Clinical predictors of malignant pigmented lesions. A comparison of the Glasgow seven-point checklist and the American Cancer Society's ABCDs of pigmented lesions

Abstract

Reducing morbidity and mortality from malignant melanoma is the greatest challenge facing dermatology today. We present a comparison of the Glasgow seven-point checklist and the American Cancer Society's ABCDs of pigmented lesions for detecting early melanomas. Logistic regression analysis showed that the Glasgow checklist (N = 205 lesions) contained two significant variables (irregular outline, P = .001, relative odds = 10.9; diameter greater than 1 cm, P = .005, relative odds = 6.7) for differentiating benign from malignant pigmented lesions whereas a three-point version of the ABCDs (N = 192 lesions) had three significant variables (irregular outline, P = .001, relative odds = 9.3; diameter greater than 6 mm, P = .008, relative odds = 5.5; variegation, P = .05, relative odds = 3.7). All six melanomas scored 3 out of 3 on the ABCD scale for a sensitivity of 1.00 and specificity of 0.98 at a threshold of 3 out of 3. Patients rarely sought dermatologic consultation because of these predictors but often sought help for nonsignificant reasons such as inflammation (P = .93), color change (P = .84), itch (P = .72), and increasing size (P = .38). The simpler three-point scale at a threshold of two had equal specificity (0.88 versus 0.94) and better sensitivity (0.73 versus 0.44) than the Glasgow seven-point checklist at the recommended threshold of three out of seven. We therefore recommend that the American public be better educated about the ABCDs to help increase self-referral so that early melanomas can be found and eradicated.