Bloom-Richardson grade
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Overview
The Bloom-Richardson grade (BR grade) is a a histologic grade assigned by pathologists to breast cancers. It is the most common type of cancer grade system currently used. It is a semi-quantitative grading method based on three morphologic features of invasive breast cancers. The morphologic features that are used are:
- degree of tumor tubule formation (percentage of cancer composed of tubular structures)
- tumor mitotic activity (rate of cell division)
- nuclear pleomorphism of tumor cells (nuclear grade, change in cell size and uniformity)
Each of these features is assigned a score ranging from 1 to 3. The scores are then added together for a final sum that will range between 3 to 9. This value is then used to grade the tumor as follows :
- 3-5 Grade 1 tumor (well-differentiated).
- 6-7 Grade 2 tumor (moderately-differentiated).
- 8-9 Grade 3 tumor (poorly-differentiated).
References
- Bloom H, Richardson W (1957). "Histological grading and prognosis in breast cancer; a study of 1409 cases of which 359 have been followed for 15 years". Br J Cancer. 11 (3): 359–77. PMID 13499785.