Adding dermatoscopy to naked eye examination of equivocal melanocytic skin lesions: effect on intention to excise by general dermatologists

Abstract

Background: According to the literature, dermatoscopy can improve diagnostic accuracy for melanoma. However, a weak point of the studies in the literature is that most were carried out in a 'privileged' setting of dermatologists who are expert in dermato-oncology, and who work in departments specializing in screening pigmented lesions. This study was set up to specifically evaluate whether the use of dermatoscopy by general dermatologists would also improve accuracy.

Aim: To analyse the effect on intention to excise lesions (intervention yes/no) of adding either dermatoscopy (20 years after the advent of the method) or detailed lesion classification (melanoma yes/no) to clinical examination by the naked eye. More specifically, we evaluated whether the current practice of general dermatologists using dermatoscopy improves the sensitivity and specificity values, and thus the diagnostic accuracy.

Methods: Eight general dermatologists examined separately clinical images and combined (clinical and dermatoscopic) images of 200 melanocytic lesions that had been excised (64 melanomas and 136 melanocytic naevi).

Results: Focusing on intention to excise (intervention yes/no), addition of dermatoscopy to naked eye examination resulted in an increase in sensitivity for all observers (average gain +4.5%) but an overall nonsignificant reduction in specificity (-4.5%, P=0.10). Diagnostic accuracy, which increased when examination was focused on melanoma (yes/no) classification (+4.1%, P<0.05) remained unchanged (-1.62%; P=0.36).

Conclusions: The effect of adding dermatoscopy to naked eye examination of melanocytic lesions on 'general dermatologists' changes according to the aim of the examination. Dealing with the intention to excise, the increase of sensitivity associated with dermatoscopy (lower risk of leaving a melanoma unexcised) is obtained at the expense of specificity (higher number of melanocytic naevi excised) without improving overall diagnostic accuracy.