Having prophylactic mastectomy is a very personal choice. There is no "right answer", only what you consider is best for you.
Women who are at high risk of developing breast cancer have the option of prophylactic (preventive) mastectomy as a way of decreasing their risk.
Factors that increase a woman’s chance of developing breast cancer include
a genetic predisposition to breast cancer e.g. BRCA+, Cowden's Syndrome, Li-Fraumeni Syndrome
a strong family history of breast cancer
a breast cancer diagnosis at a young age
abnormal breast cells on biopsy that increase the risk of breast cancer, e.g. LCIS
a history of previous chest radiation, e.g. treatment for Hodgkin's Lymphoma
Prophylactic mastectomy decreases the risk of future breast cancer by 97-99%. Since the breast tissue is removed, the surgery also removes the need for regular screening mammograms/MRIs and preventive drugs like tamoxifen.
Surgery is not the only option however. Many women prefer close monitoring and preventive drugs (known as "chemoprophylaxis").
Regardless of other choices, all women should modify their diet wherever possible to decrease their risk. It is vital you discuss all your options and the pros, cons, and risks of each before making the best decision for you.
You have several reconstructive options and the results can be very natural and cosmetic.
If you choose to undergo breast reconstruction at the same time, a "skin-sparing" mastectomy is usually performed. This saves all the breast skin envelope which significantly adds to the cosmetic results without increasing your risk of cancer. In many cases, the nipple-areola can be saved too. This is known as a "nipple-sparing" mastectomy .
Thankfully, most insurance plans cover the cost of prophylactic mastectomy and reconstruction in high risk patients but you will have to check with your individual plan to make 100% sure.