The Bloom–Richardson grading system from 1957 refers to a breast cancer classification system to grade breast cancers, and was the precursor of the present criteria, the modified Bloom–Richardson–Elston grading (BRE) system (also called the Nottingham system.) The cells and tissue structure of the breast cancer are examined histopathologically to determine how aggressive the cancer is. Lower grade tumors, with a good prognosis, can be treated less aggressively, and have a better survival rate. Higher grade tumors are treated more aggressively, and their intrinsically worse survival rate may warrant the adverse effects of more aggressive medications. The references highlight the historical and current criteria; the latter system is judged more reproducible and is the recommended grading method. The breast cancer classification article has further details of current breast cancer grading criteria.
Summary of semiquantitative method for assessing histologic grade in Breast Carcinoma
Tubule formation >75% 1 point 10%-75% 2 point <10% 3 points
Nuclear pleomorphism Small, regular uniform cells 1 point Moderate increase in size and variability 2 points Marked Variation 3 points
Mitotic counts Dependent on microscope field area 1-3 points