Sentinel lymph node biopsy is prognostic but not therapeutic for thick melanoma

Background Sentinel lymph node biopsy (SNB) as a staging and therapeutic procedure in melanomas 1–4 mm in thickness has been investigated extensively, however, the clinical value of SNB in thick melanomas is poorly understood. Methods Patients undergoing operation for clinically node-negative melanoma >4 mm in depth between 2003 and 2010 were identified in the Surveillance Epidemiology and End Results registry. Two groups were constructed: one with a wide excision with SNB and the other with wide excision alone. Results A total of 4,571 patients with clinically node-negative, thick melanoma were identified. The median age was 71 years, 96.9% were white, and 64.3% were male. SNB was performed in 2,746 (60.1%) and was positive in 32.2%. Univariate analysis demonstrated SNB was associated with younger age (64 vs 75 years; P