The association between alcohol consumption and the risk of breast cancer has been reported fairly consistently in numerous studies.
Willett and colleagues reported a significant association in the first prospective study with detailed exposure information. Howe and colleagues demonstrated an association in a meta-analysis of six case–control studies designed to investigate nutrition and cancer. In a meta-analysis of 38 epidemiologic studies, the pooled risk estimates were 1.1 (95% CI, 1.1 to 1.2) for one drink per day, 1.2 (95% CI, 1.1 to 1.3) for two drinks per day, and 1.4 (95% CI, 1.2 to 1.6) for three or more drinks per day, relative to nondrinkers. A pooled analysis of six prospective studies reported similarly modest increases in risk, with a dose-dependent trend between alcohol consumption and breast cancer risk, after taking into account the major risk factors. In another pooled analysis of 53 epidemiologic studies, for each additional 10 g/day increase in alcohol intake, an increase in breast cancer risk of 7.1% (standard error, 1.3%) was reported in never smokers. Differences in risk due to alcohol beverage types have not been observed. The association is consistent among both premenopausal and postmenopausal women, although there is evidence emerging that the effect may be greater in (or confined to) ERpositive/PR-positive breast cancer.
The third version of the European Code Against Cancer incorporated the growing body of evidence into Point 5 of the Code, recommending that women limit their alcohol consumption to one drink per day in view of the risk of breast cancer. This level was one-half of the recommended daily
limit for men. On the basis of the growing body of evidence, the International Agency for Research on Cancer convened a Working Group to prepare a Monograph on Alcohol Drinking in February 2007. The Group concluded there was sufficient evidence that the risk of breast cancer was increased by alcohol consumption. Very recent studies, notably from the Million Women Study, have strengthened knowledge of the impact of moderate alcohol consumption levels on increasing the risk of breast cancer.
Overall, there is a large body of evidence consistent with alcohol consumption increasing the risk of breast cancer. There is consistent evidence from large, prospective studies that even moderate alcohol consumption increases the risk of breast cancer.
Título: Alcohol consumption and breast cancer risk
Autores: Peter Boyle, Paolo Boffetta
Fonte: Breast Cancer Research 2009, 11(Suppl 3):S3 (18 December 2009)