The ABCD system of melanoma detection - A spectrophotometric analysis of the asymmetry, border, color, and dimension

BACKGROUND. The ABCD (Asymmetry, Border, Color, and Dimension) criteria rep resent a commonly used clinical guide for the diagnosis of early melanoma. The authors revised these criteria in the light of objective measurements o f the features of pigmented skin lesions obtained by telespectrophotometric analysis (TS) in the visible and near-infrared wavelengths. METHODS. This study involves a consecutive series of 186 patients with 195 cutaneous pigmented lesions (53 melanomas and 142 nonmelanoma lesions). Eac h lesion was subjected to TS in vivo, before surgery. For this purpose, the authors used four spectrophotometric parameters that could be closely rela ted to the four criteria of the ABCD guide, namely, roundness (an estimate of how a lesion contour resembles a circle), smoothness (an indicator of th e regularity of a lesion border), mean reflectance (the ability of a lesion to diffuse or reflect the incident light), and size (the greatest dimensio n of a lesion). RESULTS. When melanomas and nonmelanoma lesions were compared by univariate analysis, all four spectrophotometric parameters considered proved to be s ignificantly different (P = 0.05). Multivariate logistic analysis showed th at mean reflectance in the infrared (P < 0.01) and size (P = 0.03) were par ameters independently associated with melanoma. Melanoma showed lower refle ctance and greater size than benign lesions. CONCLUSIONS. Information provided by TS substantially validates the importa nce of the ABCD clinical guide and suggests that color is the most importan t parameter in discriminating melanoma from nevi. In particular, melanoma a ppears darker than other pigmented lesions. Cancer 1999;85:72-77, (C) 1999 American Cancer Society.