The short answer
Bilateral risk-reducing mastectomy lowers breast cancer risk by at least 95% in people with a harmful BRCA1 or BRCA2 variant — but not to zero, because some breast tissue always remains. High-risk surveillance with annual mammography and MRI is a real alternative with a different goal. There is no single right answer.
More than 60% of women who inherit a harmful BRCA1 or BRCA2 variant develop breast cancer, compared with about 13% in the general population.
Bilateral risk-reducing mastectomy reduces breast cancer risk by at least 95% in BRCA1/BRCA2 carriers, and by up to 90% in women with a strong family history.
Risk does not fall to zero because it is impossible to remove all of the breast tissue that may be at risk.
The alternative is not doing nothing: high-risk surveillance means annual mammography plus annual breast MRI, often alternated so imaging happens every six months. The ACS says screening typically starts at age 30.
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The whole article, with every detail and caution.
This page is for people with an inherited cancer risk who are weighing surgery to remove both breasts. It covers what the operation can and cannot do, the options, the alternative of close screening, and practical questions to raise.
Start with your actual numbers
More than 60% of women who inherit a harmful BRCA1 or BRCA2 variant develop breast cancer. In the general population, about 13% of women do. NCI also lists harmful changes in TP53 and PTEN as reasons to consider surgery. Their risk figures are different, so ask about yours.
Ask for the number attached to your specific gene, your specific variant and your own family history. Do not work from a general figure for "inherited risk." Risk-reducing mastectomy is also discussed for people with pleomorphic lobular carcinoma in situ (a type of abnormal cell growth in the breast's milk glands) plus a strong family history. It is discussed too for people who had chest radiation before age 30.
What the surgery does, and does not, do
Bilateral risk-reducing mastectomy is surgery to remove both breasts before any cancer appears. It reduces breast cancer risk by at least 95% in women with a harmful BRCA1 or BRCA2 variant, and by up to 90% in women with a strong family history. These figures come from the National Cancer Institute’s “Surgery to Reduce the Risk of Breast Cancer.”
Not 100%. NCI says it is impossible to remove all of the breast tissue that may be at risk.
It also does not change ovarian, tubal or peritoneal risk. That is a separate decision and a separate operation.
The versions of the operation
- Total (simple) mastectomy removes the breast tissue along with the nipple and areola. It gives slightly greater risk reduction.
- Skin-sparing keeps the skin envelope. Nipple-sparing also keeps the nipple and areola. That allows a more natural-looking reconstruction, but it leaves slightly more tissue behind.
- Reconstruction may use implants or your own tissue. It can be done at the same operation or later, in one stage or several. Some people choose not to reconstruct at all.
NCI notes that nipple sensation is lost with total mastectomy, which may affect sexual function. Ask your surgeon how much feeling in the chest to expect. Ask what reconstruction involves and how many procedures it may take.
The alternative is not "doing nothing"
High-risk surveillance is an active plan. For people at high risk it generally means a yearly mammogram and a yearly breast MRI. The ACS says this typically starts at age 30. NCI describes imaging that alternates so a test happens every six months. Risk-lowering medicines such as tamoxifen or raloxifene are options for some people.
Surveillance aims to find cancer early. Surgery aims to prevent it. Those are genuinely different goals, and people weigh them differently for good reasons.
Why this is preference-sensitive
The evidence shows how much breast cancer risk goes down. Ask your team what is known about how surgery compares with close screening for living longer. The decision also turns on things evidence cannot rank for you:
- How you experience surveillance — as reassurance, or as a yearly ordeal you dread for weeks beforehand.
- How you feel about your body, about sensation, and about reconstruction.
- Your age, whether you plan to breastfeed, and where you are in life.
- What you watched happen in your family.
- How well you can live alongside a known, measured risk.
Talk through the timing with your team. Many people take time to decide, and screening can continue in the meantime.
Practical things people wish they had asked earlier
Reconstruction often involves a plastic surgeon as well as a breast surgeon. Ask to meet both before deciding. Ask what recovery will look like and how it fits with work and caregiving.
In the US, the Women's Health and Cancer Rights Act (CMS) requires plans that cover mastectomy to also cover all stages of reconstruction, surgery on the other breast for symmetry, and prostheses. Ask your plan for the specifics in writing.
And if you are considering this, it is worth seeing a genetic counselor again, even if you already have your result. Ask whether your result or risk estimate has changed since you were first told.
Sources
- NCI — Surgery to Reduce the Risk of Breast Cancer
- NCI — BRCA Gene Changes: Cancer Risk and Genetic Testing
- American Cancer Society — Recommendations for the Early Detection of Breast Cancer (high-risk MRI screening)
- CMS — The Women's Health and Cancer Rights Act (reconstruction coverage)
- NCI — Genetic Testing for Inherited Cancer Susceptibility Syndromes
Common questions
Why does risk not drop to zero?
NCI says it is impossible to remove all of the breast tissue that may be at risk. That is why the figure is 'at least 95%' rather than 100%. Ask your team what follow-up you will need.
Does preventive mastectomy help me live longer?
The NCI figures describe how much breast cancer risk falls. Ask your team what is known about survival compared with close screening. Many people weigh personal preferences too.
Is nipple-sparing mastectomy as protective?
Total mastectomy, which removes the nipple and areola, gives slightly greater risk reduction because it leaves less tissue behind. Nipple-sparing surgery preserves more natural appearance after reconstruction. Both are offered; which is appropriate depends on your anatomy, your tumor risk profile and your surgeon's assessment.
Do I have to decide soon?
Ask your team about timing. Many people take time to decide, and a screening plan can run in the meantime.
Will insurance cover reconstruction?
In the US, plans that cover mastectomy must also cover all stages of breast reconstruction, surgery on the other breast for symmetry, and prostheses, under the Women's Health and Cancer Rights Act (CMS). Ask your plan for the specifics in writing.
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Written by: Cancer ExplainedSources last checked: 2026-07-30 what this meansLast updated: 2026-10-02Next planned review: 2027-07-30
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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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