Current status of sentinel lymph node biopsy in patients with melanoma

The sentinel node is defined as a lymph node on a direct lymphatic drainage pathway from the primary tumour. The sentinel node biopsy is an invasive and potentially complex diagnostic test that requires considerable skill and experience from nuclear medicine physicians, surgeons and pathologists involved in the process. The procedure provides important staging information. The tumour bearing status of a regional lymph node basin is the most important prognostic factor for patients with a clinically localised melanoma. The recently published final report of the first Multicenter Selective Lymphadenectomy Trial (MSLT-1) shows that sentinel node biopsy with subsequent regional node dissection improves the survival rate in patients with nodal metastases from an intermediate Breslow thickness melanoma (1.23.5 mm). The false negative rate is substantial but can be limited by experience, a meticulous technique and close cooperation of the specialists involved. The surgical procurement of the sentinel nodes is associated with minor morbidity. Sentinel node biopsy is now part of the standard work-up in patients with intermediate thickness melanoma and can be considered in patients with a thinner or thicker melanoma. New lymph node tracers and innovative imaging techniques are likely to improve the sensitivity of the procedure further. Now that the results of MSLT-1 are available, the next question is whether sentinel node-positive patients require further surgery. This issue is addressed by EORTCs Minitub study and the MSLT-2. Until these studies yield results, regional node dissection is recommended for patients with sentinel node metastases.