Prognostic Implications of Primary Site in Cutaneous Head and Neck Melanoma After the Implementation of Sentinel Node Biopsy: A SEER-Based Analysis (2011–2020)

Background: Scalp and neck (SN) melanoma demonstrates the worst prognosis among all cutaneous head and neck melanomas (CHNMs). The objective of this study was to evaluate the melanoma-specific survival (MSS) in SN melanoma compared with other CHNM after the widespread clinical adaptation of sentinel lymph node biopsy in 2011 and asses whether tumor site is associated with distant metastases. Patients and Methods: A retrospective cohort study was carried out using Surveillance, Epidemiology, and End Result (SEER) data from 2011 to 2020, comprising 13,825 CHNM cases. Cox and multinomial logistic regression models were used to estimate adjusted hazard ratios and adjusted odds ratio (aORs). Results: SN melanoma was associated with significantly worse MSS, with 5-year MSS rates of 76.5% versus 82.7%. Multivariable analysis showed SN melanoma had worse MSS (aHR 1.28; 95% confidence interval [CI] 1.16–1.41) and higher odds of presenting with lung metastases (aOR 2.39; 95% CI 1.35–4.25) and multisite metastases (aOR 2.23; 95% CI 1.28–3.88). A limitation of the study was that the SEER database groups SN together despite previous research suggesting that the scalp component contributes to most of the poor prognoses. Conclusions: SN melanoma is associated with worse MSS among all CHNMs despite the routine use of SLNB. SN melanoma also follows a distinct metastatic pattern to solid organs, particularly to the lungs.