Sentinel node biopsy in melanoma: Current controversies addressed.

Sentinel node biopsy (SNB) is the most accurate staging tool for melanoma patients. The procedure is indicated especially for intermediate thickness melanoma (pT2/3). SNB can be of value in thin melanoma (>0.75 mm in thickness), with adverse prognostic factors, and in thick melanomas (pT4), although T4 patients are already at high risk of disease progression. Completion lymph node dissection (CLND) after positive SN yields additional non-sentinel lymph nodes (NSNs) in 20% of cases. Several factors are predictive for NSN positivity, such as primary tumor characteristics and SN tumor burden. The most used and best validated tumor burden parameter is the maximum diameter of the SN metastasis. Others are the microanatomic location of the metastasis in the SN and tumor penetrative depth. These parameters might be used to stratify risk and select patients for either adjuvant treatment trials (diameter >1 mm), or refraining from treatment (minimal SN tumor burden). There is no undisputed evidence for an overall treatment-related benefit for SNB-based management, although benefit has been suggested for a subgroup of node positive patients with intermediate-thickness melanomas. The DeCOG-SLT study failed to demonstrate a survival benefit for CLND after a positive SN. Results of the MSLT-2 and EORTC 1208 (MINITUB) trial, that both assess the role of CLND in SN positive patients have to be awaited. There might be a role for US-FNAC in melanoma staging. New SN visualization techniques can help allow easier identification of SNs in complex areas, shorten operation time and possibly reduce the amount of false-negative SNBs.