Alcohol and cancer risk, with focus on moderate drinkers

Abstract

AAlcohol substantially increases the risk of head and neck and oesophageal cancers. The risks are essentially due to total ethanol intake. Alcohol drinking has also been associated with primary liver cancer, with cancers of the large bowel in both sexes, of the female breast, and –at high doses onlyof the pancreas [1]. To evaluate the strength of the evidence provided by the epidemiological literature on the association between alcohol consumption and the risk of 18 known or potentially alcohol-related neoplasms, we performed a search of the epidemiological literature from 1966 to 2012 using major bibliographic data-bases. We fitted meta-regression models considering linear and non-linear effects of alcohol intake. We also investigated the effects of selected characteristics of the studies (e.g., allowance for tobacco) and of individuals included in the studies (e.g., gender, age, etc.), as possible sources of heterogeneity of the estimates. A total of approximately 600 studies including 200,000 cases were considered. Strong trends in risk were observed for cancers of the oral cavity, oesophagus and larynx, the strongest one being for oral cancer, with a relative risk (RR) around 5 for 50 g/day of alcohol. Direct relations were also observed for cancers of the colon and rectum, liver, breast, and (for high doses only) pancreas [2]. We also specifically considered the association between light alcohol consumption and cancer risk for those sites for which there is sufficient or limited evidence for carcinogenicity of alcohol [1, 3]. Thus, we considered cancers of the upper digestive and respiratory tract (oral and pharyngeal cancer, esophageal squamous cell carcinoma but not adenocarcinoma of the esophagus, that is not associated to alcohol drinking [4] and laryngeal cancer), liver, colorectum, pancreas and breast. Quantification of the association between low doses of alcohol consumption and cancers known to be alcohol-related is particularly important, as it is still unclear (1) Department of Clinical Sciences and Community