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THURSDAY, July 3, 2003 (HealthDayNews) -- While removing breasts and ovaries of women at high risk for breast and ovarian cancers greatly reduces their chances of disease, it's actually unclear exactly how much the radical surgery helps.
That opinion comes in a commentary in the July 2 issue of the Journal of the National Cancer Institute.
The Dutch authors say studies examining the value of prophylactic surgery to prevent breast or ovarian cancer in these women may have overestimated or underestimated the benefits because of potentially unrecognized biases in study design.
Recognizing and understanding these biases may help scientists improve the design of future studies and better evaluate the results of previous studies, the authors say.
Women with certain mutations in the breast and ovarian cancer susceptibility genes BRCA1 and BRCA2 have an increased risk of developing breast and ovarian cancer.
Previous studies found prophylactic bilateral breast removal is associated with an 85 percent to 100 percent reduction in breast cancer risk. Other studies concluded that surgery to remove the ovaries is associated with a similar risk reduction for ovarian and breast cancer.
But these studies contain a number of potential biases, according to the commentary. These include familial-event bias, survival bias, detection bias, testing bias and confounding by other risk factors for breast and ovarian cancer.
These biases need to given serious consideration and warrant critical discussion about their potential impact on study results.
"Only in this way can BRCA1/2 mutation carriers, clinical geneticists and treating physicians obtain more accurate information about the true extent of cancer risk reduction from prophylactic surgery. This valid estimate of risk reduction may become even more crucial in the future when data become available regarding the efficacy of new surveillance methods, such as magnetic resonance imaging, and new chemoprevention agents, such as raloxifene," the authors write in a news release.
More information
Here's where you can learn more about breast cancer and ovarian cancer.
