Fear drives most women to undergo double mastectomy following cancer diagnosis in one of the breasts. They opt for the surgery - Contralateral Prophylactic Mastectomy (CPM) - despite low risk of developing cancer in the healthy breast, according to a University of Michigan study.

A double mastectomy is associated with more complications and a difficult recovery. Even after surgery, women need chemotherapy or radiation - which lowers the risk of recurrence of cancer, but could delay the recovery process.

For the study, researchers observed 1,447 women with breast cancer, who had not had a recurrence.

They found that 8 percent of the women underwent a double mastectomy and 18 percent of them had thought of having one. Overall, about three-quarters of participants were frightened about cancer recurrence. Those who had both their breasts removed were more distressed about the cancer's reappearance than women who considered the surgery or did not have it at all.

"Women appear to be using worry over cancer recurrence to choose contra-lateral 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," said Sarah Hawley, Ph.D., associate professor of internal medicine at the U-M Medical School, in a press release.

Researchers said that the diagnosis of cancer in one of the breasts does not necessarily lead to the occurrence of the disease in the other one. Women - who have a family history of breast cancer, ovarian cancer or with a positive genetic test for mutations in the BRCA1 or BRCA2 genes - are generally recommended to have both their breasts removed. Women without these symptoms are not likely to develop cancer in the healthy breast.

In the study, nearly 70 percent of the women, who went through the surgery, were neither identified with a family history nor positive genetic test. Many of these women were ideal 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," said Hawley.

The study also found that highly-educated women and those who had undergone an MRI test before surgery were more likely to opt for double mastectomy.

Researchers said that educating women about the risks and benefits of CPM is important. Surgeons must also consider the patient's concerns about recurrence in decision-making.

The finding is published in JAMA Surgery.