PURPOSE Circulating tumor DNA (ctDNA) has emerged as a noninvasive biomarker for minimal residual disease (MRD) detection in many solid tumors. However, the role of ctDNA in MRD monitoring for melanoma remains unexplored. In this retrospective study, we aim to assess the sensitivity of a commercially available, tumor-informed, exome-based, ctDNA assay to detect recurrence or relapse of melanoma. METHODS Fifty-six patients with a history of stage II to IV melanoma with no evidence of disease and a seronegative (0 MTM/mL) ctDNA result that preceded histologic or radiologic confirmation of melanoma recurrence were identified. The overall sensitivity of ctDNA detection at recurrence or relapse was evaluated and further stratified based on anatomic sites of relapse. RESULTS The ctDNA assay demonstrated an overall sensitivity of 53.6%. The odds of detecting ctDNA at relapse or recurrence were significant among patients with lymph node metastases (odds ratios ORs, 12.0 95% CI, 2.40 to 60.05; P = .001) and patients with multiple anatomic sites (2+) of metastases (OR, 9.52 95% CI, 1.10 to 82.44; P = .027). Sensitivity for ctDNA detection of recurrence was 33.3% in the brain ( P = .248), 37.5% in skin or muscle ( P = .317), 61.5% in lung metastases ( P = .405), 75% in bone ( P = .625), 87.5% in liver was ( P = .034), and 87.5% in lymph node metastases ( P = .003). CONCLUSION ctDNA monitoring shows potential for detecting relapse in patients with melanoma. The location of melanoma recurrence or relapse may affect shedding of ctDNA and its detection. Larger studies are needed to refine the role of ctDNA in recurrence detection and to improve its diagnostic performance to optimize oncologic surveillance.
Steimle et al. (Thu,) studied this question.