Double mastectomies significantly lower risk of breast cancer in women who are genetically at risk

February 23, 2004

(Philadelphia, PA) - An international study led by researchers from the Abramson Cancer Center of the University of Pennsylvania has found that a prophylactic double mastectomy - surgical removal of both breasts to prevent a cancer before it occurs - can lower the risk of developing breast cancer by 90 percent in women genetically pre-disposed to the disease. This is the first study to quantify the risk reduction for this procedure and its impact on hundreds of thousands of women in the United States who carry mutations in one or both of the two genes - BRCA1 and BRCA2 - strongly linked to breast and ovarian cancer. Their findings appear in the March 15th edition of the Journal of Clinical Oncology.

"Women are still at risk for breast cancer after any kind of mastectomy as some breast tissue remains in the body after surgery," said lead author Timothy R. Rebbeck, PhD, Co-Program Leader of the Center's Cancer Epidemiology and Risk Reduction Program and an Associate Professor of Epidemiology at Penn's School of Medicine. "Now that we have quantified the benefit of a double mastectomy for reducing the chances of breast cancer, women in this high-risk group can make a better-informed decision about having breast surgery in addition to other forms of prevention, such as regular screening and/or other preventive surgeries, including ovary removal."

The study, called PROSE (Prevention and Observation of Surgical Endpoints), followed 483 at-risk women from 11 sites in the United States, Canada, United Kingdom and the Netherlands for over six years. Most of the North American women chose not to have preventive, or prophylactic, double mastectomies. Multiple study controls were used to guard against research bias. Women who chose to have prophylactic mastectomies were paired with women in a control group based on type of mutation, treatment center and year of birth within five years. In addition, none of the participants had any previous or current diagnosis of cancer upon entering the study.

Breast cancer was diagnosed in two of 105 women (1.9 percent) who had double mastectomies. The occurrence of breast cancer was much greater in the control group, with 184 of 378 women (48.7 percent) developing breast cancer.

"The goal of future research is to refine these estimates for women in specific situations: according to the type of BRCA mutation; type of mastectomy - different procedures remove varying amounts of breast tissue; and the age and timing of surgery - many women past their child-bearing years also choose removal of their ovaries at the same time as their breast surgery," said Rebbeck. "The decision to undergo genetic testing or have prophylactic breast surgery is a highly personal one that should be discussed with a clinician trained in counseling patients about the risks and benefits of each preventive option."

Study results also confirmed a large risk reduction for breast cancer (95 percent) for women who also had their ovaries removed. "Genetically pre-disposed women should also consider this procedure when evaluating their options for reducing their risk of breast cancer," said Rebbeck.

Funding for this study was provided through a research grant from the National Institute on Health, Penn's Abramson Cancer Center, the Breast Cancer Research Foundation, the Dana-Farber Women's Cancers Program, the US Department of Defense Breast Cancer Research Program, the Utah Cancer Registry, the Falk Medical Research Trust, the Utah State Department of Health, and the Nebraska State Cancer and Smoking-Related Diseases Research Program.

Close to 200,000 cases of breast cancer were diagnosed in the US in 2001. The lifetime risk of any particular woman getting breast cancer is about one in eight.

Between three and 10 percent of breast cancers may be related to mutations in the genes BRCA1 and BRCA2. Women can inherit these mutations from their parents, and it may be worth testing for either mutation if a woman has a particularly strong family history of breast cancer. If a woman is found to carry either mutation, she has a greatly increased chance of getting breast cancer before age 70.
Journal of Clinical Oncology

Editor's Note:
You may also find this news release on-line at

About the Abramson Cancer Center:
The Abramson Cancer Center of the University of Pennsylvania was established in 1973 as a center of excellence in cancer research, patient care, education and outreach. Today, the Abramson Cancer Center ranks as one of the nation's best in cancer care, according to US News and World Report, and is one of the top five in National Cancer Institute (NCI) funding. It is one of only 39 NCI-designated comprehensive cancer centers in the United States. Home to one of the largest clinical and research programs in the world, the Abramson Cancer Center of the University of Pennsylvania has 275 active cancer researchers and 250 Penn physicians involved in cancer prevention, diagnosis and treatment. More information about the Abramson Cancer Center is available at:

University of Pennsylvania School of Medicine

Related Breast Cancer Articles from Brightsurf:

Oncotarget: IGF2 expression in breast cancer tumors and in breast cancer cells
The Oncotarget authors propose that methylation of DVDMR represents a novel epigenetic biomarker that determines the levels of IGF2 protein expression in breast cancer.

Breast cancer: AI predicts which pre-malignant breast lesions will progress to advanced cancer
New research at Case Western Reserve University in Cleveland, Ohio, could help better determine which patients diagnosed with the pre-malignant breast cancer commonly as stage 0 are likely to progress to invasive breast cancer and therefore might benefit from additional therapy over and above surgery alone.

Partial breast irradiation effective treatment option for low-risk breast cancer
Partial breast irradiation produces similar long-term survival rates and risk for recurrence compared with whole breast irradiation for many women with low-risk, early stage breast cancer, according to new clinical data from a national clinical trial involving researchers from The Ohio State University Comprehensive Cancer Center - Arthur G.

Breast screening linked to 60 per cent lower risk of breast cancer death in first 10 years
Women who take part in breast screening have a significantly greater benefit from treatments than those who are not screened, according to a study of more than 50,000 women.

More clues revealed in link between normal breast changes and invasive breast cancer
A research team, led by investigators from Georgetown Lombardi Comprehensive Cancer Center, details how a natural and dramatic process -- changes in mammary glands to accommodate breastfeeding -- uses a molecular process believed to contribute to survival of pre-malignant breast cells.

Breast tissue tumor suppressor PTEN: A potential Achilles heel for breast cancer cells
A highly collaborative team of researchers at the Medical University of South Carolina and Ohio State University report in Nature Communications that they have identified a novel pathway for connective tissue PTEN in breast cancer cell response to radiotherapy.

Computers equal radiologists in assessing breast density and associated breast cancer risk
Automated breast-density evaluation was just as accurate in predicting women's risk of breast cancer, found and not found by mammography, as subjective evaluation done by radiologists, in a study led by researchers at UC San Francisco and Mayo Clinic.

Blood test can effectively rule out breast cancer, regardless of breast density
A new study published in PLOS ONE demonstrates that Videssa® Breast, a multi-protein biomarker blood test for breast cancer, is unaffected by breast density and can reliably rule out breast cancer in women with both dense and non-dense breast tissue.

Study shows influence of surgeons on likelihood of removal of healthy breast after breast cancer dia
Attending surgeons can have a strong influence on whether a patient undergoes contralateral prophylactic mastectomy after a diagnosis of breast cancer, according to a study published by JAMA Surgery.

Young breast cancer patients undergoing breast conserving surgery see improved prognosis
A new analysis indicates that breast cancer prognoses have improved over time in young women treated with breast conserving surgery.

Read More: Breast Cancer News and Breast Cancer Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to