Seven-point checklist for dermatoscopy: performance during 10 years of prospective surveillance of patients at increased melanoma risk

Abstract

Background: The retrospectively developed 7-point checklist is one of the most applicable dermatoscopic algorithms for clinical use. However, until today no prospective data on the diagnostic performance of this algorithm were reported.

Objective: Our aim was to assess the sensitivity, specificity, and diagnostic accuracy of the 7-point checklist in the setting of a prospective long-term study.

Methods: Patients at increased melanoma risk (n = 688) were screened at regular intervals by naked-eye examination, the dermatoscopic 7-point checklist, and digital dermatoscopy follow-up (10-year study interval).

Results: We detected 127 melanomas including 50 melanomas in situ. The mean Breslow thickness of invasive melanomas was 0.57 mm. A total of 79 melanomas displayed the 7-point checklist melanoma threshold of 3 or more points (62% sensitivity, compared with 78%-95% in retrospective settings). In all, 48 melanomas scored fewer than 3 points and were excised because of complementary information (eg, lesional history, dynamic changes detected by digital dermatoscopy). The specificity of the 7-point checklist was 97% (compared with 65%-87% in retrospective settings). Regression patterns, atypical vascular patterns, and radial streaming were associated with the highest relative risk for melanoma (odds ratio 3.26, 95% confidence interval 2.05-5.16; odds ratio 3.04, 95% confidence interval 1.70-5.46; odds ratio 2.91, 95% confidence interval 1.64-5.15; P < .0003, respectively). Melanomas thicker than 0.5 mm exhibited significantly more regression patterns and atypical vascular patterns (P < .02). The malignant versus benign ratio for all excised lesions was 1:8.6 (127 melanomas, 1092 nonmelanomas).

Limitations: Calculation of the specificity was a limitation. True negative lesions were defined by a score less than 3 points and either the histopathological diagnosis of nonmelanoma or the absence of dynamic changes during digital dermatoscopy follow-up (nonexcised, nonsuspicious, no change).

Conclusions: The 7-point checklist for dermatoscopy was less sensitive but highly specific in this prospective clinical setting. Complementary information clearly increased the sensitivity. Regression patterns or radial streaming in nevi of patients at high risk should raise a higher melanoma suspicion than might be concluded from retrospective studies.