Experts say several intersecting factors could be fueling this trend.

Access to genetic screening

Since testing became available in 1996, nearly 1 million people have been screened for BRCA1 and BRCA2, the genetic mutations associated with increasing a woman's lifetime risk of developing breast cancer as much as 87 percent, according to Myriad Genetics, the diagnostic company that helped isolate the two genes and later developed a test to detect them.

For women who test positive, removing both breasts is seen as a viable, cancer-preventing option -- especially in the United States.

In a global study conducted by Dr. Steven Narod, senior scientist at Women's College Research Institute in Toronto, the United States had the highest rate of prophylactic mastectomy in BRCA1 and BRCA2 mutation carriers. The U.S. rate was 36.3 percent, far outpacing the number of preventive surgeries performed by the majority of other countries Narod studied, including France and Canada.

One reason for the spike may be that American women fear cancer more than women in other regions. About 70 percent of women in the United States who have both breasts removed after a cancer diagnosis don't have a proven medical reason for undergoing the procedure, according to a 2012 study conducted by the University of Michigan Comprehensive Cancer Center.

"The dilemma we're facing is more and more women are choosing to remove both breasts," said Dr. Michael Sabel, associate professor of surgery at the University of Michigan Medical School, in a statement announcing the findings. "We're greatly overestimating the risk of women with breast cancer developing another breast cancer."

However, authors of the study indicate that a double mastectomy may make sense for women with a strong family history of breast or ovarian cancer, or for women who've tested positive for genetic mutations in the BRCA genes.

Dr. Susan Domchek, executive director of the Basser Research Center for BRCA at the University of Pennsylvania, said the escalating rate is linked to easy access of information.

"The data we've been collecting is evolving quickly, and these women are living with this information in real time," she said in an email. "Since 1994 enormous progress had occurred: (T)he genes have been cloned, clinically available tests for gene mutations have been developed, and the implications of having BRCA1/2 mutations are better understood. Women as young as 25 are using this data to make informed choices."