The absolute benefit of cancer prevention drugs like tamoxifen is modest for most individuals due to low baseline cancer risk.

“and did that reduction in Risk translate to a survival benefit or just an incidence it did not for a couple reasons one is obviously the risk is really low second um we have good treatments for those women who do develop breast cancer and third if you're using Tom oxin as a preventative arguably you're preventing the most treatable types of breast cancer from arising so you're pulling out the better actors if you will and what's left are tumors that remain somewhat resistant to the anti-estrogens and therefore more worrisome”