Women facing an early-stage breast cancer diagnosis may elect to have a contralateral prophylactic mastectomy (CPM) to reduce the risk of developing a contralateral breast cancer. In the United States, CPM rates for all surgically treated women with stages I through III unilateral breast cancer increased dramatically from 1998 to 2003. In 1991, the National Institutes of Health Consensus Panel concluded that breast-conserving surgery is an appropriate and preferred treatment for the majority of women with stage I and II breast cancer because it provides survival rates equivalent to those of total mastectomy while preserving the breast. Owing to the near equivalence of the 2 surgical treatment options in terms of survival benefit and recurrence risk, surgical treatment for early-stage breast cancer qualifies as a “preference-sensitive decision” for which no one treatment is best (S. T. Hawley, 2010; The Dartmouth Atlas of Health Care, 2010). We performed a literature review to identify studies that examined CPM decision making in women facing an early-stage breast cancer diagnosis with the aim of determining the most influential factors affecting her surgical choice. Study outcome measures were largely based on demographic information retrospectively extracted from large databases representing trends rather than revealing influences reflecting preference-sensitive decision making. While we may know demographically, which women choose CPM, we do not know why. To better understand this increasing trend, which greatly impacts patient counseling, prospective research is needed using decision quality methods developed to illuminate factors influencing a woman's decision.