Frequently Asked Questions About the American Cancer Society’s Breast Cancer Screening Guideline

The American Cancer Society released its current breast cancer screening guideline for women at average risk in October, 2015. Here are some answers to questions people might ask about it.

How does this guideline differ from previous ACS guidelines?

The biggest change in the current guideline is that we now recommend that women at average risk for breast cancer start annual screening with mammograms at age 45, instead of age 40 (which was the starting age in our previous guideline). Women ages 40 to 44 can choose to begin getting mammograms yearly if they want to.

In addition, the guideline says that women should transition to screening every 2 years starting at age 55, but can also choose to continue screening annually.

The ACS no longer recommends a clinical breast exam (CBE) as a screening method for women in the U.S. Breast self-exam is also no longer recommended as an option for women of any age.

This guideline is for women at average risk for breast cancer, but how do I know if I am at average risk?

The best way to determine if you are at average or high risk for breast cancer is to talk with your health care provider about your family history and your personal medical history. In general, women at high risk for breast cancer include women with a family history of breast cancer in a first degree relative (mother, sister, or daughter), women with an inherited gene mutation, and women with a personal history of breast cancer. 

Why did ACS change its guideline to say routine screening should start at 45 instead of 40?

The evidence shows that the risk of cancer is lower for women ages 40 to 44 and the risk of harm from screenings (biopsies for false-positive findings, overdiagnosis) is somewhat higher. Because of this, a direct recommendation to begin screening at age 40 was no longer warranted. However, because the evidence shows some benefit from screening with mammography for women between 40 and 44, the guideline committee concluded that women in this age group should have the opportunity to begin screening based on their preferences and their consideration of the tradeoffs. That balance of benefits to risks becomes more favorable at age 45, so annual screening is recommended starting at this age.

Every life lost to cancer is important. But the fact is, even though mammography reduces deaths from breast cancer, it does not eliminate them, even in the age groups where it is agreed that women should be screened. The challenge of screening is maximizing the lifesaving benefits while minimizing its harms. These evidence-based guidelines represent the best current thinking on that balance.

What exactly should a woman do at age 40? Should she get screened or not? How should she decide?

The risk of breast cancer is lower in women between the ages of 40 to 44. Still, some women will choose to accept the greater chance of a false-positive finding and the harms that could come from that (biopsy pain and anxiety, for instance) as a reasonable tradeoff for potentially finding cancer. The decision about whether to begin screening before age 45 is one that a woman should make with her health care provider.

What about screening women in their 30s and younger? They get breast cancer, too. Doesn’t ACS care about that?

Cases of breast cancer in women who are in their 30s are rare, but that doesn’t make them any less tragic or important. The reason why none of the major guidelines recommend routine screening in this younger age group is because the evidence so far shows that the risk of harms such as false positive, additional procedures, and potential overdiagnosis outweighs the potential benefits. Additionally, routine screening for women in their 30s or younger doesn’t reduce deaths from cancer. The bottom line is that you can and should talk to your doctor about any concerns you have with your breast health at any age.

Why can women choose to start screening every 2 years at age 55?

Although breast cancer is more common in older women after menopause, breast cancer grows more slowly in most women, and is easier to detect early because the breasts are less dense. Since most women are post-menopausal by age 55, and because the evidence did not reveal a statistical advantage to annual screening in post-menopausal women, the guidelines committee concluded that women should move to screening every 2 years starting at age 55. Still, the guideline says women may choose to continue screening every year after age 55 based on their preferences.

Why is a clinical breast exam (CBE) no longer recommended?

Clinical breast examination (CBE) is a physical exam done by a health professional. During the beginning of the mammography era, the combination of CBE and mammography was associated with a lower risk of dying from breast cancer, and CBE was shown to offer an independent contribution to breast cancer detection. Since then, as mammography has improved and women’s awareness and response to breast symptoms has increased, the few studies that exist suggest that CBE contributes very little to early breast cancer detection in settings where mammography screening is available and awareness is high.

In addition, there was moderate evidence that doing CBE along with mammography increases the rate of false positives. Based on this information, the current guideline does not recommend CBE for US women at any age.  

There are settings in the US where access to mammography remains a challenge, and the American Cancer Society will continue to work to ensure that all women have access to mammography screening. We recognize that some health care providers will continue to offer their patients CBE, and there may be instances when a patient decides with their health care provider to have the exam- and that's OK. The important message of our guideline is that CBE should not be considered an acceptable alternative to mammography screening, no matter the challenges of access to mammography.

Why is a breast-self-exam no longer an option for women in the guidelines?

Evidence does not show that regular breast self-exams help reduce deaths from breast cancer. However, it is very important for women to be aware of how their breasts normally look and feel and to report any changes to a health care provider right away. This is especially important if a woman notices a breast change at some point in between her regular mammograms.

What are the limitations of mammography and why is it important for women know about them?

Mammography is the best test we have at this time to find breast cancer early, but it has known limitations -- it will find most, but not all, breast cancers. The American Cancer Society supports informing women about the limitations of mammography so they will have reasonable expectations about its accuracy and usefulness. Studies show that informing women of the limitations of mammography before they have one decreases anxiety and improves later adherence with screening recommendations.

The accuracy of mammography improves as women age – thus, accuracy is slightly better for women in their 50s than women in their 40s and slightly better for women in their 60s than women in their 50s, and so on. However, a woman undergoing breast cancer screening needs to know that mammography at any age is not 100% accurate. Overall, mammography will detect about 85% of breast cancers.

Women also need to be prepared for the possibility of being called back for additional testing, even though most women who get further testing do not have breast cancer. On average, about 10% of women are recalled for further evaluation, including additional mammography and/or ultrasound, and sometimes a biopsy to determine if cancer is present.

Women also need to know that if their mammogram result is normal, but they detect a symptom months later before their next mammogram, they should see a doctor right away.

What about women who are at higher risk?

The American Cancer Society has separate recommendations for women at increased risk for breast cancer.

Why are there no recommendations for 3D mammography (tomosynthesis)?

Although digital breast tomosynthesis units are steadily being introduced in mammography facilities, at the time the protocol for the evidence review was developed, there was too little data on digital breast tomosynthesis to include comparisons to 2D mammography. The issue will continue to be revisited and will be updated as evidence emerges.

Will this guideline affect my ability to get a mammogram?

Insurance coverage is usually linked to U.S. Preventive Services USPSTF (USPSTF) screening recommendations, not ACS guidelines. The American Cancer Society strongly believes that women between the ages of 40 and 44 and women over the age of 55 should have access to annual mammograms without being charged a co-pay. To be sure, you may want to check with your health insurance company before scheduling a mammogram.

How was the American Cancer Society’s screening guideline developed?

The Society’s guideline development process is transparent, consistent, and rigorous process that is closely aligned with Institute of Medicine (IOM) standards. The Society’s guidelines are now developed by the American Cancer Society Guideline Development Group (GDG), a voluntary panel of generalist clinicians, biostatisticians, epidemiologists, economists, and patient representatives. The Society’s breast cancer screening guideline was developed in accordance with this process, and utilized a systematic evidence review of the breast cancer screening literature that was conducted independently by the Duke University Evidence Synthesis Group.

There were no representatives from the health insurance industry on the GDG, and all GDG members are required to disclose potential conflicts of interest before they are accepted for participation. In addition, under this process, costs to the health care system and reimbursement of costs by insurers are not factors considered in the review of evidence and development of recommendations by the GDG.