Prophylactic mastectomy: Breast cancer prevention for high-risk women
Prophylactic mastectomy: Breast cancer prevention for high-risk women
Prophylactic mastectomy may reduce your risk of breast cancer. Learn how doctors assess breast cancer risk and how a mastectomy might help prevent this disease.
By Mayo Clinic staff

Finding out you're at high risk of breast cancer forces you to confront questions few women are ever prepared to face. One such question is whether to have prophylactic (preventive) mastectomy — surgery to remove one or both breasts in hopes of preventing or reducing your risk of breast cancer.

As you begin to think about prophylactic mastectomy, keep this in mind: Being identified as high risk doesn't mean you'll get cancer. All it means is that, due to such factors as your family and personal medical history and your genetic makeup, your likelihood of developing breast cancer is several times higher than that of an average-risk woman. Understanding your individual level of risk will help you better appreciate risk-reducing strategies, including but not limited to prophylactic mastectomy.

Why choose prophylactic mastectomy: Risks and prevention

The truth is that all women are at risk of breast cancer just by being female and advancing in age. But some characteristics increase your risk significantly and make you a candidate for prophylactic mastectomy. You may consider this option if you have:

Already had cancer in one breast. If you develop breast cancer and have a strong family history of the disease, you may decide to have both breasts removed. One breast is removed to get rid of the cancer, and the other, unaffected breast is removed to greatly reduce the possibility of developing another breast cancer in your lifetime.
A family history of breast cancer. If you have two or more close family members — mother, sister, daughter, aunt, grandmother — who have had breast cancer before age 50 or during their premenopausal years, you have a significant family history of breast cancer. A predisposition to breast cancer can be passed on to you through your mother's or father's side of the family. If you have a family history of the disease, prophylactic mastectomy can reduce your chance of developing the disease by about 90 percent.
Positive results from gene testing. Genes are the blueprints that determine how your body grows and functions. Genetic testing can identify if you have mutations (alterations) in genes that increase your risk of breast cancer or other cancers such as ovarian and colon cancer. If genetic testing has shown that you have a mutation in genes associated with breast cancer (BRCA1 or BRCA2), you have a 40 percent to 85 percent chance of developing breast cancer by age 70. A prophylactic mastectomy to remove both breasts can significantly reduce that risk.
Early signs of cancer in your breast. Your doctor may have discovered precancerous or abnormal cells in the milk-producing glands (lobules) of your breast (lobular carcinoma in situ). These findings are not cancers, but are markers of an increased risk of developing breast cancer over your lifetime.
Your doctor determines whether you're at high risk of breast cancer based on these factors and on mathematical models that calculate the risk of carrying a gene mutation.

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 all of your options. Many breast centers are staffed with breast-health specialists, genetic counselors, breast surgeons and reconstructive surgeons who will collaborate with you.

Thankfully, the decision to have or forgo prophylactic mastectomy is not urgent. Give yourself time to sort out your feelings and weigh the pros and cons of the procedure. Women typically spend six months to a year or even several years between first considering prophylactic mastectomy and saying yes or no. You may want to discuss your concerns and feelings with a psychologist.

Though a prophylactic mastectomy reduces your risk of breast cancer, it doesn't guarantee that you will never develop the disease. Breast tissue is widely distributed on your chest wall. Sometimes it 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 mastectomy. Breast tissue remaining in your body can still develop breast cancer, although the chances are slim.

The majority of women who undergo prophylactic mastectomy are satisfied with their choice. Those who decide to have surgery mainly because their doctors advise them to may be more likely to express regret afterwards.

Prophylactic mastectomy: Breast cancer prevention for high-risk women
Deciding against surgery
If you're at high risk of breast cancer and you decide against prophylactic mastectomy, you do have other options:

Surveillance. The goal of surveillance is to detect any possible cancer at its earliest stage. If you have positive results from gene testing, your doctor may recommend you do a breast self-exam every month beginning in your early 20s. Your doctor may also recommend clinical breast exams once or twice a year beginning in your mid-20s. Annual mammograms may be recommended when you're 25 to 35.

If you have a family history of breast cancer that doesn't seem related to a mutation in BRCA1 or BRCA2, your doctor may recommend that you begin annual mammograms by age 40, or about five to 10 years before the age at which your youngest affected first-degree relative was diagnosed with breast cancer (whichever comes first). For example, if your mother had breast cancer at 40, you'd start your mammograms at 30 or 35.

Women who carry the BRCA 1 or 2 gene or are at very high risk are being offered annual breast MRI screening in addition to mammography to screen for breast cancer.

Chemoprevention. In this approach, you prevent breast cancer by taking drugs that block the effects of estrogen. Tamoxifen (Nolvadex), the first drug used for this purpose, has long been prescribed to prevent breast-cancer recurrence in women who have already been treated for estrogen-receptor positive cancer. More recently, a similar drug — raloxifene (Evista) — was approved for preventing invasive breast cancer in postmenopausal women at high risk of developing the disease. Both drugs have been shown to reduce the risk of invasive breast cancer by approximately 50 percent.
A difficult decision
Only women with a high risk of developing breast cancer are candidates for prophylactic mastectomy, and the decision can be difficult to make. Researching your options and talking with your doctor can give you the information you need to decide whether prophylactic mastectomy is right for you.

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