A large group of distinguished scientists published a very detailed and rather complex paper describing the association between alcohol consumption and cancer in the BMJ. It is based on data from the EPIC study in Europe, with a mean follow up of 8.8 years for more than 300,000 subjects. The authors describe an increase in risk of many cancers from alcohol intake, but do not give data permitting the detection of a threshold of intake for an adverse effect on cancer risk. The investigators conclude that "In western Europe, an important proportion of cases of cancer can be attributable to alcohol consumption, especially consumption higher than the recommended upper limits."
Members of the Forum were concerned that the authors did not separate moderate consumption from heavy consumption for their main analyses, ignored the demonstrated benefits of moderate drinking on total mortality, and did not point out other environmental influences (such as smoking, diet, obesity, etc.) that often have much larger effects on the risk of many cancers than does alcohol consumption. The authors make broad statements such as 'alcohol has negative effects on total mortality', which is not supported by the data presented in their paper, and is contradicted by most large-scale population-based studies. Overall, while this paper supports the well-known association between heavy drinking and an increased risk of upper aero-digestive and certain other cancers, it adds little information useful for the prevention of most types of cancer.
The full critique by forum members can be read via: http://www.bu.edu/alcohol-forum/critique-039-the-role-that-alcohol-drinking-may-play-in-the-risk-of-cancer-17-april-2011/