New developments in sentinel node staging in melanoma: controversies and alternatives.

PURPOSE OF REVIEW

Melanoma incidence is increasing worldwide. Elective lymph node dissections (ELNDs) could not improve survival. The sentinel node is a targeted approach to occult lymph node metastases. There are controversies regarding the sentinel node procedure for melanoma, with regard to false-negative rates, therapeutic benefit and alternatives, such as ultrasound. The clinical relevance of minimal sentinel node tumor burden is unclear. This review analyzes these issues.

RECENT FINDINGS

Through the pathological work-up of the sentinel node, the sentinel node has become an independent prognostic factor for survival in melanoma. False-negative rates of the sentinel node procedure are generally an underestimation, due to incorrect calculations. A subgroup analysis of the Multicenter Selective Lymphadenectomy Trial (MSLT)-1 seemed to demonstrate a survival benefit, but is criticized for a number of reasons. Potentially, a subgroup of sentinel node-positive patients is prognostically false-positive, with dormant metastases, which might not become viable disease.

SUMMARY

Sentinel node tumor burden is an extra dimension to predict prognosis, although we have not yet identified the correct group to undergo a completion lymph node dissection. The MSLT-2 and MINITUB studies are analyzing this issue. The EORTC recommends the Rotterdam criteria as the most reproducible and accurate measure of sentinel node tumor burden. Ultrasound-guided fine needle aspiration cytology is emerging as a potential cost-effective alternative.