Breast Cancer: Screening

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ON THIS PAGE: You will find out more about screening for breast cancer. You will also learn the risks and benefits of screening. Use the menu to see other pages.

Screening is used to look for cancer before you have any symptoms or signs. Scientists have developed, and continue to develop, tests that can be used to screen a person for specific types of cancer. The overall goals of cancer screening are to:

  • Lower the number of people who develop the disease

  • Lower the number of people who die from the disease, or eliminate deaths from cancer altogether

  • Identify people with a higher risk of developing a specific type of cancer who may need screening more often due to genetic mutations or diseases

Learn more about the basics of cancer screening.

Screening Information for Breast Cancer

Mammography

Mammography is the best tool doctors have to screen healthy women for breast cancer, as it has been shown to lower deaths from the disease. Like any medical test, mammography involves risks, such as the possibility of additional testing and anxiety if the test falsely shows a suspicious finding, called a "false-positive" result. Up to 10% to 15% of the time, mammography will not show an existing cancer, called a "false-negative" result.

Digital mammography may be better able to find breast cancers, particularly in women with dense breasts. A newer type of mammogram is called tomosynthesis or 3D mammography. It may improve the ability to find small cancers and reduce the need to repeat tests due to false-positives. However, there is also the risk of diagnosing problems in the breast that would otherwise go unnoticed and would not lead to any negative consequences. This is called "overdiagnosis" and may lead to overtreatment with a potential for harm. This method is approved by the FDA, though research on it is ongoing.

Other breast cancer screening methods

Other ways to examine the breasts, such as an ultrasound and/or a magnetic resonance imaging (MRI) scan, are not regularly used to screen for breast cancer in many women at average risk. But these tests may be helpful for women with a very high risk of breast cancer, those with dense breast tissue, or when a lump or mass is found during a breast examination. The use of ultrasound screening is controversial because it has a high false-positive rate. This means that the test often wrongly identifies potential cancers. MRI use in routine screening is also controversial.

According to the American Cancer Society (ACS), women who have BRCA gene mutations, who have a very strong family history of breast cancer, or who had prior radiation therapy to the chest should consider mammography and MRI each year.

Women at moderate risk of breast cancer, such as women with precancerous changes on a biopsy, can talk with their doctor about whether MRI screening should be considered.

MRI may be better than mammography and ultrasound at finding a small mass in a woman’s breast, especially for women with very dense breast tissue. However, an MRI has a higher rate of false-positive test results, which may mean more biopsies, surgeries, and other tests that may lead to overdiagnosis. In addition, an MRI does not show tiny spots of calcium called calcifications that can be found on a mammogram. Calcifications can be a sign of non-invasive breast cancer (DCIS). However, MRI can still be used to detect DCIS.

Ultrasound or MRI may also be used for women with a suspicious breast finding on physical examination or mammography. If a lump or mass is found during a physical examination, further testing with ultrasound or mammography may be needed.

Women are encouraged to talk with their doctor about the method of screening recommended for them and how often screening is needed.

Screening recommendations

Different organizations have looked at the evidence, risks, and benefits of mammography and have developed different screening recommendations. Decisions about screening for breast cancer are becoming increasingly individual. It is important for each woman to talk with their doctor about how often they should receive screening and which tests are most appropriate.

  • The U.S. Preventive Services Task Force (USPSTF) recommends that women ages 50 to 74 have mammography every 2 years. They recommend that mammography be considered in women ages 40 to 49 after evaluating the risks and benefits of this test with a doctor.

  • ACS recommends that women ages 40 to 44 have the choice to start yearly mammography. They recommend that women ages 45 to 54 receive mammography every year and that women 55 and older can switch to having a mammogram every 2 years or continue yearly screening, if they choose.

Other groups also provide recommendations regarding screening, including the American College of Radiology and the Society of Breast Imaging. Both recommend annual mammography starting at age 40. Some international groups do not recommend routine population-based screening for any age, but instead recommend an individualized approach.

The controversy about screening mammography is related to the ability of early detection to lower the number of deaths from breast cancer. Breast cancers detected by mammography are often small. In contrast, rapidly growing, aggressive cancers are more commonly found in between screening mammograms. They are called interval cancers. Interval cancers are more aggressive than screen-detected cancers and lead to more deaths compared to screen-detected cancers. They are also more frequently found in young women.

For women at higher risk of developing breast cancer, screening may be recommended at an earlier age and more often than the schedules listed above. Some older women may stop screening at some point, especially if they have significant health problems that limit the length of their life or ability to go through the physical demands of breast cancer treatment. This is why it is important for all women to talk with their doctors about breast screening and decide on an appropriate screening schedule.

The USPSTF and ACS also differ on their recommendations for clinical breast examinations. A clinical breast examination is when a doctor or other health care professional performs a physical examination of your breasts to check for abnormalities or lumps. The USPSTF recommends a clinical breast examination along with mammography. The ACS does not recommend a clinical breast examination for women with an average risk of developing breast cancer.

Finally, although breast self-examination has not been shown to lower deaths from breast cancer, it is important for women to become familiar with their breasts so that they can be aware of any changes and report these to their doctor. Cancers that are growing more quickly are often found through breast examinations in between regular mammograms.

The next section in this guide is Symptoms and Signs. It explains what body changes or medical problems breast cancer can cause. Use the menu to choose a different section to read in this guide.