Nevus counting as a risk factor for melanoma: comparison of self-count with count by physician.

Abstract

The number of total body nevi is a major risk marker for malignant melanoma. No previous study has evaluated the accuracy of whole body large nevus (> or = 5 mm) self-counts. Our purpose was to evaluate the accuracy of large nevus self-counts by sex, age, educational level, body site, family history of skin cancer, and nevus characteristics. Self-counting of large nevi by 125 patients was compared with physician counting, with attention to nevus characteristics. Overall, 79% of the self-counts agreed to within +/- 3 nevi of the physician's count. Analysis of variance revealed that the presence of nonpigmented or flat nevi significantly increased the chance of subject undercount, as did male sex. Self-counts of large nevi are comparable to physician's counts and may be useful for melanoma screening.