Why Angelina Jolie Had Breast Removal Surgery

Actress Angelina Jolie has undergone a preventive double mastectomy, she revealed Tuesday in The New York Times.

She wrote an opinion piece, titled "My Medical Choice," explaining that she underwent the breast removal procedure because she has a mutated BRCA1 gene known to raise a woman's risk of breast and ovarian cancers.

The BRCA1 and BRCA2 genes work in the body to keep DNA stable and to make sure cells don't grow out of control, according to the National Cancer Institute. But certainmutations of these genes can dramatically raise cancer risk.

Jolie, 37, explained her risks from BRCA1 in the piece:

My doctors estimated that I had an 87 percent risk of breast cancer and a 50 percent risk of ovarian cancer, although the risk is different in the case of each woman.

Only a fraction of breast cancers result from an inherited gene mutation. Those with a defect in BRCA1 have a 65 percent risk of getting it, on average.

Jolie began the process on Feb. 2, when she underwent a "nipple delay" procedure to make sure there is no breast cancer behind the nipple. She completed all the mastectomy procedures on April 27, including breast reconstruction with an implant, she wrote.

"I wanted to write this to tell other women that the decision to have a mastectomy was not easy," she wrote. "But it is one I am very happy that I made. My chances of developing breast cancer have dropped from 87 percent to under 5 percent. I can tell my children that they don’t need to fear they will lose me to breast cancer."