Diagnostic performance and clinical limitations of sentinel lymph node biopsy in head and neck melanoma: a 20-year retrospective cohort study

PURPOSE: Sentinel lymph node biopsy (SLNB) is a standard procedure for nodal staging in cutaneous melanoma. However, its diagnostic performance in the head and neck region remains limited due to complex lymphatic drainage patterns. This study aimed to evaluate the long-term diagnostic accuracy of SLNB in head and neck melanoma and to analyze anatomical and clinical factors associated with false-negative results. METHODS: This retrospective single-center cohort study included patients with cutaneous head and neck melanoma who underwent SLNB between 2002 and 2022. Patients were stratified into two cohorts (2002-2011 and 2012-2022). Detection rates, sensitivity, negative predictive value, and false-negative rates were calculated. Overall survival was analyzed using Kaplan-Meier estimates and compared by log-rank testing. RESULTS: A total of 189 patients were included. Sentinel lymph node detection significantly improved from 78.2% in the earlier cohort to 98.0% in the later cohort (p < 0.0001). Across the combined cohort, SLNB sensitivity was 72.5%, with a false-negative rate of 27.5%. False-negative events predominantly occurred in anatomically complex drainage regions. Sentinel lymph node status was not significantly associated with overall survival (p = 0.627). CONCLUSIONS: Despite substantial improvements in detection rates, SLNB in head and neck melanoma demonstrates clinically relevant limitations in diagnostic sensitivity. The observed false-negative rate highlights a risk of understaging, which may affect eligibility for adjuvant systemic therapies. SLNB findings should therefore be interpreted in the context of anatomical risk patterns and integrated into individualized follow-up strategies. The lack of an association between sentinel lymph node status and overall survival may reflect the impact of modern adjuvant systemic therapies and the distinct biological behavior of head and neck melanoma. However, this finding should be interpreted with caution given the limited sample size. These findings underscore the importance of procedural expertise and risk-adapted surveillance in this anatomically complex region.