Bilateral synchronous breast cancer in an Asian population: mammographic and sonographic characteristics, detection methods, and staging.

OBJECTIVE: This study was performed to compare the clinical and radiologic findings and pathologic staging between index cancer and contralateral synchronous breast cancers and to determine the roles of mammography and sonography in their detection.
CONCLUSION: Additional contralateral breast cancers in bilateral synchronous breast cancers are apt to be small and less palpable and to have less suspicious imaging findings and less advanced cancer staging than the index cancer. Bilateral whole-breast sonography with mammography is useful in the early detection of contralateral synchronous breast cancer.