The procedure to remove both breasts is called contralateral (the corresponding part on the opposite side) prophylactic (preventative) mastectomy. Women choose prophylactic mastectomy to reduce their risk of, and their fear that, they will develop cancer in their other breast. In fact, between 1998 and 2003, the rate of prophylactic mastectomies more than doubled. This comes at a time when many younger women are developing aggressive forms of breast cancer.

Women with breast cancer have the highest risk of developing cancer again. Ten out of every 100 women will develop cancer in the other breast within 10 years (this increases for women with other risk factors). Prophylactic mastectomies reduce the incidence of breast cancer by as much as 90 percent. However, researchers point out this doesn't necessarily mean these women will live longer. Removing both breasts does not eliminate the risk of breast cancer; it just reduces it.

Although experts are evaluating the medical benefits of prophylactic mastectomies, there are many confounding factors, such as a woman's specific treatment, that muddy the waters. Perhaps the most interesting study (reported in the journal Cancer, March 2009), found that removing the breast that was not being treated for cancer in fact just removed cancer that was already present but not yet detected, implying that this procedure is more than just a preventative measure.

Breast cancer advocates are concerned about the rise in double mastectomies. They point to less invasive ways to reduce the risk of breast cancer recurrence. However, 10 years after having a preventative mastectomy, most women report being satisfied with their decision.

With such confusing data, how do you decide if this procedure is right for you?

Experts say that certain women are more likely to benefit from contralateral prophylactic mastectomy. This includes women who:

  • Are at higher risk due to family history or other factors,
  • Had invasive lobular breast cancer (less common) rather than invasive ductal breast cancer (more common),
  • Had breast cancer in more than one location, and
  • Younger women with early stage, hormone receptor-negative disease.

The medical benefits of prophylactic mastectomy are less certain for women who are not genetically at risk for breast cancer. If you have breast cancer, discuss all the treatment options with your physician before making any decisions.