The researchers followed 143 women in the United Kingdom whose doctors or genetic counselors had determined they were at high risk for developing breast cancer because of family history or the results of genetic testing. Of these women, 79 chose to have the surgery and 64 declined.

The women were surveyed and interviewed before surgery (or before declining surgery) and again 18 months later. The majority of women who had the surgery reported having reduced anxiety and no negative impact on their sexual or psychological well-being. In contrast, the high-risk women who did not have the surgery continued to have a high degree of anxiety about developing breast cancer.

"We saw very little postoperative regret," says study co-author Lesley Fallowfield, DSc, DPhil, a professor of psycho-oncology at University College in London. "Most of the women seemed absolutely certain they had done the right thing."

Women who said they had no regrets about their decisions had some things in common, she adds. For example, they often had younger children than the women who declined surgery, which may mean they acted out of concern about living to see their children grow up. In many cases, their own mothers had died of breast cancer when they were young, Fallowfield says.

The women who declined the surgery "tended to be people who adopted a more detached style of coping, try not to think about it, head-in-the-sand approach," she says. "The women who opted for the surgery were more problem-focused, and saw doing something as the best way to approach a problem."

But the study raises concerns that some women who opt for surgery may be overestimating their breast cancer risk, the researcher says. The women had gotten professional advice about their risks, which were one in two or one in four, compared to the one in 12 rate for the overall population of U.K. women. Those who chose surgery felt it was inevitable they would develop breast cancer if they did not have a mastectomy. They also had more investigative tests done before surgery than the women who declined it, according to Fallowfield.

Still, they often based the certainty that they would eventually develop breast cancer on non-scientific reasons. "These women felt it was inevitable they were going to get breast cancer, because they looked like their mum, or all the maternal aunts had died of this," Fallowfield says.

Debbie Saslow, PhD, director for breast and cervical cancer control for the American Cancer Society (ACS), says this study confirms other research conducted on this relatively small population of women. Less than 10% of all breast cancer cases are believed to involve genetic mutations that can be detected.

Saslow says it comes as no surprise that these women would have no regrets about mastectomy. "These are women who probably spent years fearing breast cancer," she says. "It's possible that [before surgery] their breasts prevented sexual pleasure. They may have been perceived as the enemy."

Women should know that preventive mastectomy should be considered only after competent genetic counseling with a professional who is familiar with adult-onset diseases, Saslow adds. To make a truly informed decision, she says, women should talk with a genetic counselor, even if they decide not to have genetic testing.

For more information about genetic testing, call 1-800-ACS-2345 or email the ACS.