BOSTON, March 14 (UPI) -- The number of women undergoing bilateral mastectomy to prevent breast cancer has tripled in the last decade, though researchers say they are unsure whether it has increased their chances of surviving the disease.
Although many women with breast cancer have chosen to have both breasts removed, rather than just the one with cancer, to reduce the risk of recurrence, data do not show whether lives have been saved with the preventive procedure.
Double mastectomies have become more common since Angelina Jolie opted for one in 2013, but were already on the rise as more women undergo genetic testing after breast cancer diagnosis.
More than 95 percent of women get tested for BRCA1 or BRCA2 mutations, with 86.4 percent of women who have a mutation opting for a double mastectomy, but a recent study also showed 51.2 percent of women without the mutation also have the procedure.
"Despite all the data [over decades] comparing women who underwent breast-conserving surgery and mastectomy and the survival was exactly the same, the rate of bilateral mastectomy is actually picking up and not slowing down," Dr. Mehra Golshan, a researcher of surgical oncology at Brigham and Women's Hospital, told CNN.
For the study, published in the Annals of Surgery, researchers identified 496,488 women in the Surveillance, Epidemiology and End Results registry diagnosed between 1998 and 2012 with stage 1 to stage 3 breast cancer, analyzing their surgical choice and improvement in cancer condition.
Of the women diagnosed with unilateral invasive breast cancer, 59.6 percent had breast-conserving surgery, 33.4 percent had unilateral mastectomy and 7 percent had a preventive double mastectomy. The proportion of women having double mastectomies has increased overall from 3.9 percent in 2002 to 12.7 percent in 2012.
The researchers found, despite the high rates of surgery, and increase in double mastectomies, that 10-year survival rates remained about the same for all three surgical groups at 91.8 percent for those having breast-conserving surgery, 83.8 percent for unilateral mastectomy and 90.3 percent for a double mastectomy.
"If I can say that the prophylactic mastectomy is going to keep you alive longer, then absolutely, that's something we should definitely strive for," Golshan told Time. "But it really made no difference in terms of overall outcome and survival."