Bilateral prophylactic mastectomy has been shown to reduce the risk of breast cancer by at least 95 percent in women who have a deleterious (disease-causing) mutation in the BRCA1 gene or the BRCA2 gene and by up to 90 percent in women who have a strong family history of breast cancer (2-5).
https://www.cancer.gov/types/breast/risk-reducing-surgery-fact-sheet
If you're having both breasts removed (double mastectomy), expect to spend more time in surgery and possibly more time in the hospital. If you're having breast reconstruction following mastectomy, the procedure also takes longer and you may stay in the hospital for a few additional days.
http://www.mayoclinic.org/tests-procedures/mastectomy/basics/what-you-can-expect/PRC-20012749
Mastectomy may be the right choice for you if the following is true for you: 1  If the tumor is larger than 5 centimeters, you will probably need a mastectomy. 2  If your breast is small and a lumpectomy would leave you with very little breast tissue, your doctor may advise you to have a mastectomy.
http://www.breastcancer.org/treatment/surgery/mastectomy/who_for
Double mastectomy. If a mastectomy is done on both breasts, it is called a double (or bilateral) mastectomy. When this is done, it is often as preventive surgery for women at very high risk for getting cancer in the other breast, such as those with a BRCA gene mutation.
https://www.cancer.org/cancer/breast-cancer/treatment/surgery-for-breast-cancer/mastectomy.html
Mastectomy is a way of treating breast cancer by removing the entire breast through surgery. It’s often done when a woman cannot be treated with breast-conserving surgery (lumpectomy), which spares most of the breast. It can also be done if a woman chooses mastectomy over breast-conserving surgery for personal reasons.
https://www.cancer.org/cancer/breast-cancer/treatment/surgery-for-breast-cancer/mastectomy.html
If no cancer is present, no further lymph nodes need be removed. If cancer is present, the surgeon will discuss options, such as radiation to your armpit. If this is what you decide to do, no further lymph nodes will need to be removed. The different types of mastectomy are: Modified radical mastectomy.
http://www.mayoclinic.org/tests-procedures/mastectomy/basics/what-you-can-expect/PRC-20012749
Regardless of the type of mastectomy you have, some breast tissue and lymph nodes will be sent to a laboratory for analysis. If you're having breast reconstruction at the same time as mastectomy, the plastic surgeon will coordinate with the breast surgeon to be available at the time of surgery.
http://www.mayoclinic.org/tests-procedures/mastectomy/basics/what-you-can-expect/PRC-20012749
Prophylactic surgery to remove a contralateral breast during breast cancer surgery (known as contralateral prophylactic mastectomy) reduces the risk of breast cancer in that breast (2,4,5,13), although it is not yet known whether this risk reduction translates into longer survival for the patient (13).
https://www.cancer.gov/types/breast/risk-reducing-surgery-fact-sheet
However, total mastectomy provides the greatest breast cancer risk reduction because more breast tissue is removed in this procedure than in a subcutaneous mastectomy (1). Even with total mastectomy, not all breast tissue that may be at risk of becoming cancerous in the future can be removed.
https://www.cancer.gov/types/breast/risk-reducing-surgery-fact-sheet
Mastectomy may be the right choice for you if the following is true for you: 1  If the tumor is larger than 5 centimeters, you will probably need a mastectomy. Depending on stage and other factors, some tumors smaller than 5 centimeters may still require mastectomy, although others may be addressed by lumpectomy.
http://www.breastcancer.org/treatment/surgery/mastectomy/who_for
when to do double mastectomy
If a mastectomy is done on both breasts, it is called a double or bilateral mastectomy.