9577 Background: Circulating tumor DNA (ctDNA) is a novel biomarker for detecting molecular residual disease (MRD) and monitoring recurrence risk in melanoma. Personalized, tumor-informed ctDNA assays may enable highly sensitive and specific longitudinal detection of disease burden following curative-intent surgery. Here, we evaluate the prognostic value of whole-genome sequencing (WGS)-based ctDNA detection in patients with resected stage I–IIIB melanoma. Methods: This was a retrospective analy