While actresses Angelina Jolie and Rita Wilson recently disclosed that they both underwent a bilateral mastectomy, each had a very different reason for seeking out the procedure.

As Foxnews.com reports, in Jolie’s case, she underwent a preventative double mastectomy after a test determined that she carried a mutation in the BRCA1 gene, putting her at a high risk for developing breast cancer. Wilson’s decision came after a diagnosis of invasive lobular carcinoma, which was discovered after two surgical breast biopsies. However, the procedure for both women required the same medical surgery.

“A mastectomy is the removal of the breast tissue, and frequently the nipple, but not always,” Dr. Susan K. Boolbol, chief of breast surgery at Mount Sinai Beth Israel in New York City, told FoxNews.com. “It typically involves an overnight stay as it frequently involves reconstruction of the breast.”

How a woman may land on the decision to seek a mastectomy or bilateral mastectomy— removal of tissue from both breasts— is multifactorial, Boolbol said.

“With a diagnosis of breast cancer, the most common surgical procedure on the breast is a lumpectomy, where the area of cancer in the breast is removed, but the breast is left intact,” Boolbol said.

The other option for patients would be to undergo a complete mastectomy. Medically, the procedure relates to the characteristics of the cancer itself, Boolbol said, such as the size of it, where it is located, if there are several different areas of cancer, the size of the breast and the size of the breast relative to the size of the cancer.

For women who select to undergo a preventative mastectomy, the decision is a personal one.

“If you don’t medically need to have one but choose to, it’s usually based on your life experience,” Boolbol said, which can include watching others battle the disease. “Primarily it’s fear driven and it’s a way that women can gain some control over this and try to reduce the risk of a future problem.”

Boolbol noted that women with a genetic mutation of the BRCA1 or BRCA2 gene, like Jolie, frequently choose to undergo a bilateral mastectomy because their risk of developing breast cancer is much higher than the average woman.