Tamoxifen reduces the risk of contralateral breast cancer in premenopausal women: Results from a controlled randomised trial

In this randomised trial, adjuvant treatment using tamoxifen for 2 years reduced the incidence of contralateral breast cancer by 50% in all premenopausal women, and by 90% in women <40 years of age. The effect of tamoxifen was not significantly dependent on time.