Risks and benefits of sequential imaging of melanocytic skin lesions in patients with multiple atypical nevi

Abstract

Objective: To evaluate the utility of sequential imaging of melanocytic skin lesions.

Design: With the use of a computerized test environment, digital images of 80 melanocytic skin lesions (including 10 early melanomas) were presented to 24 dermatologists with different levels of experience in 3 sessions. The 3 sessions were designed to simulate the decision-making process (1) without the possibility of follow-up, (2) with the possibility of follow-up, and (3) after presentation of follow-up images.

Main outcome measures: Diagnostic performance in terms of sensitivity, specificity, accuracy, treatment threshold, and utility.

Results: The possibility of follow-up increased the treatment threshold in all groups of dermatologists compared with decision making without the possibility of follow-up. The increase of the treatment threshold was accompanied by a loss of sensitivity and a gain in specificity. The overall diagnostic accuracy remained unchanged. After presentation of follow-up images, the diagnostic accuracy improved significantly. The sensitivity improved for all readers, but the specificity improved only for the most experienced readers. The utility of sequential imaging depended on the compliance of patients with follow-up. Under the assumption that all patients are compliant with follow-up, the utility of sequential imaging was superior to decision making without follow-up over a broad range of benefit-risk ratios.

Conclusions: Sequential imaging of melanocytic skin lesions is a useful procedure for patients with multiple atypical nevi. Uncritical use of sequential imaging cannot be recommended, because the utility of this technique depends on the experience in the interpretation of follow-up images and on the patient's compliance with follow-up.