Following a breast cancer diagnosis, many women opt for removal of both breasts, called a double mastectomy. But new research from the University of Michigan Comprehensive Cancer Center suggests around 70% of women do so, even though they face a very low risk of cancer in the healthy breast.

The researchers, led by associate professor Sarah Hawley, publish their findings in JAMA Surgery.

According to the American Cancer Society, 235,030 individuals in the US will be diagnosed with breast cancer this year and 40,430 will die from the disease.

The team notes that women with a family history of breast or ovarian cancer, or with mutations in the BRCA1 or BRCA2 genes, are typically advised to consider a double mastectomy since they have a higher risk of developing cancer in the healthy breast.

However, only around 10% of all women diagnosed with breast cancer fall into this category; the other women are unlikely to develop a second cancer in the other breast.

Because recent studies have shown that women are increasingly opting for this surgery, the researchers say the question of whether such patients are receiving overtreatment is valid.

To further investigate, they assessed 1,447 women who had been treated for breast cancer and had not had a recurrence.

In total, they found that 8% of the women had a double mastectomy and 18% considered it.

Surgeons should be aware of how patient worry affects decision-making

Of the study participants, around 75% reported that they were very worried about their cancer recurring, and those who opted for a double mastectomy were much more likely to report concern about recurrence.

However, the researchers point out that being diagnosed with cancer in one breast does not increase the likelihood of it occurring in the other breast for most women.

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Double mastectomy surgeries carry greater risks and complications for the patient than breast-conserving lumpectomy.

"Women appear to be using worry over cancer recurrence to choose contralateral prophylactic mastectomy," says Hawley. "This does not make sense, because having a non-affected breast removed will not reduce the risk of recurrence in the affected breast."

After assessing family history of breast and ovarian cancer and any genetic testing results, the researchers found that among the women who had both breasts removed, around 70% did not have a family history or a positive genetic test.

Many of these women, however, could have received breast-conserving lumpectomy, which is a smaller operation with fewer complications and an easier recovery.

Of the women who received a double mastectomy, most also had breast reconstruction, and women who need to undergo chemotherapy or radiation therapy after their surgery could have prolonged recoveries.

Interestingly, women with higher levels of education and those who underwent an MRI test prior to surgery were more likely to opt for having both breasts removed, with concern over recurrence being the biggest factor in deciding to have the surgery.

Hawley notes, however:


"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."

The team says that, while it is important to educate women about risks and benefits of surgery to remove both breasts, surgeons should also be aware of how a patient's worry over recurrence could affect her decision.

Medical News Today recently reported on a new blood test that researchers say accurately predicts breast cancer recurrence.