Most Women Who Choose Double Mastectomy Don't Need To, Study Shows

Worry about recurrence drives decision, experts say, but majority have low risk of cancer in the healthy breast

By Kathleen Doheny
HealthDay Reporter

TUESDAY, Nov. 27 (HealthDay News) -- Almost 70 percent of women with breast cancer who choose to have both breasts removed as a precaution actually have a low risk of developing cancer in the healthy breast, a new study finds.

Worry about recurrence -- which is understandable -- typically drives the decision to have the opposite breast removed, said study author Dr. Sarah Hawley, an associate professor of internal medicine at the University of Michigan Health System in Ann Arbor. The procedure is called a contralateral prophylactic mastectomy (CPM).

However, that worry can be out of proportion to actual risk, she said. "Our point is that worry about recurrence probably should not drive choice for CPM since this procedure will not reduce the risk of cancer recurrence; it is only going to reduce the risk of developing a new primary in the non-affected breast," she said.

The risk of a new cancer in the healthy breast is less than 1 percent for most women, Hawley explained, while the risk of cancer coming back in the same breast or nearby lymph nodes is 8 percent.

Hawley's team surveyed nearly 1,500 women who had been treated for breast cancer and had not had a recurrence after four years. Of those, 35 percent had considered CPM and 7 percent had the surgery to remove both breasts. When they looked only at the women who had a mastectomy to treat their cancer, nearly one in five chose to have both breasts removed.

Yet, 70 percent of the women who underwent CPM actually had a very low risk of developing breast cancer in the healthy breast.

Hawley is scheduled to present the findings Friday at the American Society of Clinical Oncology's Quality Care Symposium, in San Diego.

The CPM procedure has been increasingly requested by women with breast cancer in recent years. "The downsides of CPM are the same as those for any surgical procedure," Hawley said. Among them are risks associated with surgery, extended recovery time and any psychosocial drawback to having both breasts removed.

Overall, the rate of women who underwent CPM was low, at 7 percent. But among those who had a mastectomy in the breast with cancer, 19 percent opted to have the other breast removed.