Agreement between self-assessment of melanocytic nevi by patients and dermatologic examination

The number of melanocytic nevi is the strongest risk factor for cutaneous m elanoma. As pigmented skin lesions are visible to everybody, the question h as been raised about whether people can identify themselves as being at ris k for melanoma through self-counting of moles. In 1991, a total of 513 cent ral European melanoma patients and 498 controls were asked to count the tot al number of nevi and the number of atypical nevi on the whole body. Whole- body examination by dermatologists followed. Agreement was assessed on cate gorized nevus counts by means of ordinal kappa values and log-linear modeli ng. Study subjects significantly underestimated the total number of melanoc ytic nevi (p < 0.0001), Chance-corrected overall agreement was rather poor (kappa = 0.14), and the ability to detect many existing nevi was low. Agree ment was higher for atypical melanocytic nevi counts (kappa = 0.37), and th e sensitivity to detect more than one atypical nevus was 0.48. Self-assessm ent of the number of melanocytic nevi was difficult to perform accurately, and people severely underestimated the actual number. Despite these results , people should be encouraged to perform regular skin self-examination for early detection of melanoma.