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

Prophylactic mastectomy reduces the risk of developing breast cancer by 90 percent in high-risk women. That means, for every 100 women with a high risk of breast cancer that undergo prophylactic mastectomy, 90 of those women will never be diagnosed with breast cancer. Ten women can be expected to develop breast cancer after the surgery.

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 surgery. Sometimes breast tissue can be found in your armpit, above your collarbone or on the upper part of your abdominal wall, where it may not be detected at the time of your surgery. Breast tissue remaining in your body can still develop breast cancer, although the chances are slim.

What are the risks?

As is true with any surgery, prophylactic mastectomy comes with potential complications, including:

  • Bleeding
  • Infection
  • Pain
  • Development of scar tissue
  • Anxiety or disappointment about changes to your appearance

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 do have other options for early detection and risk reduction:

  • Breast cancer screening. The goal of surveillance is to detect cancer at its earliest stage. Screening recommendations vary, and your doctor may suggest a screening schedule based on your individual situation. The American Cancer Society recommends that women at high risk get a mammogram and magnetic resonance imaging (MRI) every year beginning at age 30. Screening may also involve a clinical breast exam by your doctor and breast self-exams you can do on your own.
  • Medications to reduce risk. In this approach, you may reduce your risk of breast cancer by taking drugs that block the effects of estrogen, because estrogen can promote breast cancer development and growth. Medications used for this purpose include tamoxifen, raloxifene (Evista) and, in certain cases, exemestane (Aromasin). These drugs may reduce the risk of invasive breast cancer by approximately 50 percent. However, they carry a risk of side effects. Talk with your doctor about the risks and benefits of these medications.
  • Surgery to remove the ovaries. Prophylactic oophorectomy can reduce the risk of both breast cancer and ovarian cancer. Women with BRCA mutations also have an increased risk of ovarian cancer. Prophylactic oophorectomy may reduce the risk of breast cancer up to 50 percent in women with a high risk of breast cancer.
  • Healthy lifestyle changes. Healthy lifestyle changes, such as 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. But it's not clear how much these changes can reduce the risk for women with an already high risk of breast cancer. Discuss these healthy lifestyle changes with your doctor to better understand how they might impact your breast cancer risk when combined with other risk-reduction strategies.
Dec. 22, 2011 See more In-depth