Phytoestrogens after breast cancer

The current extension of the indications for adjuvant chemotherapy, which p redisposes to early menopause, and the media coverage of the benefits of ho rmone replacement therapy (HRT) have led patients with a history of breast cancer to seek treatments for estrogen deprivation. In breast cancer surviv ors, most physicians avoid HRT because of concern regarding the potential p romotion of growth of occult malignant cells by estrogens, due to the estro gen dependence of breast cancer. Soy phytoestrogens are being promoted as t he 'natural alternative' to HRT and have been available without restriction s for several years as nutritional supplements. In this paper, data on the complex mammary effects of phytoestrogens in epidemiological studies, in in vitro studies, as well as in in vivo studies on animal carcinogenesis are reviewed. The potential benefits and risks of phytoestrogens are analyzed, and the prescription of phytoestrogens to postmenopausal women after breast cancer and the coprescription with the anti-estrogen tamoxifen are discuss ed. The absence of controlled trials and technical checking of extraction a nd titration in these preparations on 'free sale' raise a new problem in te rms of public health and justify close reasoning and a cautious attitude of physicians, as well as straight information given to women, especially aft er breast cancer.