The number of women choosing this option has nearly doubled in the past few years alone. Overall in 2006, ~6% of women choose to have this done along with the affected breast, and continuing to grow. Among younger women (less than 40 years of age), statistics show that 1:10 women choose this option in a recent study out of the University of Minnesota. This option is chosen even moreso in women who have the in situ type, as shown in a recent publication in the Journal of Clinical Oncology. It rose dramatically from 2.1% of women in 1998 to 5.2% of women in 2005 alone.
Clearly, women with a genetic risk for breast CA lower her chance of ultimately developing a cancer with this preventative measure. However, studies have shown that performing a mastectomy on an "unaffected" breast does not improve the odds of survival. Several studies have reported this recently. There was a small survival benefit in a certain subgroup of women: less than 50 years of age, early-stage, estrogen-receptor (-) tumors without response to Tamoxifen.
The highest risk to women is not from a future cancer, but from the potential spread of that cancer that is already present. So, removing the opposite breast would not have any effect on changing these odds. Women are certainly opting for the above procedure not because of the statistics, but, for the psychological benefit of not wanting to re-experience the trauma of mammogram/biopsy/diagnosis/etc. The fear has been averted (theoretically) by bilateral mastectomy. This is a reasonable option for every woman, and one which should be discussed with the woman so that she can make an informed decision. Most importantly, it is the individual woman's choice.
