Ultrasound Surveillance in Melanoma Management: Bridging Diagnostic Promise with Real-World Adherence: A Systematic Review and Meta-Analysis.

BACKGROUND: Ultrasound surveillance has become the new standard of care in stage III melanoma after the 2017 Multicenter Selective Lymphadenectomy Trial II (MSLT-II) demonstrated non-inferior 3-year survival compared with complete lymph node dissection.

OBJECTIVE: We aimed to quantify diagnostic performance and adherence rates of ultrasound surveillance for melanoma locoregional metastasis, offering insights into real-world applicability.

METHODS: Conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, we systematically searched the Medline, Embase, Cochrane Library, CINAHL, Scopus, and Web of Science databases from inception until 11 October 2023. All primary studies that reported data on the diagnostic performance or adherence rates to ultrasound surveillance in melanoma were included. R statistical software was used for data synthesis and analysis. Sensitivity and specificity were aggregated across studies using the meta-analytic method for diagnostic tests outlined by Rutter and Gatsonis. Adherence rates were calculated as the ratio of patients fully compliant to planned follow-up to those who were not.

RESULTS: A total of 36 studies including 18,273 patients were analysed, with a mean age of 56.6 years and a male-to-female ratio of 1:1.11. The median follow-up duration and frequency was 36 and 4 months, respectively. The pooled sensitivity of ultrasound examination was 0.879 (95% confidence interval [CI] 0.878-0.879) and specificity was 0.969 (95% CI 0.968-0.970), representing a diagnostic odds ratio of 224.5 (95% CI 223.1-225.9). Ultrasound examination demonstrated a substantial improvement in absolute sensitivity over clinical examination alone, with a number needed to screen (NNS) of 2.95. The overall adherence rate was 77.0% (95% CI 76.0-78.1%), with significantly lower rates in the United States [US] (p <  0.001) and retrospective studies (p <  0.001).

CONCLUSION: Ultrasound is a powerful diagnostic tool for locoregional melanoma metastasis. However, the real applicability to surveillance programmes is limited by low adherence rates, especially in the US. Further studies should seek to address this adherence gap.