The impact of xenoestrogens on effectiveness of treatment for hormone-dependent breast cancer - current state of knowledge and perspectives for research

Introduction. Breast cancer is the most common cancer occurring in women and causing the highest number of deaths among them. The role of xenoestrogens has been the subject of many studies in the pathogenesis of breast cancer. Less is known about the impact of xenoestrogens on the effectiveness of hormone therapy used to treat breast cancer, and thus possible drug-xenostrogen interactions. Objective. The aim of this review is to summarize the current state of knowledge and present perspectives for further research on the impact of xenoestrogens on the effectiveness of drugs used in the treatment of hormone-dependent breast cancer. Current state of knowledge. Phytoestrogens, in particular flavonoid genistein, are the best studied group of xenoestrogens in terms of interaction with drugs used in the treatment of breast cancer, due to their frequent use, including their use in alleviating the adverse effects of hormone therapy. Analyzing the current state of knowledge, it seems that phytoestrogens intake should be avoided during conventional anti-cancer treatment. Of the other xenoestrogens, bisphenol A (BPA) is one of the best-tested compounds for interactions with drugs used to treat breast cancer. It has been shown that bisphenol A could reduced therapeutic effect of active tamoxifen metabolite and cytostatics used in breast cancer treatment. Conclusion. Confirmation in clinical trials of the results obtained in vitro and in vivo tests, would enable the creation of specific recommendations for patients undergoing breast cancer treatment, especially hormone therapy. An area requiring further research is the analysis of the effects of xenoestrogens other than phytoestrogens, e.g. metalloestrogens, on the effects of drugs used in the treatment of breast cancer.