A study of the value of the seven-point checklist in distinguishing benign pigmented lesions from melanoma

A seven-point scoring system has been adopted by the Cancer Research Campaign to help non-dermatologists recognize melanoma (MM). Its value is reviewed in the light of increasing referrals of pigmented lesions. One-hundred and ninety-five patients (M:F, 43:152; mean age=43 years, s.d. = 19) were asked whether their lesions possessed the seven points before diagnosis. The dermatologist assessed the signs. Six patients were unable to comply and some had multiple lesions; thus, 216 lesions were fully assessed by patient and dermatologist, and six by the dermatologist alone. Histology was obtained where appropriate. There were eight MMs, 95 naevi, 80 seborrhoeic warts, three dysplastic naevi, and 36 other lesions. Seven of the eight MMs were diagnosed clinically; the other was biopsied because of suspicious features and was a nodular MM. Four lesions suspected to be MMs proved benign. The predictive value (PV) of a clinical diagnosis of MM was 64% and of non-MM was 99%. Using accepted cutpoints for the seven-point system (refer if score 3) patients' scores gave a PV for MM of 7% and for non-MM of 99%. Two MMs scored less than three. Dermatologists' scores gave a PV for MM of 8% and for non-MM of 99%. One MM scored 3. Univariate analyses showed that enlargement (P<0.05), dermatologists' assessments of an irregular margin (P <0.001), size (P<0.05) and pigmentary irregularity (P<0.05), and patients' assessments of size (P<0.05) were statistically significant. Five patients with MM did not recognize the irregular margin. After stepwise logistic regression analysis of the dermatologists' assessments, only irregularity of the margin remained significant. This single sign gave a PV for MM of 13% and for non-MM of 100%. No MMs were missed. Fifty-five (26%) of 214 non-MM lesions had an irregular margin. No useful discrimination was obtained from the patients’assessments. We conclude that if these results are confirmed then considerable emphasis should be placed on educating the public to recognize the single feature of irregularity of the margin in order to improve the early detection of melanoma.