Question: If I have my breasts removed, will that prevent or reduce my risk of getting breast cancer?
Answer: Well, from studies that have been done here at the Mayo Clinic and also information from Rotterdam in the Netherlands, I think that we know that prophylactic mastectomy does significantly reduce the risk of breast cancer. It does not take it to zero. There are a few women who will still develop a breast cancer in residual breast tissue on the chest wall. How common is that? In a study that we did here comparing women at hereditary risk who had prophylactic mastectomy, with their sisters, who obviously share the same hereditary risk, who did not have prophylactic mastectomy -- over a period of approximately 14 years, the sisters had developed 38 breast cancers; the women who had had the surgery had developed three breast cancers. So that's where the 90 percent risk reduction figure has come from. So, yes, I think that the procedure does significantly reduce risk, but it does not abolish the risk.