Patient education: Breast cancer screening (Beyond the Basics)
- Joann G Elmore, MD, MPH
Joann G Elmore, MD, MPH
- Editor-in-Chief — Primary Care (Adult)
- Section Editor — General Medicine
- Professor of Medicine, Adjunct Professor of Epidemiology
- University of Washington School of Medicine
Breast cancer screening includes tests to detect breast cancer at an early stage, before a woman discovers a lump. Breast cancer is more likely to be cured when it is caught earlier. The chance of dying from breast cancer has declined by about a third over the past few decades. This is due, in part, to the use of breast cancer screening to find cancer at an earlier stage.
This article discusses what breast cancer screening includes, when to start, and how often to do it. Women with a high risk of breast cancer, such as those with a genetic mutation in BRCA1 or BRCA2 and those who have multiple close relatives with breast cancer, should review information about genetic testing and screening recommendations for higher-risk individuals. (See "Patient education: Genetic testing for breast and ovarian cancer (Beyond the Basics)".)
BREAST CANCER SCREENING METHODS
Screening for breast cancer primarily involves mammography. Regularly examination of the breast, either by a doctor, nurse, or patient herself, does not reduce breast cancer mortality but increases the chance of needing a breast biopsy.
Mammogram — A mammogram (“mammography”) is a breast X-ray. It is the best screening test for reducing the risk of dying from breast cancer.
Before the mammogram, you will be asked to undress from the waist up and wear a hospital gown. Each breast is X-rayed individually. The breast is flattened between two panels. This can be uncomfortable, but it only takes a few seconds. If possible, try to avoid scheduling your mammogram just before or during your menstrual period, when the breasts are more sensitive. Also, do not use underarm deodorant or powder on the day of your appointment.
Mammogram results — A radiologist will review and interpret the mammogram. Sometimes the radiologist reviews the mammogram images while you wait. Some women will need to have more images taken. Needing more images is common and does not usually mean that you have cancer. These extra images help the radiologist to have the most accurate and clear view of your breast tissue.
If the radiologist does not review your mammogram immediately, you should get a phone call or letter with your results within 30 days. If you do not hear back about your results, call your doctor or nurse's office, rather than assuming that your mammogram was normal.
What if my mammogram is abnormal? — If your mammogram is abnormal, you will need further testing. In fact, about 1 in every 10 women in the United States will have an abnormal mammogram requiring follow-up (most often a repeat mammogram with additional views). In most cases, a woman with an abnormal mammogram does not have breast cancer. In 90 percent of women with an abnormal mammogram, breast cancer is not found.
Follow-up testing after an abnormal mammogram is discussed separately. (See "Patient education: Common breast problems (Beyond the Basics)", section on 'Abnormal mammogram'.)
Breast exam by your doctor or nurse — Although your doctor or nurse might perform a breast exam, not all expert groups recommend having regular breast exams. "False positive" findings on breast exam (lumps or other findings that are not cancers) may lead to unnecessary breast biopsies and associated anxiety, but studies have not found that women who are screened with a breast exam along with a mammogram have better outcomes than women who are screened with mammography alone.
Breast self-exam — Breast self-exam is a way of finding changes in your own breasts. No study has shown that breast self-exam reduces the risk of dying from breast cancer. Thus, we do not recommend breast self-examination. However, some women feel that doing breast self-exams on a regular basis improves their ability to find changes that would otherwise not have been noticed. Some experts encourage breast self-awareness, which includes education about risk factors for breast cancer and what to do if a breast abnormality is detected. Women who want to perform breast self-exams should still continue to get regular mammograms because mammograms are better screening tests.
Instructions for performing a breast self-exam are provided here (table 1). The best time to perform breast self-exam is about one week after your menstrual period ends, when the breasts are least lumpy. If you do not have menstrual periods, you can pick one day each month.
Other imaging methods — Although other imaging methods (breast magnetic resonance imaging [MRI] and breast ultrasound) can detect breast cancer, mammography is the only imaging method studied for screening the general population that has been found to be associated with decreased death from breast cancer. Therefore, only mammography is recommended as a screening test for the general population of women who do not have a higher risk of breast cancer.
Breast MRI — MRI uses a strong magnet rather than X-rays to create a detailed image.
Compared with mammograms, breast MRI:
●Has more "false positive" findings (changes that are not breast cancer)
●May lead to more unnecessary biopsies in women who are not at high risk for breast cancer
●Is more expensive
Breast MRI may be recommended, in addition to mammography, to help find breast cancer in young women with a high risk for developing breast cancer (such as those with a very strong family history or a breast cancer gene). However, breast MRI is not recommended to screen for breast cancer in women who do not have a high risk of breast cancer.
Breast ultrasound — An ultrasound of the breast is often ordered as a follow-up test when a breast lump is found. An ultrasound is not, however, recommended as a routine test to screen for breast cancer in the general population who do not have a lump.
Dense breasts make it more difficult for the radiologist to interpret a mammogram. An ultrasound may be suggested in addition to screening mammography, when the mammogram finds that a woman’s breasts are very dense. There are no available studies showing that use of ultrasound for screening will improve breast cancer mortality outcomes. However, studies have shown that women who are screened with both mammograms and ultrasound tests are more likely to be referred for unnecessary breast biopsies, and so the benefit of adding ultrasound to mammography is not clear.
BREAST CANCER SCREENING RECOMMENDATIONS
When to start mammograms — The decision about whether or not to have a mammogram should be made by the woman, based on her personal values and advice from her clinician about risks and benefits. The risks and benefits of screening are related to a woman's age; benefits, in terms of numbers of lives saved, are lower for younger women than older women because the incidence of breast cancer is lower in younger women, while the chances of having an abnormal mammogram that must be worked up are higher.
Expert groups differ on their advice about when to start mammography. We recommend that mammography screening be discussed with all women aged 40 and older, and that the individual woman should be involved in making the decision whether or not she wants to have screening. Expert groups variably recommend initiating mammography screening at age 40, 45, or 50 [1-3].
How often to have a mammogram — It is not clear what the best schedule for mammography should be for every woman. We suggest screening every two years for most women; more frequent screening may also be advised for women at high risk of breast cancer, depending on the woman’s risk and her own personal values.
When to stop mammograms — Most expert groups recommend that women continue to get routine mammograms as long as the woman is expected to live at least 10 years. Women who have a lot of serious medical conditions that limit lifespan are not likely to benefit from screening mammography. (See "Patient education: Factors that modify breast cancer risk in women (Beyond the Basics)".)
WHERE TO GET MORE INFORMATION
Your health care provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Breast cancer screening (The Basics)
Patient education: Breast cancer (The Basics)
Patient education: Cancer screening (The Basics)
Patient education: Common breast problems (The Basics)
Patient education: Genetic testing for breast and ovarian cancer (The Basics)
Patient education: Breast reconstruction after mastectomy (The Basics)
Patient education: Choosing treatment for early-stage breast cancer (The Basics)
Patient education: Ductal carcinoma in situ (DCIS) (The Basics)
Patient education: Sentinel lymph node biopsy for breast cancer (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient education: Genetic testing for breast and ovarian cancer (Beyond the Basics)
Patient education: Common breast problems (Beyond the Basics)
Patient education: Factors that modify breast cancer risk in women (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Breast imaging for cancer screening: Mammography and ultrasonography
Clinical manifestations and diagnosis of a palpable breast mass
Factors that modify breast cancer risk in women
Genetic counseling and testing for hereditary breast and ovarian cancer
Overview of hereditary breast and ovarian cancer syndromes
Screening for breast cancer: Strategies and recommendations
The following organizations also provide reliable health information.
●National Cancer Institute
●National Library of Medicine
The editorial staff at UpToDate would like to acknowledge Suzanne W Fletcher, MD, who contributed to an earlier version of this topic review.
- Nelson HD, Tyne K, Naik A, et al. Screening for breast cancer: an update for the U.S. Preventive Services Task Force. Ann Intern Med 2009; 151:727.
- Oeffinger KC, Fontham ET, Etzioni R, et al. Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update From the American Cancer Society. JAMA 2015; 314:1599.
- Bevers TB, Anderson BO, Bonaccio E, et al. NCCN clinical practice guidelines in oncology: breast cancer screening and diagnosis. J Natl Compr Canc Netw 2009; 7:1060.
- Pace LE, Keating NL. A systematic assessment of benefits and risks to guide breast cancer screening decisions. JAMA 2014; 311:1327.
All topics are updated as new information becomes available. Our peer review process typically takes one to six weeks depending on the issue.