Women with breast cancer caused by BRCA gene have a much better survival chance if they have both breasts removed instead of one, a study said, Newsmax Health reports.

Out of 100 women with a BRCA gene mutation who have a double mastectomy for early breast cancer, 87 will be alive after 20 years

This compares to 66 of every 100 who opt for a single amputation, according to the research published in the British Medical Journal (BMJ).

"We conclude that it is reasonable to propose bilateral mastectomy as the initial treatment option for women with early-stage breast cancer who are carriers of a BRCA1 or BRCA2 mutation," the authors wrote.

The mastectomy question was thrown into the spotlight last year when Hollywood star Angelina Jolie announced she had both breasts surgically removed as a preventative measure after tests revealed she carried the BRCA mutation. She had not been diagnosed with the disease.

Rocker Ozzy Osbourne's wife, Sharon, did the same the previous year.

For the study, specialists in Canada and the United States compared the survival rates of 390 women diagnosed with early-stage breast cancer between 1975 and 2009.

They were all known carriers or likely carriers of a mutation in the BRCA1 or BRCA2 gene.

Of the group, 79 women died in the follow-up period -- 18 of them had had a double mastectomy and 61 a single one.

 "Having both breasts removed was associated with a significant (48 percent) reduction in breast cancer death compared with having only one breast removed over a 20 year period," said a statement.

Analyzing the results of a 25-year Canadian study with nearly 90,000 women, researchers said mammograms were no more effective at preventing cancer deaths than physical breast examination.