IDENTIFICATION OF VERTICAL GROWTH-PHASE IN MALIGNANT-MELANOMA - A STUDY OF INTEROBSERVER AGREEMENT

Ninety-four H&E-stained slides of malignant melanoma were circulated t o 6 pathologists in 2 university departments. For each slide, the grow th phase of the lesion, Breslow thickness, and Clark level were determ ined by each observer. The aims of the study were to evaluate agreemen t between nonspecialist pathologists in identifying the vertical growt h phase in malignant melanoma and to compare agreement for the growth phase with agreement for Breslow thickness and the Clark level. Our re sults show, that although overall agreement for the growth phase is mo derate, agreement between experienced observers is good. In fact agree ment for the growth phase among this group was equal to the agreement for Breslow thickness. Overall agreement for Breslow thickness also wa s good but for the Clark level was only fair. These findings suggest t hat if the predictive value of the vertical growth phase proves to be robust, it will be wed with an acceptable level of accuracy in routine diagnostic practice.