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Breast Cancer Screening: Research and Guidelines

PD Beauty and Health LS012552 In 2016, the United States Preventive Services Task Force (USPSTF) released updated guidelines for breast cancer screening. The updates called for changes in well-known current practices for mammograms and breast exams. These changes caught a great deal of media attention and raised public confusion and concern.

Breast Cancer Screening

Breast cancer screening tests are designed to find cancer in people who do not have symptoms. The hope is that finding cancer earlier will prevent cancer deaths. Research has tried to measure how well screening tests are doing this. Current breast cancer screening options include mammograms and a breast exam by a healthcare provider.
The USPSTF is a panel of experts in medicine that reviews research and develops guidelines for disease prevention and screening. The American Cancer Society (ACS) and American Congress of Obstetricians and Gynecologists (ACOG) also provide guidelines for screening. These organizations create their guidelines based on their interpretation of current research.
Below are guidelines from USPSTF, ACS, and ACOG and summaries of current research. These guidelines and evidence summaries are for women with no symptoms or family history of breast cancer.
Age-Based Guidelines for Mammograms in Women 40-49 years 50-74 years 75 years and older
USPSTF Individualized screening*
(no routine screening)
Every 2 years No specific recommendation
ACS Individualized screening* (40-44 years)
Every year (45-54 years)

Start transitioning to every 2 years or continue yearly mammograms (55-74 years)
Every 2 years or yearly for women in good health who expect to live another 10 years
ACOG Individualized screening*
(no routine screening)
Every 1-2 years (50-75 years) Make a decision with your healthcare provider about whether you should continue screening
*Individualized screening is the decision to start screening every 1-2 years before the age of 50 years. It should be based on each person’s values regarding specific risks and benefits after a discussion with your doctor.
Clinical Breast Exam Breast Self-exam
USPSTF No recommendations were made* Not recommended*
ACS Not recommended* Not recommended*
ACOG May be offered*
Every 1-3 years for women aged 25-39
Every year starting at age 40
Not recommended*
*Breast self-awareness is very important at any stage of life. Be aware of any changes, such as new or disappearing lumps, clear or bloody nipple discharge, dimpling or thickening of the skin, pain, or a feeling of fullness in the underarm area. Not all breast cancers cause symptoms and not all breast changes are caused by cancer, but it is important to discuss these with your doctor so they can determine if further testing is needed.

Mammograms

There have been many studies on mammograms, but they were not done perfectly. As a result, experts analyzing the research may reach different conclusions.
For women 40-69 years, regular mammograms appear to reduce the risk of dying from breast cancer. There is little evidence about the benefit of mammograms in women aged 70 years or older.
Studies suggest that screening starting at age 40 provides a small reduction in the risk of dying from breast cancer when compared to starting screening at age 50. No change in the overall risk of dying for any reason has been shown, just a slight risk in dying from breast cancer. There is also a chance of having abnormal test results that are not cancer. This can lead to unnecessary tests, procedures, and stress.
Here is an example of the effect of mammography for women 40-49 years. If 1,000 women in this age group get a screening mammogram:
  • One woman will have a cancer that is not seen on the mammogram
  • 100 will have an abnormal mammogram. Out of these women:
    • 90 will be watched more closely with imaging, but not have a biopsy
    • 10 of these women with an abnormal mammogram will have a biopsy (to determine if cancer is present)
      • 8 of these women will not have cancer
      • 2 of these women will have cancer discovered
Here is an example of the effect of mammography for women aged 50-69 years. If 1,000 women in this age group get a screening mammogram:
  • One woman will have a cancer that is not seen by the mammogram
  • 83 will have an abnormal mammograms. Out of these women:
    • 72 will be watched more closely with imaging, but not have a biopsy
    • 11 will have a biopsy (to determine if cancer is present)
      • 7 of these women will not have cancer
      • 4 of these women will have cancer discovered

Clinical Breast Exam by Healthcare Professional

There is very little evidence about the clinical breast exam. One study suggests a clinical breast exam may be as helpful as a mammogram.

Breast Self-Exam

There are studies comparing women who regularly check their breasts and women who do not. These studies all show no effect on the risk of dying from breast cancer. These studies do show an increase in finding lumps that are not cancer. This can lead to unnecessary medical tests, procedures, and stress.
If you are interested in self-exam, get instructed on the proper technique. It is more important to have breast self-awareness so you can report any breast changes to your healthcare provider.

Final Decisions

This information can be confusing. Your age, overall health status, and family history of cancer may affect your decision to have screening tests. Discuss the risks and benefits of breast cancer screening specific to you with your healthcare provider.

RESOURCES

American Congress of Obstetricians and Gynecologists
http://www.acog.org
US Preventive Services Task Force
http://www.uspreventiveservicestaskforce.org

CANADIAN RESOURCES

Canadian Breast Cancer Foundation
http://www.cbcf.org
Canadian Cancer Society
http://www.cancer.ca

References

ACOG revises breast cancer screening guidance: Ob-Gyns promote shared decision making. American Congress of Obstetricians and Gynecologists website. Available at: https://www.acog.org/About-ACOG/News-Room/News-Releases/2017/ACOG-Revises-Breast-Cancer-Screening-Guidance--ObGyns-Promote-Shared-Decision-Making. Published June 22, 2017. Accessed August 1, 2017.
Breast cancer screening. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T361086/Breast-cancer-screening. Updated July 13, 2017. Accessed July 31, 2017.
Mammography for breast cancer screening. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115728/Mammography-for-breast-cancer-screening. Updated July 13, 2017. Accessed July 31, 2017.
Smith RA, Manassaram-Baptiste D, Brooks, et al. Cancer screening in the United States, 2015: A review of current American Cancer Society guidelines and current issues in cancer screening. CA Cancer J Clin. 2015;65(1):30-54.
US Preventitive Services Task Force. Screening for breast cancer: U.S. Preventive Services Task Force recommendation statement. Ann Intern Med. 2009;151(10):716-726.
8/12/2011 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T361086/Breast-cancer-screening: American Congress of Obstetricians and Gynecologists. Practice bulletin no.122: Breast cancer screening. Obstet Gynecol. 2011;118(2 Pt 1):372-382.
7/17/2017 DynaMed Plus Systematic Literature Surveillance http://www.dynamed.com/topics/dmp~AN~T361086/Breast-cancer-screening: Committee on Practice Bulletins—Gynecology. Practice bulletin number 179: breast cancer risk assessment and screening in average-risk women.

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