What Is a Prophylactic Mastectomy, and How Much Does It Lower the Risk of Breast Cancer?

Breast cancer is diagnosed in 1 in every 8 women in the U.S. at some point in their lifetime, and the risk of breast cancer nearly doubles in women with a family history of the disease. There are other factors that can increase someone’s risk as well, such as certain genetic mutations or a history of prior radiation treatment. So some people elect to remove their breast tissue to lower their risk. This procedure is called a bilateral prophylactic mastectomy (BPM). 

We’ll review the benefits and risks of this procedure, and other preventative options for those at high risk for breast cancer. 

Who might consider a prophylactic mastectomy?

A bilateral prophylactic mastectomy is only recommended for people at particularly high risk of breast cancer. This is because it’s a major surgical procedure that has its own associated risks (more on these below). A BPM may be offered as an option for people who have:

• Certain genetic mutations that increase their risk of breast cancer

• A significant family history of breast cancer

• A history of radiation treatment to the chest at a young age

People who have certain genetic mutations 

The most common genetic mutation that increases someone’s risk of developing breast cancer is one of the BRCA mutations (BRCA1 and BRCA2). The normal version of this gene helps protect us from cancer by repairing DNA when it has been damaged. But the mutated versions are less effective at this, making it easier for cancerous cells to develop. 

The risk for people with a BRCA mutation is about 70%, compared to a 12% lifetime risk of breast cancer for women in the U.S. who don’t carry this mutation.

There are other genetic mutations that have also been linked to a higher risk of breast cancer. A few of these include:

• PTEN (Cowden syndrome)

• TP53 (Li Fraumeni syndrome)

• STK11 (Peutz-Jeghers syndrome)

• PALB2

These are less common, and their associated risk varies from very high to moderate. But people who have one of these mutations are more likely to develop breast cancer than those who don’t.

People with an extensive family history of breast cancer

Even though we have identified several genetic mutations that increase the risk of developing breast cancer, there are likely many more mutations that have not yet been discovered. We know this because breast cancer often runs in families, even though we can’t always link this to a specific gene. In fact, this is the case for most familial cases of breast cancer. So those with a strong family history of breast cancer may also consider undergoing BPM. People for whom this applies include those with:

• Multiple relatives who developed breast or ovarian cancer

• A first degree relative — parent, sibling, or child — diagnosed with breast cancer in both breasts, or before the age of 50

People with a history of exposure to chest radiation

People with a history of radiation treatment to the chest before age 30 are also at risk of developing breast cancer. This includes those who were treated with radiation for certain cancers, such as Hodgkin lymphoma. Radiation exposure increases the risk of cancer because it can damage cells in a way that makes them more likely to become cancerous. Studies have shown that people with a history of radiation exposure may have a greater risk of developing breast cancer than the average population, similar to those people with a BRCA mutation.

How much would a bilateral prophylactic mastectomy lower my risk of breast cancer?

Based on current evidence, a prophylactic mastectomy decreases the risk of developing breast cancer by at least 90%. This specifically applies to people with a BRCA mutation and those with a strong family history of breast cancer. Less research has been done on people with a history of radiation exposure, but BPM likely lowers their cancer risk, too. 

It’s important to note that BPM doesn’t completely eliminate someone’s risk of developing breast cancer. This is because there may be a small amount of breast tissue left behind after the procedure — such as in the armpit, on the chest wall, around the collarbone, or near the abdomen. It’s not possible to remove all of it completely. 

But studies show that developing breast cancer after BPM is very rare — it occurs in less than 1% of people who undergo this procedure.

Risks of a prophylactic mastectomy

BPM is a surgical procedure that does come with its own risks. These should be considered in the decision-making process, and include: 

• Surgical complications, such as pain, bleeding, infection, and complications of anesthesia

• Complications of breast reconstruction if this procedure is chosen, including future issues with implants or changes in appearance of the breasts

• Loss of nipple sensation and numbness of the breasts, which can have an effect on sexual arousal

• Inability to breastfeed 

• Scarring of the surgical area, which may be permanent 

• Effects on body image and dissatisfaction with appearance

• Potential psychological toll of the procedure

The importance and level of these risks is different for everyone. Your healthcare provider can help you understand how these factors affect your individual decision. But it may help to know that most people who undergo BPM express continued satisfaction with their decision in the long term.

What are my options if I don’t want a prophylactic mastectomy?

A prophylactic mastectomy is an individual decision. And there are other options if you are at high risk of breast cancer and choose not to have surgery. These include:

• More frequent screenings for breast cancer, with mammograms and/or breast MRIs regularly starting at a younger age than is typical for the general population 

• Certain medications that can help lower breast cancer risk, such as tamoxifen

Your healthcare provider can help you choose the best option for breast cancer screening and prevention if you have a high risk of developing breast cancer.

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Written by:

Joanna Jan, MD

Joanna Jan, MD, is board-certified in internal medicine and licensed to practice medicine in the state of Pennsylvania. In 2017, she received her board certification from the American Board of Internal Medicine.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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