Alcohol Consumption and Breast Cancer Recurrence
Abstract & Commentary
By William B. Ershler, MD
Synopsis: Consumption of alcohol among women who had received primary treatment for breast cancer was not associated with increased risk of breast cancer recurrence. In fact, for non-obese patients, alcohol intake was associated with other favorable prognostic factors and improved overall survival.
Source: Flatt SW, et al. Low to moderate alcohol is not associated with increased mortality after breast cancer. Cancer Epidemiol Biomarkers Prev. 2010;19:681-688.
There have been conflicting reports about alcohol intake and breast cancer risk. It is apparent that there is a higher risk of developing breast cancer among consumers.1-3 However, recent reports have suggested that recurrence rates are lower among those who consume low-to-moderate amounts when compared to those who abstain.4,5 Yet, this finding of a protection conferred by moderate alcohol consumption is somewhat controversial, as others, particularly from Europe, have found no effect.6,7 It is possible that the observed differences might relate to the lower level of alcohol consumed in the United States and/or differences in confounding variables, such as the presence or absence of obesity. Thus, to address this issue, Flatt and co-investigators from the Women's Healthy Eating and Living (WHEL) study examined the roles of alcohol intake and obesity as predictors of additional breast cancer events and all-cause mortality in a large cohort of breast cancer survivors. This was a randomized dietary intervention trial8,9 that did not include modifying alcohol intake as a variable, although alcohol consumption was determined prior to and during the course of the study.
Thus, alcohol intake (beer, wine, and spirits) was examined in their cohort of 3,088 women who had previously been diagnosed and treated for breast cancer. Factors associated with baseline alcohol intake were included in Cox proportional hazards models for recurrence and mortality. They found that alcohol intake was significantly associated with higher-education and physical-activity levels. Neither light alcohol intake nor obesity was significantly associated with breast cancer recurrence, but moderate alcohol intake > 300 g/mo (i.e., approximately one drink per day) was protective against all-cause mortality (hazard ratio, 0.69; 95% confidence intervals, 0.49-0.97) in a proportional hazards model adjusted for obesity. Obese women were 61% more likely to be non-drinkers than drinkers and 76% more likely to be light drinkers than moderate/heavy drinkers. In non-obese women, alcohol intake > 10 g/mo was associated with lower risk of all-cause mortality (hazard ratio, 0.68; 95% confidence intervals, 0.51-0.91).
Thus, it appears that light alcohol intake, regardless of body weight, did not increase the risk of breast cancer recurrence or all-cause mortality in this cohort of middle-aged women previously diagnosed with breast cancer. In fact, a moderate level of alcohol consumption (approximately one alcoholic drink per day) was associated with reduced all-cause mortality, particularly among women who were not obese).
It remains unclear whether alcohol itself influences breast cancer directly. Certain bioactive constituents in beer and wine, such as flavonoids and polyphenols, have been postulated to reduce cancer mortality,10 but clearly other mechanisms might be at play. Nonetheless, it is equally likely that the effect relates more to correlates of alcohol intake. In the current study, non-obese women with higher education and physical activity were more likely to consume moderate amounts of alcohol, and it is fairly well established that those of higher socioeconomic status are more likely to have improved health outcomes.
Thus, although there is sound evidence that alcohol consumption is a risk factor for incident breast cancer, moderate use among survivors of primary therapy is not associated with a higher recurrence rate and may be associated with overall improved survival.
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