A small but growing number of women with a type of early breast cancer are choosing to have their healthy breasts removed to prevent the chance of recurrence, according to a study from the University of Minnesota.

The vast majority of women with the early cancer, known as ductal carcinoma in situ (DCIS), choose lumpectomies to remove only the cancerous tissue.

But the number opting for double mastectomies in the same circumstances rose from 2.1 percent to 5.2 percent between 1998 and 2005, a 148 percent increase, the study found.

Dr. Todd Tuttle, a cancer surgeon who led the study, said the extra surgery probably isn't necessary in most such cases.

"I don't think anyone believes that removing the opposite breast for someone who has DCIS is going to improve upon their already good survival rate," he said.

The 10-year survival rate is now 98 to 99 percent with any type of treatment, he said.

Tuttle said many women are choosing extra surgery for psychological or cosmetic reasons, rather than medical ones.

"The main reasons are probably that women don't want to go through it again," he said. They'd rather get it over with, and have reconstructive surgery, than live in fear. Tuttle said he found a similar trend in a 2007 study of women with more advanced breast cancer.

In some cases, he said, women worry about their appearance if they have surgery on one side. "A lot of women want to have double mastectomies because they believe they can get a better cosmetic outcome," he said. But he noted that reconstructive surgery is riskier and requires far more recovery time than a simple lumpectomy, which can be done as an outpatient procedure.

Tuttle said he usually recommends a lumpectomy for women with DCIS, unless they're at high risk for recurrence.