Alcohol consumption and cancer risk.

This review focuses on selected aspects of the relation between alcohol consumption and cancer risk. Heavy alcohol consumption (i.e., ≥4 drinks/day) is significantly associated with an increased risk of about 5-fold for oral and pharyngeal cancer and esophageal squamous cell carcinoma, 2.5-fold for laryngeal cancer, 50% for colorectal and breast cancers, and 30% for pancreatic cancer. These estimates are based on a large number of epidemiological studies and are generally consistent across strata of several covariates. The evidence suggests that at low doses of alcohol consumption (i.e., ≤1 drink/day) the risk is also increased by about 20% for oral and pharyngeal cancer and 30% for esophageal squamous cell carcinoma. Thus, for these sites there is little evidence of a threshold effect. While consumption of fewer than 3 alcoholic drinks/wk is not associated with an increased risk of breast cancer, an intake of 3 to 6 drinks/wk might already yield a (small) increase in risk. On the other hand, intakes up to 1 drink/day are not associated to the risk of laryngeal, colorectal, and pancreatic cancer. The positive association between alcohol consumption and the risk of head and neck cancers is independent from tobacco exposure.