Invasive Cancer Grading

The pathologist grades invasive breast cancer cells based on their appearance during a laboratory examination in which the cells are examined under a microscope. This determination can indicate how aggressive a cancer may be.

The histologic grading system (sometimes called the Elston-Ellis modification of the Scarff-Bloom-Richardson grading system) takes into account the arrangement of cells in relation to one another as well as the features of individual cells. The system assesses the appearance of cancer cells as compared to normal cells.

The cells are given a certain number of points on a scale based on their characteristics and then graded accordingly. If the cells are recognizable because they look a lot like the cells of the tissue in which they originated, they're called "well differentiated" (usually Grade I). If they no longer resemble breast cells, they're said to be "poorly differentiated" and have a higher grade (usually Grade III). Generally, the higher the grade, the more aggressive the cancer.

Understanding tumor grades

Grade I (cells well differentiated)
Score of 3-5 points on the scale. These are normal-looking cells that do not appear to be growing rapidly. Such a low-grade tumor tends to grow and spread more slowly and has a better outlook than more aggressive cancers.

Grade II (cells moderately differentiated)
Score of 6-7 points on the scale. The characteristics of these tumors fall between Grades I and III.

Grade III (cells poorly differentiated)
Score of 8-9 points on the scale. These cells lack features of the tissue of origin and tend to grow more quickly and spread more aggressively.

Next >> Receptors: Estrogen, Progesterone & HER2/neu

In This Article:
Diagnosing Breast Cancer
Tumor Staging and Tumor Margins
Invasive Cancer Grading
Receptors: Estrogen, Progesterone & HER2/neu

From the Harvard Health Publications Special Health Report, Breast Cancer: Strategies for Living. Copyright 2004 by the President and Fellows of Harvard College. Illustrations by Harriet Greenfield, M.A., and Jesse Tarantino. All rights reserved. Used with permission of StayWell. Harvard Medical School does not endorse products.
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