] Preliminary research on the new drug suggests it could be
] much better at preventing breast cancer than tamoxifen,
] an earlier cancer "wonder drug". Tamoxifen reduces the
] risk of breast cancer by about a third. But crucially,
] anastrozole also has a much lower risk of side-effects,
] say researchers.

Interesting comparison of tamoxifen to anastrozole.

Major trial tackles breast cancer prevention: Anastrozole vs. Tamoxifen