Bilateral breast cancers in an Asian population, and a comparison between synchronous and metachronous tumours.

Background: Women with unilateral breast cancer have an increased risk of developing bilateral breast cancer (BBC). Patients with metachronous BBC (mBBC) usually have an earlier age of onset, and their prognoses have been shown to be either similar or poorer than those with synchronous BBC (sBBC). Given the differing presentation and characteristics of breast cancers in the Asian population and the West, this study aims to characterize Asian patients with BBC.