Recurrence of Melanoma After a Negative Sentinel Node Biopsy: Predictors and Impact of Recurrence Site on Survival

Background. Factors that predict melanoma recurrence after a negative sentinel lymph node biopsy (SLNB) are not well-defined. We evaluated melanoma recurrence patterns, factors prognostic for recurrence, and the impact of recurrence on outcomes after a negative SLNB. Methods. The Sentinel Lymph Node Working Group database was evaluated from 1996 to 2016 for negative SLNB melanoma patients. Clinicopathologic characteristics were correlated with recurrence, overall survival (OS), and melanoma-specific survival (MSS). Results. Median follow-up was 32.1months. Recurrences developed in 558 of 5351 negative SLN patients (10.4%). First-site of recurrence included a local or in-transit recurrence (LITR) in 221 cases (4.1%), nodal recurrence (NR) in 109 cases (2%), and distant recurrence (DR) in 220 cases (4.1%). On multivariable analysis, age, thickness, head/neck or lower extremity primary, and microsatellitosis significantly predicted for an LITR as first-site. Having an LITR as first-site significantly predicted for a subsequent NR and DR, and significantly predicted for worse OS and MSS. Furthermore, thickness and head/neck or lower extremity primary significantly predicted for an NR as first-site, while a prior LITR significantly predicted for a subsequent NR. Factors significantly predictive for a DR included thickness, head/neck or trunk primary, ulceration, and lymphovascular invasion. Patients with any type of locoregional recurrence were at higher risk for a DR. Conclusions.Recurrences occur in 10.4% of negative SLN patients, with LITR and DR being the most common types. Importantly, having an LITR significantly predicts for a subsequent NR and DR, and is prognostic for worse survival after a negative SLNB.