安吉丽娜·朱莉进行双乳切除术

Actress and activist Angelina Jolie has revealed she has had a preventive double mastectomy to reduce her risk of developing breast cancer. Health campaigners praised her decision to go public with the news, which she said was prompted by a desire to encourage other women to get gene-tested and to raise awareness of the options available to those at risk.

A leading lady in Hollywood -- Angelina Jolie has used her star power to promote humanitarian causes .

Now she is taking on another cause -- breast health.

Writing in the Newyork Times, Jolie says she underwent a double mastectomy after learning she tested positive for one of the breast cancer genes.

"She’s in her 30’s and she has several children and she watched her mother die from cancer, and she wants to do the most she can to avoid this." said Dr. Judy Garber from Dana Farber Cancer Institute

Genetic mutations cause five to ten percent of breast cancers.

Getting tested for the genes is the most effective way to determine your risk -- but doctors say only people with a strong family history should consider screening.

"If it looks like there’s a lot of breast and ovarian cancer, particularly in young women in your family, seek the advice of a high risk clinic. Inquire about the possibility of having a BRCA test done." Said Dr. Isabelle Bedrosian, md Anderson Cancer Center.

While the test is widely available -- not every woman can afford the hundreds of dollars in out-of-pocket expenses.

"Genetic testing is covered by most insurers in the US at this time - not ever as completely as one would like -- it is still a very expensive test." said Dr. Judy.

 So are the treatment options for women who test positive -- which include breast and ovary removal surgeries -- or vigilant monitoring with mammograms and breast m-r-is.

Neither option is a one hundred percent guarantee -- but they do significantly lower the risk for disease.