Preventive (prophylactic) mastectomy: Surgery to reduce breast cancer risk

Prophylactic mastectomy may reduce your risk of breast cancer. Learn how doctors assess breast cancer risk and how prophylactic mastectomy may help prevent breast cancer.

By Mayo Clinic Staff

Finding out you’re at high risk of breast cancer leads to difficult questions and decisions.

One such question is whether to have preventive mastectomy (prophylactic mastectomy) — surgery to remove one or both breasts in hopes of preventing or reducing your risk of breast cancer.

Keep in mind that being identified as high risk doesn’t mean you’re certain to get breast cancer. All it means is that your likelihood of developing the disease is several times higher than that of an average-risk woman.

Understanding your individual level of risk can help you weigh your options for risk-reducing strategies, including prophylactic mastectomy.

Who may consider prophylactic mastectomy to reduce breast cancer risk?

All women are at risk of breast cancer just by being female and advancing in age. But some factors increase your risk significantly.

You may consider prophylactic mastectomy if you have:

  • Already had cancer in one breast. If you need to have one breast removed because of a new cancer diagnosis, and you have a very high risk of cancer in the other breast, based on a strong family history or a genetic test, you may decide to have the other, unaffected breast removed at the same time. This prophylactic mastectomy reduces the possibility of another breast cancer in your lifetime, but doesn’t completely eliminate the risk.
  • A family history of breast cancer. If your mother, sister or daughter has had breast cancer, especially if she was diagnosed before age 50, you may be at increased risk. If you have multiple family members — on your mother’s or father’s side — with breast or ovarian cancer, your risk of breast cancer may be greater.
  • Positive results from gene testing. Genetic testing can identify mutations in genes, such as BRCA1 and BRCA2, that substantially increase your risk of breast or other cancers. If you have a strong family history of breast cancer, consider meeting with a genetic counselor to discuss genetic testing. Women who are of Ashkenazi Jewish descent have a higher incidence of the BRCA1 and BRCA2 mutations.
  • Breast changes that significantly increase your risk of cancer. Your doctor may have discovered abnormal cells in the milk-producing glands of your breast, a condition known as lobular carcinoma in situ (LCIS). LCIS isn’t cancer, but it’s a marker of an increased risk of developing cancer in both breasts. If you have a strong family history of breast cancer and a personal history of LCIS, chemoprevention or prophylactic mastectomy may be options to manage your risk.
  • Radiation therapy. If you had radiation therapy to your chest between the ages of 10 and 30, you have an increased risk of developing breast cancer.
  • Dense breasts. Dense breast tissue is associated with breast cancer. Dense breast tissue also makes it harder for doctors to diagnose breast cancer. A woman with dense breasts may consider a prophylactic mastectomy, especially if she has other risk factors, such as a strong family history of breast cancer or precancerous conditions.

Your doctor determines whether you’re at high risk of breast cancer based on your risk factors.

With whom should high-risk women discuss their options?

Deciding what to do with the knowledge that you are at high risk of breast cancer is a complex and time-consuming process. It’s best if you can work with a team of health professionals to get a complete evaluation of your risk and take the time to understand all of your options.

Many breast centers are staffed with breast-health specialists, genetic counselors, breast surgeons and reconstructive surgeons who can collaborate with you. Second opinions are strongly recommended for women considering prophylactic mastectomy.

Making the decision whether to have prophylactic mastectomy is not urgent. Give yourself time to weigh all the pros and cons. You may want to discuss your concerns and feelings with a breast-health specialist and psychologist.

How much does prophylactic mastectomy reduce the risk of breast cancer?

Prophylactic mastectomy can reduce the chances of developing breast cancer in women at high risk of the disease:

  • For women with the BRCA1 or BRCA2 mutation, prophylactic mastectomy reduces the risk of developing breast cancer by up to 90 percent.
  • For women who have already had breast cancer and also have a family history of the disease, prophylactic mastectomy can reduce the risk of developing cancer in the other breast by 90 to 95 percent.

However, studies indicate that prophylactic mastectomy has little or no effect on survival for women who have had breast cancer in one breast but who don’t have a strong family history of cancer or a genetic mutation. For these women with an average risk, prophylactic mastectomy may increase the risks of surgical complications without offering additional benefits, such as longer overall survival.

Having a prophylactic mastectomy doesn’t guarantee that you’ll never develop breast cancer because all of your breast tissue can’t be removed during the surgery. Sometimes breast tissue can be found in your chest, armpit or skin, above your collarbone, or on the upper part of your abdominal wall.

It is impossible for a surgeon to remove all of this breast tissue. Although the chances are slim, breast tissue remaining in your body can still develop breast cancer.

What are the risks?

As with any surgery, prophylactic mastectomy has potential complications, including:

  • Bleeding
  • Infection
  • Pain
  • Anxiety or disappointment about changes to your appearance
  • Complications arising from breast reconstruction
  • The need for multiple operations

Are there other options for reducing the risk of breast cancer?

If you’re at high risk of breast cancer and you decide against prophylactic mastectomy, you have other options for early detection and risk reduction.


Estrogens are hormones produced in your body that can promote breast cancer development and growth. Medications that block the effects of estrogen or reduce estrogen production in your body can reduce your risk of breast cancer. The options include:

  • Tamoxifen, for premenopausal or postmenopausal women
  • Raloxifene (Evista), for postmenopausal women
  • Exemestane (Aromasin), for postmenopausal women
  • Anastrozole (Arimidex), for postmenopausal women

Although these medications can reduce the risk of invasive breast cancer by about 50 percent, they carry a risk of side effects. Discuss the risks and benefits of these medications with your doctor and together you can decide whether medication is right for you.

Other options

Other options for early detection and risk reduction include:

  • Breast cancer screening. Your doctor may suggest mammogram and magnetic resonance imaging (MRI) every year. Screening should also involve an annual clinical breast exam by your doctor and breast-awareness education to familiarize you with normal consistency of your breast tissue.
  • Surgery to remove the ovaries (prophylactic oophorectomy). This procedure can reduce the risk of both breast and ovarian cancers. In women at high risk of breast cancer, prophylactic oophorectomy may reduce that risk by up to 50 percent if the procedure is done before age 50, when women are premenopausal.
  • Healthy lifestyle. Maintaining a healthy weight, exercising most days of the week, limiting alcohol use and avoiding hormone therapy during menopause may reduce the risk of breast cancer. However, there aren’t yet any conclusive studies showing that specific dietary changes reduce the risk of breast cancer.