Many breast cancer patients wrongly believe that having both breasts removed — a double mastectomy — will improve their chance of survival, a new study has found.

“Our finding that so many women are receiving much more extensive surgery than needed to treat their disease is striking,” said study lead author Dr. Reshma Jagsi, associate professor of radiation oncology at the University of Michigan Medical School in Ann Arbor.

Researchers surveyed more than 1,900 women treated for breast cancer and found that nearly half of them had considered having a double mastectomy.

Many who had the more aggressive surgery had no risk factors, such as family history of breast cancer, that would increase their odds for cancer in the second breast.

“Women diagnosed with breast cancer are naturally eager to do everything in their power to fight the disease.

“So many of my patients tell me that they just want to do everything they can to be there for their kids,” Dr. Jagsi explained.

“It is up to us, as doctors, to make sure they understand which treatments are really going to do that, and which actions might seem heroic but are actually not expected to improve the outcomes for a typical woman.”