Double Mastectomy May Not Decrease Risk of Death From Cancer

Nurse Assisting Patient Undergoing Mammogram

Double mastectomy, or surgery where both breasts are removed, has become a mainstay of treatment for certain types of breast cancer. Surgeons have increasingly used the procedure to remove both breasts when a cancer in one is suspected of being a sign of cancer or risk of cancer in the other. The idea is to prevent another cancer from appearing in the other breast that might be in a stage beyond treatment. A new study out this week suggests that this practice might be flawed.

The study looked at almost 190,000 women who underwent some sort of surgery for breast cancer. Surgeries included double mastectomy, unilateral mastectomy or breast-conserving surgery where the tumor is removed and surrounding tissue dosed with radiation. Researchers looked at cases over the span of 13 years from 1998 to 2011 and looked at how often the procedures were done over time and how many women died in each group.

They found a dramatic rise in the number of women treated with double mastectomy, especially in younger women under 40 who saw double mastectomy go from 5% of surgeries to about 40% of surgeries for breast tumors. This occurred in spite of the fact that no significant data supported the use of double mastectomy as more effective than other treatments. This increase in double mastectomy came at the cost of sometimes dramatic reductions in the number of breast-conserving surgeries, in spite of the fact that these types of surgeries have been found in some cases to be more effective than removing the entire breast in a unilateral mastectomy.

When the researchers looked at mortality, or the number of deaths seen in each group, they found that unilateral mastectomy came with the highest risk of death, followed by bilateral mastectomy and breast-conserving surgery, which carried the same risk of death. While the removal of both breasts may seem like the best way to prevent cancer spread, recurrence, or new cancer in the future, the data showed that removing just the tumor and following up with radiation therapy is just as good.

The research isn’t indicating that double mastectomies and unilateral mastectomies should never be done. Each cancer is different and each patient will have different preferences about how treatment should proceed. What this research reminds us is that more radical and invasive is not necessarily better. It’s tempting to think that if removal of the tumor is good, removal of the breast is better and removal of both breasts is best. We now know that’s often not the case.

The dramatic rise in the use of the procedure in spite of little evidence for its effectiveness in preventing death puzzled researchers, who hypothesized that often decisions about removing these tumors are made based on the emotional fear of recurrence that may not reflect the actual risk. As a result, many women may be undergoing more drastic procedures to protect against a risk that is lower than they realize.

The authors say they hope these findings encourage a more critical analysis of the options available when surgeons and patients are deciding the best course of action. Finding the best surgery for a woman with a particular cancer will hopefully shift with the data to one that will both maximize the length and quality of her life.