Skip to content
My WebMD Sign In, Sign Up

Breast Cancer Health Center

Font Size

Breast Cancer Classification - Topic Overview

Breast cancer is the abnormal growth of the cells that line the ducts and lobes of the breast. The classification of breast cancer is based on:

  • Whether the cancer started in the ducts or the lobules of the breast.
  • Whether the breast cancer cells have invaded other tissue in the breast.
  • What the cancer cells look like under the microscope.

Classification also takes into consideration such information as how rapidly the cancer cells are multiplying (tumor grade) and whether breast cancer cells are present in the nearby lymph nodes.

Recommended Related to Breast Cancer

I'm Too Young to Get Breast Cancer!

By Amy Engeler On September 2 of last year, Tomomi Arikawa left her office door open as she slipped out to her two o'clock sonogram appointment. She expected to return shortly — the imaging center was just across town from her office at ABC News, where she was a story editor for 20/20. At her gynecologist's urging, Tomomi was going to have a tender lump in her right breast checked out. The lump felt squishy, like a piece of Bubble Wrap, not like a hard kernel or a marble or any of the objects tumors...

Read the I'm Too Young to Get Breast Cancer! article > >

The following classifications describe the most common types of breast cancer.

  • In situ: A tumor that hasn't spread beyond the area where it began is called in situ.
  • Infiltrating (invasive) ductal carcinoma (IDC): This cancer starts in a milk duct, breaks through the wall of the duct, and invades the fatty tissue of the breast. From there, it can spread to other parts of the body. IDC is the most common type of breast cancer, accounting for nearly 80% of cases.
  • Infiltrating (invasive) lobular carcinoma (ILC): This cancer starts in the mammary, or milk, glands (lobules) and can spread to other parts of the body. About 10% of breast cancers are this type.
1

WebMD Medical Reference from Healthwise

Last Updated: June 28, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
Next Article:

Breast Cancer Classification Topics

Today on WebMD

Breast Cancer Overview
From self-exams and biopsies to reconstruction, we’ve got you covered.
Dealing with breast cancer
Get answers to your questions.
 
woman having mammogram
Experts don’t agree on all fronts, but you can be your own advocate.
woman undergoing breast cancer test
Many women worry. But the truth? Most abnormalities aren’t breast cancer.
 
Breast Cancer Treatments Improving
VIDEO
Resolved To Quit Smoking
SLIDESHOW
 
Woman getting mammogram
Article
Screening Tests for Women
SLIDESHOW
 
ovarian cancer overview slideshow
SLIDESHOW
serious woman
Article
 
what is your cancer risk
HEALTH CHECK
10 Ways to Revitalize Slideshow
SLIDESHOW