In a study recently completed at the Abramson Cancer Center at the Hospital of the University of Pennsylvania, researchers statistically concluded that the surgical removal of both breasts drastically reduces the risk of breast cancer in some women.
Over the past six years, researchers from Penn have conducted a study to assess the effectiveness of a prophylactic double mastectomy -- surgical removal of both breasts -- in women with certain gene mutations that make them most susceptible to cancer.
Although the procedure is extreme, the study shows a 95 percent reduction in breast cancer recurrences.
While the study's conclusions may seem fairly obvious, scientists said that the procedure had never been closely studied for effectiveness before.
This study, dubbed the Prevention and Observation of Surgical Endpoints, involved about a dozen other cancer research centers from around the world and surveyed 483 women carrying BRCA-1 and BRCA-2 gene mutations.
Women carrying these gene mutations have a much greater risk of having breast cancer.
In the study, 105 women had double mastectomies, and two were later diagnosed with cancer. This 1.9 percent rate is significantly lower than the almost 50 percent diagnosed in women who have the gene mutation and did not have the surgery.
The number of women that carry these mutations varies with ethnicity and country.
In the United States, about "one or two in every 1,000 women" have these mutations, but in some groups, the mutation can be as common as "1 or 2 percent," said Timothy Rebbeck, co-program leader of cancer epidemiology and risk reduction at the University Cancer Center.
The surgery itself was performed in some cases before this study was conducted, but "we never really knew how much the risk is reduced," said Jill Stopfer, a genetic counselor who works with patients to decide whether they need the surgery.
"This is a pretty extreme thing, done only after high consideration," Rebbeck said.
Rebbeck explained that the double mastectomy is one of the "very few options available to reduce risk" for these gene mutation carriers.
The fact that the double mastectomy reduces the risk of breast cancer for mutation carriers produces mixed results based on family history and assessment of other options, Stopfer said.
But the information provided by the study is an "important piece of information used in deciding whether or not to have the surgery," she added.
In the U.S., almost 200,000 women were diagnosed with breast cancer in 2001, and about 3 to 10 percent of these cases were estimated as being caused by BRCA-1 and BRCA-2 mutations, according to a HUP press release.
