Angelina Jolie Pitt underwent preventative surgery to remove her ovaries and fallopian tubes, according to the Op-Ed in the New York Times today that the actress, director and United Nations envoy wrote. 

Two years ago, Jolie Pitt elected to have a preventative double mastectomy after learning that she had a mutation in the BRCA1 gene, a gene that codes for tumor-suppressing proteins, which normally repair damaged DNA.

"When someone has a harmful mutation in that gene, it no longer allows the cell to repair itself, and then the cells can go awry and become cancerous," said Dr. Marleen Meyers, the director of the Survivorship Program at the New York University Perlmutter Cancer Center, who was not involved with Jolie Pitt's medical care. [5 Things Women Should Know About Ovarian Cancer]

Breast and ovarian cancer are more prevalent among women with the harmful BRCA1 mutation. About 12 percent of women in the general population develop breast cancer, but up to 65 percent of women with a BRCA1 mutation develop the disease by age 70, according to the National Cancer Institute.

Likewise, about 1.4 percent of women in the general population develop ovarian cancer, but about 39 percent of women with a BRCA1 mutation develop it by the time they're 70 years old, the NCI reports.

What's more, Jolie Pitt's mother died of breast cancer at age 56, and the actress' aunt and grandmother also died of cancer, giving her a strong family history of the disorder, according to Jolie Pitt.

But she was aware of the risk, she writes. After her mastectomy, Jolie Pitt continued to get checked for ovarian cancer. One test she had monitored her levels of CA-125, a protein that tends to increase in women with ovarian cancer. But that test isn't very sensitive, and shouldn't be used by itself to detect early ovarian cancer, Meyers told Live Science.

"It's not a very good screening tool," Meyers said. "I appreciate that she was having it, but it's more a tool that's used once someone has ovarian cancer and they're getting treatment. Then it can be used to follow the progress of the treatment."

However, Jolie Pitt's doctors were also screening her levels of other inflammatory cells and proteins. These markers were elevated and possibly a sign of early cancer, her doctors told her.

It's likely that these markers were similar to CA-125, but are better at picking up earlier stages of ovarian cancer, Meyers said. Research into these markers is still in its early stages, but the results look promising so far, she said.

After a series of body imaging tests, including a CT and a PET, and a tumor test, Jolie Pitt learned that she did not have cancer. But she realized that it could still develop at any time, and her doctors helped her decide that removing her ovaries and fallopian tubes was a good option for her.

"To my relief, I still had the option of removing my ovaries and fallopian tubes and I chose to do it," Jolie Pitt wrote in today's (March 24) Op-Ed.

However, Jolie Pitt still has an increased risk of cancer. A harmful BRCA1 mutation can increase the risk of other cancers, such as colon cancer and melanoma. And the body also has ovarian-type cells in the abdomen, which can also become cancerous, Meyers said.

Jolie Pitt is "incredibly courageous," for sharing her experience, Meyers said. "I think it was being proactive and I think it's putting a beautiful face on genetic testing." It also brings attention to menopause, which Jolie Pitt will go through now that her ovaries are gone.

There was a surge in the number of women who requested preventative double mastectomies after Jolie Pitt made her first announcement in 2013, Meyers said. Women with the BRCA1 gene who are considering removing their fallopian tubes and ovaries can take Jolie Pitt's experience into account, but Meyers advised that women do what is best for their bodies, as surgery can carry risks of complications and infections.

"In women who carry the gene, it's a reasonable thing to consider and talk about, but it's still a decision that needs to be made one-on-one" with a doctor, Meyers said.

Copyright 2015 LiveScience, a Purch company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.