Breast Cancer Overview

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Early Detection, Diagnosis, and Staging TOPICS

Screening for breast cancer

The term screening refers to tests and exams used to find a disease like cancer in people who do not have any symptoms. The earlier breast cancer is found, the better the chances that treatment will work. The goal is to find cancers before they start to cause symptoms.

Tests used to screen for breast cancer


A mammogram is an x-ray of the breast. It uses a very small amount of radiation. A screening mammogram is used to look for breast disease in women who do not seem to have breast problems. A diagnostic mammogram is used to check out a problem or an abnormal result on a screening mammogram.

A technologist (most often a woman) will position your breast for the test. The breast is pressed between 2 plates to flatten and spread the tissue. The pressure lasts only a few seconds while the picture is taken. The breast and plates are repositioned and then another picture is taken. The whole process takes about 20 minutes. Although this may cause some discomfort for a moment, it is needed to get a good picture.

Mammograms might miss some cancers, but they are still a very good way to find breast cancer.

Clinical breast exam

A clinical breast exam (CBE) is an exam of your breasts by a health expert such as a doctor, nurse practitioner, nurse, or physician assistant. The area under both arms will also be checked.

Breast awareness and breast self-exam

Women should be aware of how their breasts normally look and feel and report any changes to a doctor right away. Finding a change does not mean that you have cancer.

A breast self-exam (BSE) is a step-by-step approach to checking your breasts for changes. This exam can be done on a schedule. For information on how to do BSE, see our document Breast Cancer Early Detection.

The best time to do BSE is when your breasts are not tender or swollen. If you find any changes, see a doctor right away.

It's OK for women not to do BSE or to do it once in a while.

MRI (magnetic resonance imaging)

MRI scans use magnets and radio waves (instead of x-rays) to produce very detailed, cross-sectional images of the body.

For a breast MRI, you have to lie face down on a special platform inside a narrow tube. The platform has openings for each breast that allow the image to be taken without pressing on the breast. Contrast material may be injected into a vein to help the MRI show more details of the breast tissue.

MRI scans can take a long time — often up to an hour. It is important to remain very still the entire time. Lying in the tube might upset people with a fear of enclosed spaces.

American Cancer Society recommendations for finding breast cancer early

The American Cancer Society (ACS) recommends the following guidelines for finding breast cancer early in women without symptoms:

Mammogram: Women age 40 and older should have a screening mammogram every year and should keep doing so for as long as they are in good health.

Clinical breast exam: Women in their 20s and 30s should have a clinical breast exam (CBE) as part of a regular exam by a health expert at least every 3 years. After age 40, women should have a breast exam by a health expert every year. It might be a good idea to have the CBE shortly before the mammogram.

Breast self-exam (BSE): BSE is an option for women starting in their 20s. Women should be told about the benefits and limits of BSE. Women should report any changes in how their breasts look or feel to a health expert right away.

Magnetic resonance imaging (MRI): Women at high risk based on certain factors should get an MRI and a mammogram every year. This includes:

  • Women who have about a 20% lifetime risk of breast cancer or higher based on family history
  • Women who had radiation therapy to the chest when they were between the ages of 10 and 30 years
  • Women who have mutations (abnormal changes) in certain genes that greatly increase their breast cancer risk or who haven’t been checked for these mutations but have close family members that have one of these mutations

More details about these guidelines, including information about what makes someone high risk can be found in our document Breast Cancer: Early Detection.

For more details about mammograms and breast MRI see our document Mammograms and Other Breast Imaging Procedures.

Last Medical Review: 09/09/2014
Last Revised: 09/09/2014