The incidence for breast and other female-hormone-related neoplasms levels off after menopause. The relative risk (RR) of breast cancer is moderately elevated in current and recent users of hormone replacement therapy (HRT) and increases by about 2.3% per year with longer duration of use, but the effect drops after cessation. Unopposed oestrogen use is strongly related to endometrial cancer risk but cyclic combined oestrogen-progestin treatment appears to reduce this side-effect. However, combined HRT may be associated with higher risk of breast cancer as compared to unopposed oestrogens. Ovarian cancer may also be unfavourably influenced by the use of HRT. HRT has been related to decreased risk of colorectal cancer, the overall RR being about 0.8. Tamoxifen and other selective oestrogen receptor modulators (SERMs) may have a favourable effect on the risk of breast cancer but their risk-benefit profile requires further quantification. The potential effect of 'natural' SERMs (phytoestrogens) on cancer risk remains undefined.
Copyright 2002 Elsevier Science Ltd.