Many women get double mastectomy when only one breast has tumors

Women with cancer in one breast may opt to have both breasts removed even though a double mastectomy isn't always linked to better survival odds, a recent study suggests.

Researchers analyzed survey data from women with early-stage cancer in one breast and found 17 percent had both breasts surgically removed as part of treatment.

"For most women with breast cancer, who do not have an inherited genetic mutation that predisposes them to a high risk of cancer formation, the risk of developing a second breast cancer in the other breast is actually quite low," said lead study author Dr. Reshma Jagsi of the University of Michigan in Ann Arbor.

"Removing the other breast is an extremely aggressive approach with little benefit for most women with breast cancer," Jagsi added by email. "Yet most women tell us that they pursue this option for peace of mind; to me, this suggests that at least some women have not been fully informed."

Most women with breast cancer have some type of surgery - either a lumpectomy that removes malignant tissue while sparing the rest of the breast or a mastectomy that removes the entire breast. After surgery, many of them also receive chemotherapy to destroy any remaining abnormal cells and reduce the risk of cancer coming back.

A double mastectomy for cancer in one breast was rare a decade ago, but has become more common in recent years, Jagsi said.

Most women without an inherited genetic risk for aggressive malignancy are not likely to develop tumors in a second breast after cancer is detected in one breast. In fact, they're more likely to develop cancer in other parts of their body, rather than in the second breast, she noted.

For the study, researchers examined data collected in 2013 and 2014 from about 2,400 women with tumors in one breast.

Overall, 1,056 women, or 44 percent, considered a double mastectomy. Of these, 395 women, or less than half, knew that this course of treatment doesn't improve survival odds for all women with breast cancer, researchers report in JAMA Surgery.

Two-thirds of the study participants didn't have a high genetic risk for aggressive tumors, and 39 percent of these women said a surgeon had advised against a double mastectomy.

In the subset of women without a genetic risk or identified mutation that boosts the odds for aggressive tumors, 12 percent still had both breasts surgically removed

Among these lower-risk women, 19 percent of patients who weren't advised against a double mastectomy by doctors underwent the procedure.

This more aggressive surgical approach to breast cancer carries an increased risk of pain and complications, particularly if women also opt for reconstructive plastic surgery.

One limitation of the study is its reliance on women to accurately recall and report what they discussed with doctors before choosing a course of treatment, the authors note.

Still, the results highlight a need to balance any psychological benefit women may be getting from the peace of mind that comes with removing both breasts against the long term harms of an unnecessary operation, Dr. Shelley Hwang writes in an accompanying editorial.

In the United States, about one in 10 women with cancer in one breast decide to have the other breast removed as a preventive measure, Hwang, a researcher at Duke University Medical Center in Durham, North Carolina, said by email.

"This is a number that has been increasing significantly over the last 20 years," Hwang said.

"This trend has concerned many of us who have worried that women are making this decision based upon an inaccurate understanding of how much they may benefit by having this procedure," Hwang added. "The current study is important because it surveyed patients about how they made the decision to have the other breast removed, and indicates that better education of patients by their surgeons may help reverse this trend."