Sentinel lymph node biopsy in melanoma: final results of MSLT-I

In 1994 an international randomized controlled clinical trial, MSLT-I, opened to study the utility of sentinel lymph node biopsy (SLNB) for patients with clinically localized melanoma. This trial compared outcomes of patients treated with wide local excision (WLE) and SLNB (followed by immediate completion lymph node dissection [CLND] for those with a positive sentinel node [SN]) with outcomes of patients treated with WLE alone and CLND upon the development of clinically apparent disease. In February 2014 the final analysis of long-term outcomes data was published. Importantly, these data showed that the rates of nodal positivity were the same between the two arms of the trial. Although no difference in 10-year melanoma-specific survival was noted between the two arms, this was not entirely surprising as the overall rate of nodal disease within the trial was 20.8%, meaning that 79.2% of patients could not derive a benefit from SLNB. Subset analysis was performed to determine the impact of early intervention for those patients most likely to have a benefit from early detection. This analysis showed that for patients with nodal disease and intermediate-thickness melanoma (defined as 1.2-3.5-mm Breslow depth), early treatment following positive SLNB was associated with improved 10-year distant disease-free survival and improved 10-year melanoma-specific survival.