Patient demographic and clinicopathological characteristics.

sBBC: synchronous bilateral breast cancer; UBC: unilateral breast cancer.*Carcinomas with lobular carcinoma component involvement in either breast were classified as Lobular, while those with the involvement of other carcinoma components, with the exception of ductal or lobular carcinoma, in either breast were classified as Other.**ER or c-erbB-2 expression in either breast was considered positive.***Sclerosing adenosis was a major component, including carcinomas arising from sclerosing adenosis and carcinomas involved with sclerosing adenosis.