Researchers who studied 1,447 women treated for breast cancer found that 8 per cent of them had undergone a double mastectomy.
But 70 per cent of these women did not meet the medically approved criteria for losing both breasts - a family history of breast or ovarian cancer, or BRCA 1 or BRCA 2 gene mutations.
They had a very low risk of developing cancer in the healthy breast, the US scientists said.
Study leader Dr Sarah Hawley, from the University of Michigan, said: "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 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 research, published in the journal JAMA Surgery, also found that 18 per cent of the women studied had considered a double mastectomy.
The new research coincides with former Dancing With The Stars host Samantha Harris making public her decision to have a double mastectomy following a diagnosis of breast cancer.
She was praised by Baroness Delyth Morgan, chief executive of the Breast Cancer Campaign charity, for raising "awareness of the fact that breast cancer can occur at any age".