The impact of systemic therapy following ductal carcinoma in situ.

Following local therapy for ductal carcinoma in situ (DCIS), tamoxifen reduces the risk of ipsilateral and contralateral breast cancer by 30%-50%. Studies of tamoxifen in women with resected DCIS have not shown any effect on overall or cancer-specific survival. The adverse event profile of tamoxifen is well characterized, and individual risks and benefits should be assessed to guide decision making. We review the results of the phase III trials of tamoxifen in DCIS as well as the emerging risk reduction therapies.