In 2004, one in 10 American women under the age of 45 with cancer in one breast opted to have the second, healthy breast removed as well. Just eight years later, it had increased to one in three women, according to a study published Wednesday in JAMA Surgery. When looking at breast cancer patients of all ages in 2012, only 13% opted to have the healthy breast removed with the cancerous one; but that's still a major increase from 4.5% in 2004. The New York Times reports there's no evidence that removing a healthy breast will reduce a person's chances of dying from breast cancer in the future. In fact, the American Board of Internal Medicine and the American Society of Breast Surgeons recommend against it. So, it's unclear why breast cancer patients are increasingly choosing to go that route.
Ahmedin Jemal, senior author of the study, tells CNN it may be for symmetry or because of the widespread coverage of Angelina Jolie's choice to have both breasts removed. Or maybe patients just don't believe doctors when they say removing a healthy breast doesn't significantly reduce their risk of developing breast cancer a second time. Jemal also says there was a "very striking"—and unexplained—geographical difference in the number of women choosing to have a healthy breast removed, Reuters reports. The highest rates were seen in five contiguous states in the Midwest; the lowest in Hawaii. (Meanwhile, a report found the number of women diagnosed with breast cancer could double by 2030.)