Study: More patients with invasive breast cancer opting for double mastectomies

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Women diagnosed with invasive breast cancer have a number of surgical options. They can have breast-conserving surgery (lumpectomy) with radiation, a unilateral (single) mastectomy to remove only the tissue from the cancerous breast, or a contralateral prophylactic mastectomy (CPM), which removes both breasts. A new study finds that more women are opting for CPM, yet overall survival for these patients is not increasing. (5/3/2016)


At a glance In-depth
Findings     Limitations               
Guidelines Resources and references
Questions for your doctor  


This study is about:

Whether invasive breast cancer patients who elect to have contralateral prophylactic mastectomy (risk-reducing removal of a woman’s healthy breast when her opposite breast has breast cancer) have increased survival compared to women who have breast-conserving surgery (lumpectomy) with radiation or mastectomy only in the treated breast.

Why is this study important? Contralateral prophylactic mastectomy is an invasive surgical procedure that puts women at risk for complications such as infection. After diagnosis, some women are at high risk for a second breast cancer due to an inherited mutation in BRCA or another gene that increases breast cancer risk. However, according to the study authors, “the majority of women undergoing CPM are at low risk for developing a contralateral breast cancer.” Study authors reasoned that women who already have a low risk for a second breast cancer are unlikely to see a survival benefit by removing their healthy breast.

Study findings: 

  1. CPM among women with invasive breast cancer has increased significantly, from about 4% in 2002 to about 13% in 2012.
  2. No significant improvement was found in breast cancer-specific survival or overall survival between women who had CPM compared to women who had breast-conserving surgery (lumpectomy) with radiation.

What does this mean for me?

Although CPM does not reduce the risk for dying of cancer, it does reduce the chance of a second breast cancer diagnosis, especially in high-risk women. This is particularly true for women with BRCA, other cancer-causing mutation, or a strong family history of cancer. In this study, researchers focused on survival, but women also choose CPM for other reasons. The decision on risk-reducing mastectomy is highly personal. Discuss all your options with your health care providers to decide which procedure is best for you.

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Expert Guidelines

The American Society of Breast Surgeons (ASBrS) develops practice guidelines for breast surgery.

ASBRrS recommendations for contralateral prophylactic mastectomy (CPM):

ASBrS convened a panel of experts to develop guidelines on contralateral mastectomy. The ASBrS recommended the following: 

CPM should be considered for those at significant risk of CBC

  • Documented BRCA1/2 carrier.
  • Strong family history, but patient has not undergone genetic testing.
  • History of mantle chest radiation before age 30 years.

CPM can be considered for those at lower risk of CBC

  • Gene carrier of non-BRCA gene (e.g., CHEK-2, PALB2, p53, CDH1).
  • Strong family history, patient BRCA negative, no known BRCA family member.

CPM may be considered for other reasons

  • To limit contralateral breast surveillance (dense breasts, failed surveillance, recall fatigue).
  • To improve reconstructed breast symmetry.
  • To manage risk aversion.
  • To manage extreme anxiety. (This may be better managed through psychological support strategies.)

CPM should be discouraged

  • Average-risk woman with unilateral breast cancer.
  • Women with advanced index cancer (e.g., inflammatory breast cancer, T4 or N3 disease, stage IV disease).
  • Women at high risk for surgical complications (e.g., patients with comorbidities: obesity, smoker, diabetes).
  • Woman tested BRCA negative with a family of BRCA-positive carriers.
  • Male breast cancer, including BRCA carriers.

These guidelines are up to date as of 10/10/19. 


Questions To Ask Your Health Care Provider

  • What is my risk of developing cancer in my other breast?
  • What complications may occur if I undergo contralateral prophylactic mastectomy?
  • I have invasive breast cancer; what are all of my options?
  • I have been diagnosed with breast cancer before age 45. Should I consider genetic testing before I make decisions about surgery?
  • I do not have a BRCA mutation, but I have a very strong family history of breast cancer. Should I consider contralateral prophylactic mastectomy?
  • I have a BRCA mutation, but I would like to avoid mastectomy. What are my risks for a second breast cancer?


Study background:

Women with genetic mutations in BRCA and other genes associated with increased cancer risk, and women with a strong family history of breast or ovarian cancer benefit from contralateral prophylactic mastectomy (CPM) because they have a higher risk for a second breast cancer. However, these women represent less than one-third of women who choose CPM. Studies show that about 80%-98% of women who choose CPM do so because they want to prevent cancer in their other breast, yet the majority of women who choose CPM are at low risk of developing a second breast cancer.  

In March 2016, Stephanie Wong and colleagues from the Harvard School of Public Health and other institutions published a study in Annals of Surgery that looked at the increasing rate of CPM, and assessed if it correlated to an improvement in survival.

Researchers of this study wanted to know:  

Do increases in contralateral prophylactic mastectomy rates in women with invasive breast cancer result in longer survival for these patients?

Population(s) looked at in the study:

This study used data from the SEER (Surveillance, Epidemiology, and End Results) database, including 494,488 women who had stages 1, 2 or 3 unilateral breast cancer and were diagnosed between 1998 and 2012.

Study Findings:

  1. The number of women with invasive breast cancer who chose contralateral prophylactic mastectomy (CPM) between 2002 and 2012 significantly increased, from about 4% in 2002 to about 13% in 2012.
  2. The increase in breast reconstruction after CPM also increased, from about 35% in 2002 and to about 55% in 2012.
  3. No significant improvement in estimated breast cancer-specific survival or overall survival was identified between women who had CPM compared to women who had breast-conservation (lumpectomy) with radiation.
  4. Even when HR (hormone receptor) status (positive or negative) and age were factored in, the researchers still did not see any benefit in breast cancer-specific survival or overall survival.


This study used previously collected information from women through the SEER database—research using databases such as SEER is useful in designing controlled studies, which compare how different treatment options affect survival. Because the researchers did not collect the data themselves, they did not have all information about these women, such as their risk factors (genetic information, family history, other medical issues), socioeconomic status, or other potentially pertinent factors. The researchers also did not know the HER2 receptor status of these patients (positive or negative), procedure preference of their surgeons, or what treatments these women had.


This study suggests that in general, CPM provides no survival benefit in most women with invasive breast cancer. Additionally, a study done by Alison Kurian and colleagues from Stanford University and other institutions found similar results in Californian women, where “use of bilateral mastectomy increased significantly throughout California from 1998 through 2011, and was not associated with lower mortality than that achieved with breast-conserving surgery plus radiation.” However, they did find that women who underwent unilateral mastectomy had higher mortality than women who underwent bilateral mastectomy or breast-conserving surgery plus radiation.

It is important to remember that there are groups of women—carriers of BRCA or other mutations and women with a strong family history of breast cancer—who do see a survival benefit from CPM. Women have different reasons for choosing or not choosing CPM; survival is one reason but other reasons are equally valid. Ultimately, women should speak with their health care provider to make sure they understand the risks and benefits of CPM, and to determine what plan of action is most appropriate for them.

Posted May 3, 2016

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