controversial. Using Kaplan-Meier estimates and Cox regression models, we studied 152 patients with primary melanomas > or = 4 mm thickness who underwent sentinel lymph node excision (SLNE) at the university hospitals of Hannover and Göttingen, Germany, between 1998 and 2006. The median tumor thickness was 5.2 (4-18) mm; 58.5% of primary melanomas were ulcerated. Micrometastasis to a SLN was found in 48.7%. The patients with positive SLNs were significantly younger than those with negative SLN (p = 0.01). Of the complete lymph node dissections, 32% contained positive non-SLN. The estimated 5 year recurrence-free survival was 42.5 +/- 5% (+/- standard error) (26.3 +/- 6.6% after positive SLNE, 58.7 +/- 7.1% after negative SLNE). The 5 year overall survival rate was 53.2 +/- 5.4% (37.5 +/- 8.1% after positive SLNE, 67.6 +/- 6.7% after negative SLNE). By multivariate analysis, the SLN was a highly significant predictor for overall survival (p = 0.007, relative risk 2.3, 95%, confidence interval 1.2-4.2). The overall survival was significantly associated with penetration of nodal metastases into the SLN > 0.3 mm (p = 0.001). Other parameters such as tumor thickness, ulceration, age and sex were not significant. In the subgroup of patients with negative SLN, neither tumor thickness nor ulceration was significant. The status of the SLN represents the most important prognostic parameter in patients with thick melanomas, whereas other parameters such as tumor thickness and ulceration loose their prognostic value.