Impact ofin vivoreflectance confocal microscopy on the number needed to treat melanoma in doubtful lesions

Abstract

Background The number needed to treat ratio is an effective method for measuring accuracy in melanoma detection. Dermoscopy reduces the number of false positives and subsequently unnecessary excisions. In vivo confocal microscopy is a non-invasive technique which allows the examination of the skin with cellular resolution. Objectives To assess the impact of RCM analysis on the number of equivocal lesions, assumed to be melanocytic, excised for every melanoma. Methods Consecutive patients (n=343) presenting with doubtful lesions, were considered for enrolment. The lesions were analysed by dermoscopy and RCM and histopathological assessment was considered the reference standard. The main outcome was the number needed to treat, calculated as the proportion of equivocal lesions, excised for every melanoma. Results Dermoscopy alone obtained a hypothetical NNT of 3.73, the combination of dermoscopy and RCM identified 264 equivocal lesions that qualified for excision, 92 of which were confirmed to be a melanoma; resulting in a NNT of 2.87; whereas the analysis of RCM images classified as melanoma 103 lesions with a consequent NNT of 1.12; the difference in the reduction of this ratio was statistically significant (p< 0.0001) between the three groups. There was no significant improvement in sensitivity when comparing the combination of dermoscopy and RCM and RCM alone (94.56% vs. 97.82%; p = 0.043). However, the differences between specificities were statistically significant (p <0.000001), favouring RCM alone. Conclusion The addition of RCM analysis to dermoscopy reduces unnecessary excisions with a high diagnostic accuracy and could be a means for reducing the economic impact associated with the management of skin cancer.

Diagnosis and treatment of melanoma. European consensus-based interdisciplinary guideline – Update 2016

“…Reflectance confocal microscopy increases specificity in equivocal dermoscopic melanocytic lesions in two prospective studies [62]. This technology allows the diagnosis of subclinical lesions as amelanotic melanoma or better distinguishes the limits of the tumour [62], but has recently not been approved by NICE for routine use.…”

False-Negative Cases on Confocal Microscopy Examination: A Retrospective Evaluation and Critical Reappraisal

“…Recent longitudinal prospective studies demonstrated that the systematic application of RCM as a second-level examination in skin oncology influences the lesion outcome in two thirds of cases, improving diagnostic accuracy [8,9]. Although in these studies few false-negative results were found, the risk to miss confocal featureless melanomas should be considered.…”

Automated Delineation of Dermal–Epidermal Junction in Reflectance Confocal Microscopy Image Stacks of Human Skin

“…Basal cell carcinomas have been diagnosed in vivo with 92−100% sensitivity and 97−85% specificity and melanomas with 92−88% sensitivity and 70−84% specificity (Guitera et al, 2012; Nori et al, 2004). Initial implementation in academic clinical settings (Alarcon et al, 2013; Pellacani et al, 2014) showed that RCM imaging combined with dermoscopy, reduced the number of unnecessary biopsies and thus also the economic burden associated with skin cancer management. This success has been achieved by a small cohort of “early adopter” clinicians, who, through working with the technology and performing the clinical studies, have become experts in reading RCM images.…”