Effect of Reflectance Confocal Microscopy for Suspect Lesions on Diagnostic Accuracy in Melanoma

Abstract

Previous systematic reviews and meta-analyses have concluded that given data paucity, a comparison of reflectance confocal microscopy (RCM) with dermoscopy is complex. They recommend comparative prospective studies in a real-world setting of suspect lesions. To test the hypothesis that RCM reduces unnecessary lesion excision by more than 30% and identifies all melanoma lesions thicker than 0.5 mm at baseline. This randomized clinical trial included 3165 patients enrolled from 3 dermatology referral centers in Italy between January 2017 and December 2019, with a mean (SD) follow-up of 9.6 (6.9) months (range, 1.9-37.0 months). The consecutive sample of 3165 suspect lesions determined through dermoscopy were eligible for inclusion (10 patients refused). Diagnostic analysis included 3078 patients (48 lost, 39 refused excision). Data were analyzed between April and September 2021. Patients were randomly assigned 1:1 to standard therapeutic care (clinical and dermoscopy evaluation) with or without adjunctive RCM. Information available guided prospective clinical decision-making (excision or follow-up). Hypotheses were defined prior to study initiation. All lesions excised (baseline and follow-up) were registered, including histopathological diagnoses/no change at dermoscopy follow-up (with or without adjunctive RCM). Number needed to excise (total number of excised lesions/number of melanomas) and Breslow thickness of delayed diagnosed melanomas were calculated based on real-life, prospective, clinical decision-making. Among the 3165 participants, 1608 (50.8%) were male, and mean (SD) age was 49.3 (14.9) years. When compared with standard therapeutic care only, adjunctive RCM was associated with a higher positive predictive value (18.9 vs 33.3), lower benign to malignant ratio (3.7:1.0 vs 1.8:1.0), and a number needed to excise reduction of 43.4% (5.3 vs 3.0). All lesions (n = 15) with delayed melanoma diagnoses were thinner than 0.5 mm. This randomized clinical trial shows that adjunctive use of RCM for suspect lesions reduces unnecessary excisions and assures the removal of aggressive melanomas at baseline in a real-life, clinical decision-making application for referral centers with RCM. ClinicalTrials.gov Identifier: NCT04789421.