The short answer
Mammography is the standard breast cancer screening test. Breast MRI is added for people at high risk. Whether extra scans help women with dense breasts is still an open question. Screening can find cancer early, but it also carries possible harms like false positives and overdiagnosis.
Mammography is the main screening test for breast cancer in the general population.
Breast MRI is recommended alongside mammography for people at high risk, such as those with certain inherited gene changes or chest radiation in youth. Dense breasts alone are a different and unsettled question: the USPSTF says there is not yet enough evidence to recommend for or against extra ultrasound or MRI after a normal mammogram.
NCI says there is no proven death benefit from breast self-exam, and evidence for clinical breast exam is insufficient.
Screening has real benefits, including earlier detection, but also possible harms, including false positives and overdiagnosis.
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This page is for people deciding about breast cancer screening. It covers the tests, when to start, and the benefits and possible harms.
The simple version
Screening means checking for cancer before there are any symptoms. For breast cancer, the standard screening test is a mammogram. Other tests, like MRI, are sometimes added for people at higher risk.
Breast cancer screening tests
- Mammography. An x-ray of the breast. This is the standard, most widely used screening test.
- Breast MRI. Uses magnetic fields and radio waves instead of radiation. It is generally added to mammography for people at high risk, such as those with certain inherited gene changes, because it can detect some cancers that mammography misses. It is sometimes offered to women with dense breasts too, but that use sits on weaker ground: the USPSTF found the evidence insufficient to recommend for or against it after a normal mammogram.
- Breast ultrasound. Uses sound waves and is sometimes offered alongside mammography for people with dense breasts, though it has not been shown to clearly improve health outcomes on its own.
- Clinical breast exam. A provider manually checks for lumps. Evidence that it lowers deaths is insufficient, so it is not a substitute for a mammogram.
- Breast self-exam. NCI reports no death benefit from regular self-exam. It is not a substitute for screening tests.
In short: mammography is the standard test, with MRI sometimes added for people at higher risk.
When to start screening
Guidelines vary between expert groups. The U.S. Preventive Services Task Force recommends a mammogram every two years for women aged 40 to 74. Other groups may suggest a different age or schedule. If you have a family history of breast cancer, an inherited gene change, or other risk factors, your doctor may suggest starting earlier or adding other tests.
Benefits and possible harms
Finding breast cancer through screening, before it causes symptoms, means treatment can often start earlier. That is the main benefit.
Screening also carries possible harms:
- False positives. A result that looks abnormal but turns out not to be cancer, requiring more tests or a biopsy.
- Overdiagnosis. Finding a cancer that was growing so slowly it might never have caused a problem.
- False negatives. Missing a cancer, especially in dense breast tissue, which can delay diagnosis.
- Radiation exposure. Mammograms involve a small amount of radiation, generally considered low-risk.
Weighing the trade-offs
No screening test is perfect. Understanding both the benefits and the possible harms can help you have an informed conversation with your doctor about the screening plan that is right for you.
When to get help sooner
Screening is meant for people who have no symptoms. If you notice a change in your breast, do not wait for your next scheduled mammogram. Most breast changes turn out not to be cancer, but they still need to be looked at.
- Call your care team right away, the same day, if the skin of one breast turns red or darker, becomes swollen, or looks dimpled or puckered over a few days.
- Call your care team within a day or two if you find a new lump or thick, firm area in a breast or under an arm; if fluid other than breast milk leaks from a nipple; if a nipple flattens or changes direction; or if the skin of the breast, nipple, or areola becomes scaly, swollen, or itchy.
Sources
Common questions
What is a mammogram?
A mammogram is an x-ray picture of the breast. It is the standard screening test for breast cancer and can find changes before they can be felt.
When should I start getting mammograms?
Recommendations vary by expert group. The USPSTF recommends a mammogram every two years for women aged 40 to 74. Other groups may differ. Your personal and family history may change this timeline, so it's worth discussing with your doctor.
Do I need a breast MRI too?
MRI is generally recommended in addition to mammography for people at higher-than-average risk, such as those with certain inherited gene changes or a strong family history. Dense breasts are a separate question and not the same indication. Nearly half of women have dense breasts, and the USPSTF says the evidence is not yet there to recommend for or against adding ultrasound or MRI after a normal mammogram in that group — an I statement, meaning unsettled rather than unhelpful. Talk it through against your whole risk picture. MRI is not a routine test for people at average risk.
Is a breast self-exam enough on its own?
No. NCI reports no death benefit from breast self-exam, and the evidence for clinical breast exam is insufficient. Knowing how your breasts normally look and feel can still help you notice changes to report.
What are the downsides of screening?
Screening can lead to false positives, meaning extra tests or biopsies for something that turns out not to be cancer. It can also lead to overdiagnosis, finding a slow-growing cancer that may never have caused problems. Mammograms also involve a small amount of radiation. These possible harms are weighed against the benefit of finding cancer earlier.
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Last updated: 2026-10-02Next planned review: 2027-08-03
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Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes, and this is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and then compared with the sources listed on it, looking for statements those sources do not back up. That check is not a sentence-by-sentence record and can miss errors. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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