Alcohol and cancer.

Although ethanol has generally not been found to induce cancer in experimental animals, the consumption of alcoholic beverages has been linked to increased risks of several cancers in humans. Risks of oral, pharyngeal, laryngeal, esophageal, and liver cancer are elevated among drinkers, typically in proportion to the amount consumed. Evidence associating colorectal and breast cancer with alcohol drinking is suggestive but awaits confirmation. All types of alcoholic beverages seem to be implicated, pointing to an etiological role for ethanol or its metabolites. The mechanisms, however, by which alcohol induces cancer in humans are not clear. This review summarizes epidemiological studies of alcohol and cancer, focusing primarily on characteristics of the association that may provide clues to causal pathways.