Chemoprevention: beyond tamoxifen

Excerpt

Four trials have now reported on the use of tamoxifen for the prevention of breast cancer and one trial on the use of raloxifene. Overall, more than 28,000 women have participated in tamoxifen prevention trials and more than 140,000 women-years of follow up have accrued. Although early reports on the ability of tamoxifen to prevent breast cancer were apparently contradictory, with further follow up a consensus is now emerging indicating that 30–40% of breast cancers can be prevented by tamoxifen [1]. The benefit is restricted to oestrogen receptor positive tumours, where it is about 50%, but no reduction in receptor negative tumours has been found. Thrombo-embolic events are emerging as the most important side effects, and endometrial cancers are increased about twofold, although these are almost all low/intermediate grade, stage I cancers. …