(CBSNews.com) - Angelina Jolie's decision to have a double mastectomy in order to lower her chances of developing breast cancer has put the topic of women preemptively removing their breasts in order to avoid the disease in the spotlight. But experts are concerned that many women may have gotten the wrong message -- and opted for surgery that won't really help them.
About 232,340 women will get breast cancer in 2013, according to government statistics. Almost 40,000 women will die this year from the disease.
Jolie explained in a New York Times op-ed last May that she had a strong familial history of cancer, and that genetic testing indicated her risk of developing breast cancer was 87 percent. The actress also added that she had a 50 chance of developing ovarian cancer, and would opt to have her ovaries removed at a later date.
"Once I knew that this was my reality, I decided to be proactive and to minimize the risk as much I could," she wrote. "I made a decision to have a preventive double mastectomy. I started with the breasts, as my risk of breast cancer is higher than my risk of ovarian cancer, and the surgery is more complex."
It's a decision that many women with breast cancer in one breast also choose to make. An increasing number opt to have the healthy, unaffected breast removed in a procedure called a contralateral prophylactic mastectomy (CPM) to prevent the disease from spreading. In the 1990s, about 4% to 6% of women who got a mastectomy opted to have the other breast removed as well; in more recent years, researchers estimate the rate has tripled or even quadrupled.
But researchers behind an Annals of Internal Medicine study published on Sept. 17 say the evidence shows CPM does little to improve survival rates for most women -- and that many who choose to undergo the surgery actually overestimated their risk of dying from breast cancer.
For the survey, researchers talked to 123 women aged 40 or younger who were diagnosed with cancer in one breast but opted to get both breasts removed. Most of the women had stage 1 or stage 2 cancer, and 60 percent of their tumors were estrogen receptor-positive, meaning the tumors grew more in the presence of estrogen.
The vast majority -- 98 percent -- said that they had both breasts removed because they wanted to decrease their risk of cancer spreading to the other breast. Ninety-four percent of the women also said they believed removing the healthy breast would give them a better chance at overall survival, and 95 percent said the procedure would give them "peace of mind."
However, almost all the women overestimated their actual risk of getting cancer in the other breast.
An accompanying editorial in the Annals of Internal Medicine states that doctors need to find a better way to share existing studies and statistics about cancer risks and the benefits and downsides of CPM to help patients decide whether they want the procedure. The authors found it concerning that many women knew CPM wouldn't help their survival, but chose to go through with the procedure anyway for those reasons.
Women in the survey said that their doctors were their most important sources of information when it came to learning about breast cancer, but only one-third said that following their doctor's recommendation was the reason behind their decision to have CPM.
Ninety percent of the women said they did not regret their decision and would do it again. Still, many did point out that the outcomes of the surgery were worse than they were expecting. Thirty-three percent said they underestimated the number of procedures and surgeries they would need, and 28 percent said they didn't expect the numbness or tingling in the chest they experienced.
"Additional clarification of conficting responses -- specifically, the inconsistencies between the importance of improved survival as a reason for choosing CPM and the acknowledgment that CPM is not associated with better survival outcome -- would be helpful," the authors of the study wrote. The editorial suggested there is a "teachable opportunity" for doctors to help their patients make informed decisions based on accurate data.
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