BackgroundIn sentinel lymph node (SLN)-positive melanoma, two randomized trials demonstrated equivalent melanoma-specific survival with nodal surveillance versus completion lymph node dissection (CLND). Patients with microsatellites, extranodal extension (ENE) in the SLN, or >3 positive SLN constitute a high-risk group largely excluded from the randomized trials, for whom appropriate management remains unknown.MethodsSLN-positive patients with any of the three high-risk features were identified from an international cohort. CLND patients were matched 1:1 to surveillance patients using propensity scores. Risk of any-site recurrence, SLN-basin only recurrence, and melanoma-specific mortality were compared.ResultsAmong 1,154 SLN-positive patients, 166 had ENE, microsatellites, and/or >3 positive SLN. At 18.5 months median follow-up, 49% recurred (versus 26% in patients without high-risk features, pConclusionSLN-positive patients with microsatellites, ENE, or >3 positive SLN constitute a high-risk group with a two-fold greater recurrence risk. For those managed with nodal surveillance, SLN-basin recurrences were more frequent, but all-site recurrence and melanoma-specific mortality were comparable to patients treated with CLND. Most recurrences were outside the SLN-basin, supporting use of nodal surveillance for SLN-positive patients with microsatellites, ENE, and/or >3 positive SLN.