V_3_5_8 Bloom-Richardson Grade for Breast Cancer

V.3.5.8 Bloom-Richardson Grade for Breast Cancer

Use these instructions for cases diagnosed on or before 12/31/2013 only.

For cases diagnosed 01/01/2014 forward, see Section V.3.7.4

Beginning with breast cancer cases diagnosed January 1, 1996, the Bloom-Richardson grading system should be used, if available.

Synonyms include: Modified Bloom-Richardson, Scarff-Bloom-Richardson, Nottingham, SBR Grading, BR Grading, Elston-Ellis modification of Bloom-Richardson grading system. This grading scheme is based on three morphologic features as follows:

Degree of tumor tubule formation
Tumor mitotic activity
Nuclear pleomorphism of tumor cells (nuclear grade)

Seven possible scores are condensed into three Bloom-Richardson grades. The three grades then translate into well-differentiated (BR low grade), moderately differentiated (BR intermediate grade) and poorly differentiated (BR high grade).

Tumor Tubule Formation	Score
>75% of tumor cells arranged in tubules	1
>10% and <75%	2
<10%	3
Number of Mitoses (low power scanning (X100), find most mitotically tumor area, proceed to high power (x400))
<10 mitoses in 10 high-power fields	1
>10 and <20 mitoses	2
>20 mitoses per 10 high power fields	3
Nuclear Pleomorphism (nuclear grade)
Cell nuclei are uniform in size and shape, relatively small, have dispersed chromatin patterns, and are without prominent nucleoli	1
Cell nuclei are somewhat pleomorphic, have nucleoli, and are intermediate size	2
Cell nuclei are relatively large, have prominent nucleoli or multiple nucleoli, coarse chromatin patterns, and vary in size and shape	3

To obtain the final Bloom-Richardson (Nottingham) score, add score from tubule formation plus number of mitoses score, plus score from nuclear pleomorphism. The combined score converts to the following BR grade:

Bloom-Richardson (Nottingham) Combined Scores	Differentiation/BR Grade	ICD-O-3 6th Digit
3, 4, 5	Well-differentiated (BR low grade)	1
6, 7	Moderately differentiated (BR intermediate grade)	2
8, 9	Poorly differentiated (BR high grade)	3

There are coding rules and conventions to be used to code breast cancer cases. Use grade or differentiation information from the breast histology in the following priority order:

Bloom-Richardson (Nottingham)scores 3-9 converted to grade (see conversion table below)
Bloom-Richardson grade (low, intermediate, high)
Nuclear grade only
Terminology (well diff, mod diff…)
Histologic grade (grade I, grade ii…)

Caution: In this grading system, the terms low, intermediate, and high are codes 1, 2, and 3 respectively. This is an exception to the usual rule for all other grading systems which code "low", "intermediate", and "high" as 2, 3, and 4 respectively. In the Bloom-Richardson system, if grades 1, 2, and 3 are specified, these should be coded 1, 2, and 3 respectively.

When the only information is a diagnosis of "high grade ductal carcinoma of the breast", with no mention of Bloom-Richardson, use code 4 (Grade 4).

Bloom-Richardson (Nottingham) Scores	Bloom-Richardson Grade	Nuclear Grade	Terminology	Histological Grade	Code
3- 5 points	Low Grade	1/3, 1/2	Well Differentiated	(BR low grade)	1
6, 7 points	Intermediate Grade	2/3	Moderately differentiated	(BR intermediate grade)	2
8, 9 points	High Grade	2/2, 3/3	Poorly Differentiated	(BR high grade)	3

Note: This grading system is coded in a site-specific factor for the applicable CS schema.

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