Moderate Alcohol Consumption and Cancer

Alcohol consumption may increase the risk for at least six types of cancer, although the evidence is not uniformly strong. Alcohol is not a carcinogen in standard tests but is likely a cocarcinogen, at least in the digestive tract. The strongest association is with cancer of the oral cavity and pharynx (seven-fold increase for heavy consumption). For moderate consumption (2-3 drinks/day for men and 1-2 drinks/day for women), the risks never increase above twofold and are mostly less than 25% above baseline. The evidence from the epidemiological literature suggests that 25g/d of alcohol is associated with a relative risk of 1.9 for cancers of the oral cavity and pharynx, 1.4 for cancers of the esophagus and larynx, about 10% for colorectal cancer (mechanisms unclear), and 20% for liver cancer (mechanisms well described). The association between alcohol and breast cancer is not strong and not necessarily causative, at least for moderate consumption. In the United Kingdom, cancer deaths attributable to alcohol consumption above the recommended limits (caused mostly by colorectal cancer) are maximal for men aged 65 to 74 years and for women at ages 75 to 84 years. It is postulated that if everyone in the United Kingdom drank "sensibly," there would be a marked increase in cancer deaths.