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The AC Rule for melanoma: A simpler tool for the wider community

2011; Elsevier BV; Volume: 65; Issue: 6 Linguagem: Inglês

10.1016/j.jaad.2011.05.012

1097-6787

Matthew J. Luttrell, Rainer Hofmann‐Wellenhof, Regina Fink‐Puches, H. Peter Soyer,

Melanoma and MAPK Pathways

To the Editor: The AC Rule for melanoma (asymmetry, color variation) was conceived as a simpler tool that laypersons might use to successfully identify a melanoma. It could potentially be used for both clinical (naked eye) and dermatoscopic assessment. We conducted an image-based study using laptop computers in the community. Two groups of volunteers were invited to participate; laypersons and expert dermoscopists. Laypersons (n = 17) were between 18 and 65 years of age and had no professional health care experience. Experts (n = 3) had more than 15 years of professional dermatoscopy experience. Participants were given a one-page information sheet on the AC Rule for melanoma (Fig 1). Clinical images of melanocytic lesions (N = 312) were obtained from the Department of Dermatology at the Medical University of Graz in Austria. The 100 lesions used in each of two PowerPoint slideshows were drawn at random from this image bank. Participants viewed a clinical image, then a dermatoscopic image for each lesion. They scored each image for asymmetry from 0 (no asymmetry) to 10 (marked asymmetry) on a visual analog scale. They then scored each image for color variation from 0 (no color variation) to 10 (marked color variation). Finally, participants made an overall assessment for each image as either “suspicious” or “not suspicious” for melanoma. By design, experiment 1 included 5 melanomas, 5 atypical (dysplastic) nevi, and 90 common nevi. Experiment 2 contained 20 melanomas, 20 atypical nevi, and 60 common nevi. Subjects were unaware of the change in melanoma prevalence. In all other aspects these two experiments were identical and completed by all participants. Tests of statistical significance for sensitivity and specificity were performed by logistic regression to estimate error rate odds ratios and their respective P value. Laypersons used the AC Rule with clinical photographs to achieve a high sensitivity and low specificity for melanoma identification. There was no significant change in the sensitivity (92.9%, 90.6%; P = .45) or specificity (64.1%, 65.7%; P = .97) when the prevalence of melanoma and atypical nevi increased from 5% to 20%. Table I compares the performance of each study group. Laypersons’ sensitivity was significantly higher than experts’ sensitivity in experiment 1 (92.9% vs 86.7%; P = .02), although the difference was not significant in experiment 2 (90.6% vs 88.3%; P = .47) and combined data (91.2% vs 87.6%; P = .24). Laypersons had a significantly lower specificity in both experiments and combined data (64.2% vs 88.1%; P < .001).Table IComparison of group performance with clinical photographs: Means and odds ratios (95% confidence limits) for sensitivity and specificityExperimental error rate (LP vs EX)Laypersons (%)Experts (%)Odds ratio95% confidence limitP valueExperiment 1 Sensitivity92.986.70.490.27, 0.90.02 Specificity64.192.36.703.91, 11.48<.001Experiment 2 Sensitivity90.688.30.790.41, 1.50.47 Specificity65.783.32.611.85, 3.70<.001Combined Sensitivity91.287.60.720.41, 1.25.24 Specificity64.288.14.063, 5.48<.001EX, Experts; LP, laypersons. Open table in a new tab EX, Experts; LP, laypersons. In this study, we have simplified the ABCD criteria1Friedman R.J. Rigel D.S. Kopf A.W. Early detection of malignant melanoma: the role of physician examination and self-examination of the skin.CA Cancer J Clin. 1985; 35: 130-151Crossref PubMed Scopus (681) Google Scholar, 2Rigel D.S. Friedman R.J. Kopf A.W. Polsky D. ABCDE—an evolving concept in the early detection of melanoma.Arch Dermatol. 2005; 141: 1032-1034Crossref PubMed Scopus (148) Google Scholar to make it more accessible to people without a medical background. Laypersons were able to use the AC Rule to achieve a high sensitivity for melanoma detection when viewing clinical photographs. Further study of this tool with the participant’s own pigmented skin lesions is suggested. Limitations of this study include selection bias in the recruitment of participants and the absence of a control group using no specific method or other analytical methods, such as ABCD. We will be undertaking a randomized control trial from a representative population to confirm these positive findings. We are very grateful to all volunteers who participated in this study.