Sarah Hawley, Ph.D., found that worry often outweighs statistics when choosing breast cancer treatment.

Snap judgment

Most women who have double mastectomy have no clinical indications

issue 22 | Fall 2014

About 70 percent of women who have contralateral prophylactic mastectomy following a breast cancer diagnosis do so despite a very low risk of facing cancer in the healthy breast, new research from the University of Michigan Comprehensive Cancer Center finds.

Recent studies have shown an increase in women with breast cancer choosing this more aggressive surgery, which raises the question of potential overtreatment among these patients.

The study authors looked at 1,447 women who had been treated for breast cancer and who had not had a recurrence. They found that 8 percent of women had a double mastectomy, and that 18 percent considered having one. Results appear in JAMA Surgery.

Nearly 70 percent of women receiving a double mastectomy did not have any clinical indications.

Overall, about three-quarters of patients reported being very worried about their cancer recurring. Those who chose to have double mastectomy were significantly more likely to express concern about recurrence.

"Women appear to be using worry over cancer recurrence to choose contralateral prophylactic mastectomy. This does not make sense, because having a non-affected breast removed will not reduce the risk of recurrence in the affected breast for most women," says Sarah Hawley, Ph.D., associate professor of Internal Medicine at the U-M Medical School.

In addition to asking about the type of treatment, researchers asked about clinical indications for double mastectomy. Women with a family history of breast or ovarian cancer or with a positive genetic test for mutations in the BRCA1 or BRCA2 genes may be advised to consider contralateral prophylactic mastectomy due to a high risk of a new cancer developing in the other breast. This represents about 10 percent of all women diagnosed with breast cancer.

The study found that among women receiving a double mastectomy, nearly 70 percent did not have any clinical indications and many were candidates for breast-conserving lumpectomy.

"For women who do not have a strong family history or a genetic finding, we would argue it's probably not appropriate to get the unaffected breast removed," Hawley says.

A double mastectomy is a bigger operation that is associated with more complications and a more difficult recovery. In addition, most women went on to have breast reconstruction as well. Women might also still need to undergo chemotherapy or radiation therapy after their surgery — treatments that are known to reduce the risk of cancer recurring — which could delay their recovery further.

The researchers say it's important to educate women better about the risks and benefits of contralateral prophylactic mastectomy, but that surgeons must also be aware of how patients' worry about recurrence drives their decision-making.