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.
Clinical breast exams and self-exams alone are not considered adequate screening tests.
Screening has real benefits, including earlier detection, but also possible harms, including false positives and overdiagnosis.
Choose how you want to understand this
The full explanation.
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.
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. On its own, this is not considered an adequate screening test.
- Breast self-exam. Helps you notice changes in your own breasts, but 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
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 suggest a different age or a yearly 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.
Why it matters
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 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
Words to know
Tap any term to see what it means.
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. Many guidelines suggest women at average risk consider starting in their 40s, with regular screening through at least their mid-70s. 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. Some centres and some state laws offer extra imaging anyway. 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. Breast self-exams can help you notice changes, but they are not considered an adequate screening test on their own, and neither is a clinical breast exam by a provider.
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.
Questions to ask your doctor
Being prepared helps you get the most out of your appointments. Save or print these questions.
Tap a question to save it to your list (kept on this device).
Speak With Trained Specialists & Human Navigators
Cancer Explained provides educational guidance, but does not replace trained specialists, social workers, or your medical team.
Talk to a trained cancer information specialist
Free, confidential assistance from NCI Cancer Information Service via phone, chat, or email.
Contact your oncology team
Locate after-hours contact numbers, portal messages, or urgent triage phone lines.
Find a patient navigator
Get one-on-one help with appointments, logistics, translation, and care coordination.
Find a genetic counselor
Discuss inherited mutation risk, family history, and genetic testing options.
Find an oncology social worker
Access emotional counseling, family support groups, and mental health resources.
Find a financial navigator
Locate copay assistance foundations, grant programs, and lodging/travel support.
Find a clinical-trial specialist
Search matching studies and speak with NCI trial information specialists.
Get urgent help
Immediate emergency guidance for fever (>100.4°F during chemo), severe pain, or shortness of breath.
Help Us Improve This Guide
Did this explanation answer your question and help you determine your next step?
Know someone who needs this?
Plenty of people are looking for something like this and do not know where to start. If this would help a friend or someone you love, send it on — we have written an opening line so you do not have to stare at an empty message. You can change every word of it.
Your message is written and sent in your own email or messaging app — we never see who you send it to, and nothing is added to any list.
Plain-language explanation of the published sources cited on this page. AI-assisted, source-checked, not clinician-reviewed.
Last updated: 2026-08-19Next planned review: 2027-08-03
How this page was created
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. We do not employ clinicians and do not intend to — our work 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 checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
General education — varies by person. Answers genuinely differ between people. This page explains what commonly varies and points you to your care team 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.
How this page was created
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. We do not employ clinicians and do not intend to — our work 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 checked line by line against the sources listed on it. That confirms the sources support what the page says. 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.
Read more about our editorial process, our use of AI, and our corrections policy.
Spotted a problem? Report an error — a factual mistake, broken or outdated source, confusing wording, or anything that seems unsafe. Please do not include names, medical record numbers, dates of birth, addresses, or other identifying medical information in your report.
After using this page, do you understand what to do next?
Anonymous — we only record the answer, never who gave it.
Related articles
Still have questions?
Educational answers, plain language
Free to print and share