Micrometastasis of a sentinel lymph node in cutaneous melanoma is a significant prognostic factor for disease-free survival, distant-metastasis-free survival, and overall survival

OBJECTIVE. Sentinel lymph node biopsy (SLNB) has been proposed as a minimally invasive procedure for the histopathologic staging of the regional lymph node basin. The aim of this work was to investigate the prognostic value of detection of micrometastasis by SLNB. METHODS. In the period from January 1996 to March 2000, a sentinel lymph node (SLN) was identified in 283 patients at the Department Dermatology, University of Tuebingen. In the case of 38 patients (13.4%) histopathologic examination led to the detection of micrometastasis in at least one SLN. The median follow-up period was 29 months. RESULTS. Thirty-one of 245 patients (12.7%) suffered a tumor recurrence following a negative SLNB, and 19 of 38 patients (50%) following positive SLNB. In the case of disease-free survival the remaining significant independent prognostic factors of the multivariate analysis were tumor thickness (p=0.011), ulceration (p=0.026), and the detection of micrometastasis in SLNB (p=0.021). With respect to distant-metastasis-free survival the significant independent prognostic factors of the multivariate analysis were tumor thickness (p=0.0022) and the SLNB results (p=0.0068). For overall survival the tumor thickness (p=0.013) and the SLNB results (p=0.034) were significant independent prognostic parameters in the multivariate analysis. CONCLUSION. The study examined patients with melanomas of all tumor thicknesses and SLNB for which the prognostic significance of SLNB was tested. Recurrences were more frequent in patients with a micrometastatic SLN. Patients with a negative SNLB are still at risk for tumor recurrence. The histopathologic result of SLNB is, after tumor thickness, the most significant prognostic factor for disease-free survival, distant-metastasis-free survival, and overall survival.