No Guarantees

Last November, Rachel Meiser, a 33-year-old nurse, learned that she had a cancerous lump in her right breast. Just a few months earlier, she had tested positive for a rare genetic mutation called CDH1, placing her at a high risk of developing breast cancer, which killed her grandmother, and stomach cancer, which killed her father.

So in January, Meiser had both her breasts removed, even though only one was cancerous. Given her genes and family history, her doctor advised her to get the double mastectomy, and she agreed "absolutely," she says: "You either do it and go on with your life, or you don't, and you risk the possibility of dying."

Like Meiser and, more recently, actress Christina Applegate, a small but growing number of women with cancer in only one breast are opting to get their healthy breast removed too. In a study published in the Journal of Clinical Oncology last October, researchers found that the rate of bilateral mastectomies among women with cancer in only one breast more than doubled from 1998 to 2003, from 1.8 percent to 4.8 percent. "The main motivation is fear," says Stephen Sener, a doctor and former president of the American Cancer Society. "Some women say, 'I can't live with the anxiety of having this happen again'."

For many women, a double mastectomy alleviates some of the concern about becoming one of the more than 40,000 U.S. women who die from breast cancer each year. A 2005 study in the Journal of Clinical Oncology found that a decade after the procedure, 83 percent of patients were satisfied or very satisfied with their choice. "A lot of women really feel that it's liberating," says Jocelyn Dunn, a breast surgeon in Palo Alto, Calif. "Regrets are rare."

Many of those who choose to get prophylactic mastectomies of healthy breasts are young women, like Meiser and Applegate, who don't want to worry about recurrence or frequent testing. Applegate, 36, told ABC on Aug. 19 that once she looked at her options, the choice she made was the "one that seemed the most logical."

But the decision isn't always that straightforward. Not everyone has the resources that a celebrity does to take time off from work for recovery or to pay what can be substantial out-of-pocket reconstruction costs. And for women who don't have the gene that predisposes them to breast cancer, the medical benefits are less than certain. (Only 5 to 10 percent of women diagnosed with breast cancer have a hereditary form of the disease.)

Prophylactic mastectomies do reduce the incidence of breast cancer by as much as 90 percent, but studies have not yet shown that that means women who get them will live any longer than those who don't. "Fewer women are choosing to have just one breast removed," says Todd Tuttle, chief of surgical oncology at the University of Minnesota and lead author of the Journal of Clinical Oncology article. "[But] if they believe it's going to improve their survival rate, then we've got a problem."

Some women simply overestimate the risk of getting cancer in the opposite breast. The typical patient has about .5 percent to .75 percent risk per year of developing a new cancer in the healthy breast, which works out to a 20 to 30 percent chance of developing a new cancer by age 80 if she is treated and diagnosed at age 40, says Seema Khan, co-leader of the breast cancer program at the Robert H. Lurie Comprehensive Cancer Center at Northwestern University.