J Bejar1, E Sabo, I Misselevich, S Eldar, J H Boss. 1. Department of Pathology, Bnai-Zion Medical Center and Bruce Rapapport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Abstract
BACKGROUND: Efficient tamoxifen treatment of breast cancer patients depends on the degree to which pathologists are consistently able to use the so-called "modified quickscore" method to differentiate between negative and low-grade positive scores based on the current four-grade scale of the estrogen receptor (ER) status of the tumors. OBJECTIVE: To quantitatively test pathologists' ability to adequately render correct readings of the ER status of breast tumors. METHODS: The ER status of breast carcinomas was estimated by two pathologists and measured by computer-supported analysis in sections stained with ER antibody by the immunoperoxidase technique. Levels of agreement between the examiners' semiquantification and histomorphometrically gauged measurements were compared statistically. RESULTS: The kappa coefficients were 0.28 on a case-by-case collation of the grades of nuclear staining, 0.52 on applying binary categories of positively versus negatively stained cell nuclei, and 0.89 using binary categories with a weighted score of 1.2 to separate ER-negative from ER-positive breast carcinomas. CONCLUSIONS: The findings suggest that an optimum rating system is achieved by assigning tumors with a weighted score of 1.2 or less to the ER-negative and those with a weighted score of 1.3 or more to the ER-positive category of breast carcinomas.
BACKGROUND: Efficient tamoxifen treatment of breast cancerpatients depends on the degree to which pathologists are consistently able to use the so-called "modified quickscore" method to differentiate between negative and low-grade positive scores based on the current four-grade scale of the estrogen receptor (ER) status of the tumors. OBJECTIVE: To quantitatively test pathologists' ability to adequately render correct readings of the ER status of breast tumors. METHODS: The ER status of breast carcinomas was estimated by two pathologists and measured by computer-supported analysis in sections stained with ER antibody by the immunoperoxidase technique. Levels of agreement between the examiners' semiquantification and histomorphometrically gauged measurements were compared statistically. RESULTS: The kappa coefficients were 0.28 on a case-by-case collation of the grades of nuclear staining, 0.52 on applying binary categories of positively versus negatively stained cell nuclei, and 0.89 using binary categories with a weighted score of 1.2 to separate ER-negative from ER-positive breast carcinomas. CONCLUSIONS: The findings suggest that an optimum rating system is achieved by assigning tumors with a weighted score of 1.2 or less to the ER-negative and those with a weighted score of 1.3 or more to the ER-positive category of breast carcinomas.