Abstract and Introduction
Alcohol consumption by adult women is consistently associated with risk of breast cancer. Several questions regarding alcohol and breast cancer need to be addressed. Menarche to first pregnancy represents a window of time when breast tissue is particularly susceptible to carcinogens. Youth alcohol consumption is common in the USA, largely in the form of binge drinking and heavy drinking. Whether alcohol intake acts early in the process of breast tumorigenesis is unclear. This review aims to focus on the influences of timing and patterns of alcohol consumption and the effect of alcohol on intermediate risk markers. We also review possible mechanisms underlying the alcohol-breast cancer association.
Alcohol is considered by the International Agency for Research on Cancer to be causally related to breast cancer risk, with a 7–10% increase in risk for each 10 g (~1 drink) alcohol consumed daily by adult women.[2–4] This association is observed in both premenopausal and postmenopausal women. Compared with other organs, breast appears to be more susceptible to carcinogenic effects of alcohol. The risk of breast cancer is significantly increased by 4–15% for light alcohol consumption (≤1 drink/day or ≤12.5 g/day)[2,5,6] which does not significantly increase cancer risk in other organs of women. This raises a clinical and public health concern because nearly half of women of child-bearing age drink alcohol and 15% of drinkers at this age have four or more drinks at a time. Approximately 4–10% of breast cancers in the USA are attributable to alcohol consumption,[2,5,6] accounting for 9000–23,000 new invasive breast cancer cases each year. Therefore, better understanding of how alcohol consumption increases breast cancer risk is crucial for developing breast cancer prevention strategies. As previous meta-analyses and systemic reviews comprehensively summarized the association between adult alcohol consumption and breast cancer risk,[3,5,9,10] here we reviewed the recent epidemiologic evidence, with special emphasis on timing and patterns of alcohol consumption and the effect of alcohol on intermediate markers. In addition, we discussed up-to-date mechanisms that have been proposed to explain the association and provide guidance for clinicians on preventive messages.
Women's Health. 2015;11(1):65-77. © 2015 Future Medicine Ltd.