INTRALABORATORY VARIATIONS IN THE GRADING OF BREAST-CARCINOMA

Abstract

To assess the reliability of the WHO grading system for [human] breast carcinomas, 6 observers independently graded 158 tumors. Five of the observers had been simultaneously trained in the same institution. The 6th was one of their tutors. There was agreement in the grading of only 23 cases, most of which were either well or poorly differentiated tumors. If the prognosis of breast carcinoma is predicted by the WHO method, it should be restricted to the 2 extreme groups. There is apparently no need to apply the WHO grading method because these groups could be easily distinguished by the overall impression of the examining pathologists.