Dioxins Exposure and the Risk of Breast Cancer: A Systematic Review and Meta-Analysis

Context: Dioxins and dioxin-like chemicals composed of 419 compounds are a large group of compounds, including polychlorinated di-benzo-p-dioxins (PCDDs), dibenzofurans (PCDFs), and biphenyls (PCBs). Dioxins are extremely persistent in the environment and disperse in a great distance from the emission source, and bioaccumulation in the food chain is one of their critical properties. The incidence of breast cancer among Iranian women is about 30 to 35 per 100,000 cases. The present study is a systematic review of published studies in English language to discover the relationship between exposure to dioxin compounds and breast cancer. Methods: We conducted a comprehensive literature review utilizing PubMed, Embase, Scopus, and ISI web of science databases. The MeSH-based keywords used included Organic Chemical (MeSH) OR Dioxins (MeSH) AND cancer (MeSH) OR Breast cancer (MeSH) AND Breast disease (MeSH). Results: The review of the literature indicated a significant positive association between dioxins exposure and the risk of breast cancer. Only in one study, breast cancer mortality rate was reported in terms of exposure to dioxins, and standardized mortality rates (SMRs) were determined. Conclusions: Although there were limitations in this study, statistical analyses in various epidemiological studies demonstrated that dioxins exposure is linked to an increased risk of breast cancer.