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.
Sept. 29, 2016 See more In-depth