[Characteristics of familial breast cancer]

We report the clinical characteristics of familial breast cancer families at our hospital in which the number of second-degree of breast cancer probands was more than 2. In our hospital, the incidence of onset at a young age was 21.9%, and bilateral breast cancer was 10.5%. These incident rates were significantly higher than sporadic breast cancer. The frequency of familial breast cancer in most Japanese hospitals was about 1.1%, but was 2.0% in our hospital. Familial breast cancer is a rare breast cancer, but the risk is high in breast cancer families. Therefore, it is necessary to follow up not only patients but the families.