Inter-clinician agreement on the recognition of clinical pigmentary characteristics of patients with cutaneous malignant melanoma. Studies of melanocytic nevi, VI.

The number and type of melanocytic nevi are among the most important known predictors of risk for cutaneous malignant melanoma. In this study, examinations of the skin were conducted by two to four clinicians on 153 patients with newly diagnosed melanoma, and the agreement among clinicians was quantified regarding number of nevi and freckling. The index of agreement (calculated as the intra-class correlation coefficient) was 59.7% and 69.0% for freckling on the right forearm and on the shoulders, respectively; agreement was above 50% for only one of six pairs of clinicians in examining freckling on the right forearm, while agreement was above 50% for four of the six pairs of clinicians in examination of freckling on the shoulder. For palpable nevi of the arms (used in at least two case-control studies as a predictor of risk), the agreement was 36.1% when computed for three examiners assessing 81 patients. However, for total arm nevi (both palpable and non-palpable), assessed on a subset of 48 patients, the agreement was 88.2%; this and other analyses indicated that the difficulty in achieving a consensus for palpable nevi lay in whether or not lesions were considered to be 'palpable' or 'non-palpable'. Agreement for total number of atypical nevi on the body and total number of all types of nevi were 87.4% and 91.8% respectively. These data suggest that the kinds of lesions on which agreement might be reached are total atypical nevi and total nevi of all types on the arms and on the entire body. Greater difficulty might be found in achieving consistency among investigators and among clinicians in examining individual patients with respect to freckling on the arms and 'palpable' nevi. However, some consistency was achieved even with these latter two clinical features.