Tamoxifen and endometrial cancer: most cancers are early stage and highly curable

A large randomised trial comparing tamoxifen with placebo for breast cancer treatment has demonstrated an average annual hazard rate for endometrial cancer in the placebo group of 0.2/1000 compared to 1.6/1000 for the tamoxifen-treated group, with tamoxifen causing a 7.5-fold increase in the relative risk of endometrial cancer. If the effect of tamoxifen on the endometrium is that of a weak oestrogen agonist, one could expect associated endometrial cancers to have clinical characteristics comparable to those associated with unopposed oestrogen i.e. low stage, well differentiated tumours that are highly curable. (C) 1998 Elsevier Science Ltd. All rights reserved.