WEDNESDAY, March 29, 2017 (HealthDay News) -- In certain areas of the United States, more women diagnosed with early stage breast cancer are choosing to have the unaffected breast removed, new research finds.
The study also found that younger women are especially likely to have the second breast removed.
Nearly half of women under age 45 diagnosed with early breast cancer in five states opted for the procedure, said the study's senior author, Dr. Ahmedin Jemal. He's vice president of the American Cancer Society's Surveillance and Health Services Research Program.
The five states are Colorado, Iowa, Missouri, Nebraska and South Dakota.
The study included records from 1.2 million women from 45 states and Washington, D.C. All patients were 20 and older. All had been diagnosed with early stage breast cancer in one breast and were treated with surgery between 2004 and 2012.
Between those years, the proportion of patients who had the opposite healthy breast removed as a preventive measure increased from under 4 percent to more than 10 percent among women ages 45 and older. It increased from more than 10 percent to more than 33 percent in those women ages 20 to 44.
The increase was evident in all states, but varied widely depending on the state. For instance, in Virginia, the rate tripled during the study period -- from under 10 percent to more than 32 percent. In New Jersey, the rate went from 15 percent to 25 percent, the study showed.
Jemal said he can't explain the geographic variation.
At first, the researchers thought women might be opting for the additional surgery to ensure symmetry of the breasts after reconstructive surgery on the breast with cancer. Yet, investigators didn't find a correlation between the procedure on the healthy breast and the rates of reconstruction on the breast with cancer.
Another possibility, Jemal said, is the "Angelina Jolie effect." He was referring to the actress who chose surgical removal of both her breasts when she was found to have the BRCA gene mutation, which increases the risk of breast cancer.
The decision is extremely personal, experts concur. However, for the average-risk woman, the evidence doesn't support having the healthy breast removed, Jemal said.
"There is no evidence it improves survival" for the average-risk woman diagnosed with early stage breast cancer, he said.
Previous research has shown the risk of developing cancer in the opposite breast is 2 to 6 percent over 10 years, Jemal said. In other words, he said, "94 to 98 percent don't have a cancer in the opposite breast over the next 10 years."
Even so, fear may be a driving force, Jemal said. But, he noted the study didn't look at what triggered women's decisions.
The findings were published online March 29 in JAMA Surgery.
The strong regional differences are noteworthy and offer new information, said Dr. Lisa Newman, who wrote an editorial to accompany the study. She's director of the breast oncology program at the Henry Ford Health System in Detroit.
Newman advised women: "Have a frank discussion with your surgeon[s] so that you clearly understand whether or not you are eligible for breast-saving lumpectomy surgery to treat the known cancer.
"If you are a candidate for breast conservation, then there is no reason to commit prematurely to unilateral or bilateral mastectomy, since these surgical options do not provide any survival advantage," Newman explained.
"If you are not a candidate for lumpectomy surgery [either because of the extent of your cancer or because you are not able to receive the radiation that typically accompanies lumpectomy surgery], then it is important to review your breast reconstruction options," she said.
Having the healthy breast removed may sometimes offer some reconstruction advantages, but it doesn't offer a survival advantage, Newman said.
Newman said removing the healthy breast opens the door to complications.
"We as physicians must ensure that [patients] understand that the more extensive surgery has a higher complication rate; that it is risk-reducing but not risk-eliminating; and that it does not improve likelihood of curative treatment for the initially diagnosed breast cancer," she said.
To learn more about breast surgery, visit the U.S. National Cancer Institute.