How is invasive carcinoma of the breast graded?

Updated: May 24, 2018
  • Author: Peter Abdelmessieh, DO, MSc; Chief Editor: Marie Catherine Lee, MD, FACS  more...
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The National Comprehensive Cancer Network [3] recommends using the Nottingham Criteria [4] in grading invasive carcinoma of the breast. [4] Separate scores are given for gland (acinus) formation, nuclear atypica/pleomorphism, and mitosis counts.

Gland (acinus) formation is scored as follows:

  • Score 1: >75% of the whole carcinoma forms acini
  • Score 2: 10-75% of the whole carcinoma forms acini
  • Score 3: <10% of the whole carcinoma forms acini

Nuclear atypia/pleomorphism is scored as follows:

  • Score 1: Nuclei only slightly larger than benign breast epithelium (<1.5 × normal area); minor variation in size, shape, and chromatin pattern
  • Score 2: Nuclei distinctly enlarged (1.5–2 × normal area), often vesicular, nucleoli visible; may be distinctly variable in size and shape but not always
  • Score 3: Markedly enlarged vesicular nuclei (>2 × normal area), nucleoli often prominent; generally marked variation in size and shape but atypia not necessarily extreme

Mitosis counts, which involve a pathologist counting cells with definite mitosis in 10 consecutive fields, result in a score of 1-3.

Final grading results from the addition of all the above, with a total score between the range of 3-9. Scores and grades are as follows:

  • Total score 3-5 = grade 1
  • Total score 6 or 7 = grade 2
  • Total score 8 or 9 = grade 3

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