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  • Komen Perspectives - Why are rates of bilateral mastectomies rising? (May 2010)

    Many women diagnosed with early breast cancer have a choice between lumpectomy or mastectomy for their surgery. While a lumpectomy removes the tumor and some surrounding tissue, a mastectomy removes the entire breast. Although the chance of cancer recurrence within the breast is higher with a lumpectomy, the overall chances of survival are the same for both procedures. 

    A unilateral mastectomy is the removal of one breast and a bilateral mastectomy is the removal of both breasts.  A woman may get a bilateral mastectomy if she has cancer in both breasts. Or, a woman may choose a bilateral mastectomy when she has cancer only in one breast and chooses to have the opposite, healthy breast removed.  The procedure to remove the healthy breast is called a contralateral (opposite breast) prophylactic (preventive) mastectomy (CPM).  When a woman chooses CPM, both breasts are removed during the surgery: the breast that contains cancer (mastectomy) and the opposite, healthy breast (CPM).  For reasons we don’t fully understand, rates of CPM are on the rise.1 Between 1998 and 2003, rates of CPM in the United States more than doubled from 1.8 to 4.5 percent.1 And, among women having a mastectomy instead of lumpectomy, the rate of CPM increased from 4.2 to 11.0 percent.1 Women choosing CPM tend to be younger, Caucasian and have a higher educational level.1-4  While there are many reasons a woman might choose CPM, the surgery has its own risks.  Also, the health benefits of CPM are unclear.  Hence, the unexpected increase in rates of CPM has caused concern among some in the medical community. 

    CPM greatly lowers the risk of developing cancer in the healthy breast, but it does not appear to increase overall survival and is not routinely recommended.1. The National Comprehensive Cancer Network (NCCN) guidelines discourage CPM for most women and recommend that it only be considered on a case-by-case basis for women at high risk of breast cancer, such as those who carry a BRCA1 or BRCA2 mutation or those with Li-Fraumeni syndrome who have a higher risk of contralateral breast cancer.5 Few women fall into this category (only 5-10 percent of breast cancer cases are related to a genetic mutation).6  

    Among women who do not carry a genetic mutation, the NCCN does not recommend CPM because the risk of developing cancer in the healthy breast is fairly low. Between 3 and 9 percent of these women who choose lumpectomy or unilateral mastectomy (removal of only the breast containing cancer) will go on to develop breast cancer in the opposite breast.7,8  

    Although CPM does not appear to improve survival, it gives some women peace of mind.7 Some women have fears of developing breast cancer in the remaining, healthy breast. These fears may be compounded by high levels of stress and anxiety related to future breast cancer screening of the remaining breast. However, many women may overestimate their risk of getting cancer in their healthy breast, and a better understanding of this risk may help overcome some fear and anxiety. Doctors may also overestimate the risk of a contralateral breast cancer.9 And, a doctor’s recommendation to have a CPM can be an important factor in a woman’s decision to have CPM.1,2  

    Other women may choose CPM so that reconstructive breast surgery occurs on both breasts at the same time with the hope that this will improve the chances of a symmetrical look.  However, newer reconstruction techniques can make the affected breast look quite similar to the natural, healthy breast and reconstruction on both breasts after CPM may not always achieve a better result. 

    Increasing use of magnetic resonance imaging (MRI) before breast cancer surgery may also play a role in the increase in rates of CPM.3,10 Ten years ago, fewer than 10 percent of patients had MRI before surgery.2 In recent years, studies have reported rates between 14 and 51 percent.2-5,9 Women who have a pre-operative MRI may be nearly twice as likely to choose a CPM.3 

    Sometimes, an MRI can show more detail of a tumor or other potentially suspicious areas. These findings may change the surgical choice of the doctor or a woman’s personal choice for surgery.3 Unfortunately, MRI has a high rate of false positives. A false positive occurs when something appears to be cancer on the MRI, but turns out to be benign (not cancer). An abnormal finding on an MRI can be distressing, even when a biopsy shows that the finding was not cancer. This anxiety can impact the decision to have a more extensive surgery.10  

    There seem to be multiple reasons for the rise in CPM. If women are choosing this option to ease fears of recurrence, CPM may improve their quality of life. However, beyond peace of mind, the health benefits of CPM are unclear. Thus, if other factors are influencing women to have CPM, then they need to be explored. This topic is actively under study and future findings will help us to understand the additional reasons behind the growing trend of use of CPM. 

    Commentary from Eric P. Winer, MD, Susan G. Komen for the Cure®’s Chief Scientific Advisor

    As discussed in the article above, rates of bilateral mastectomies are on the rise.  For most women, this involves a mastectomy for cancer on one side, and a prophylactic mastectomy of the other breast.  For a small number of women, bilateral mastectomies are performed because of cancer in both breasts.  There are situations in which bilateral mastectomies are necessary.   However, there are many settings in which the decision to proceed with bilateral mastectomies is based upon unfounded fear or an inaccurate assessment of the risks and benefits that a woman may face.  As with all medical decisions, women should discuss the pros and cons of their health care choices with their treatment team, and they should seek a second opinion if they are uncertain about the best approach.  The decision to have bilateral mastectomies should not be made without considerable thought.  In my view, women should proceed cautiously and think carefully about the advantages and disadvantages of the medical choices involved. 


    1. Tuttle TM, Habermann EB, Grund EH, Morris TJ, Virnig BA. Increasing use of contralateral prophylactic mastectomy for breast cancer patients: a trend toward more aggressive surgical treatment. J Clin Oncol. 25(33):5203-9, 2007. 

    2. Jones NB, Wilson J, Kotur L, Stephens J, Farrar WB, Agnese DM. Contralateral prophylactic mastectomy for unilateral breast cancer: an increasing trend at a single institution. Ann Surg Oncol. 16(10):2691-6, 2009. 

    3. Sorbero ME, Dick AW, Beckjord EB, Ahrendt G. Diagnostic breast magnetic resonance imaging and contralateral prophylactic mastectomy. Ann Surg Oncol. 16(6):1597-605, 2009. 

    4. Arrington AK, Jarosek SL, Virnig BA, Habermann EB, Tuttle TM. Patient and surgeon characteristics associated with increased use of contralateral prophylactic mastectomy in patients with breast cancer. Ann Surg Oncol. 16(10):2697-704, 2009. 

    5. National Comprehensive Cancer Network. Updated NCCN guidelines for breast cancer discourages prophylactic mastectomy in women other than those at high risk.  http://www.nccn.org/about/news/newsinfo.asp?NewsID=226, 2009. 

    6. National Cancer Institute. Genetics of breast and ovarian cancer. http://www.cancer.gov/cancertopics/pdq/genetics/breast-and-ovarian/HealthProfessional/page3, 2010. 

    7. Yi M, Meric-Bernstam F, Middleton LP, et al. Predictors of contralateral breast cancer in patients with unilateral breast cancer undergoing contralateral prophylactic mastectomy. Cancer. 115(5):962-71, 2009. 

    8. Alkner S, Bendahl PO, Fernö M, Nordenskjöld B, Rydén L for the South Swedish and South-East Swedish Breast Cancer Groups. Tamoxifen reduces the risk of contralateral breast cancer in premenopausal women: Results from a controlled randomised trial. Eur J Cancer. 45(14):2496-502, 2009.

    9. Wood WC. Should the use of contralateral prophylactic mastectomy be increasing as it is? Breast. 18 Suppl 3:S93-5, 2009. 

    10. Bilimoria KY, Cambic A, Hansen NM, Bethke KP. Evaluating the impact of preoperative breast magnetic resonance imaging on the surgical management of newly diagnosed breast cancers. Arch Surg. 142(5):441-5, 2007.