A woman with oestrogen-dependent breast cancer asks if it is safe to take phytoestrogen supplements.
A patient of mine who has breast cancer, and is postmenopausal, has asked me if it is safe for her to take phytoestrogens in tablet form, or as an increased component of her diet. She has read of the benefits of phytoestrogens in relieving menopausal symptoms, but is concerned that her oestrogen-dependent cancer may be stimulated by these supplements. What should I tell her? Would these supplements interfere with the tamoxifen she is taking? Would it be different if her cancer were oestrogen-receptor negative?