Schűtze M, Boeing H, Pischon T, et al, Alcohol attributable burden of incidence of cancer in eight European countries based on results from prospective cohort study. BMJ 2011; 342:d1584 doi: 10.1136/bmj.d1584 (Published 7 April 2011)
Forum Comments
Overview: This is a very well-done analysis of data collected from the large EPIC study. The investigators had good follow-up data over a mean of 8.8 years on more than 300,000 subjects. There were large numbers of subjects developing the most common types of cancer, but limited numbers of cases of upper aerodigestive cancer and liver cancer. The authors classified a number of cancers as “alcohol-attributable;” many of these were “alcohol-related,” with the latter meaning that other factors (smoking, diet, obesity, etc.) may be more important “causes” of such diseases.
While this is a valuable dataset, the intentions of the authors in the preparation of this paper seem to focus mainly on indicting alcohol as a major cause of cancer. Many important observations that would be very helpful to clinicians (such as the role of moderate drinking, rather than intake greater than recommended, as a cause of cancer) are not presented clearly.
For example, the authors give very detailed tables of the proportion of cancer related to alcohol intake, but do not explicitly indicate the numbers of cases that relate just to heavy alcohol intake, even though they state that among men the percentage of cancers related to > 2 drinks/day accounted for 57% to 87% of the total alcohol-attributable fractions; consumption > 1/day accounted for 40% to 98% of the fractions for women. It would have been preferable if they presented data separately for associations with cancer incidence for moderate drinking and for heavier drinking.
It is also unfortunate that the authors do not present stratified data (separately for non –smokers and smokers) to clearly indicate the role that smoking plays in the development of certain cancers. For upper aero-digestive cancers, in particular, it would be important to demonstrate how smoking, independently and in an interaction with alcohol, relates to such cancers. As stated by one Forum reviewer: ¨Smoking is a well-known confounder of the alcohol-cancer association. However, the authors do not acknowledge that The Million Women Study1 found no association between cancers of the upper aerodigestive tract and intake of alcohol in non-smoking women.” Another reviewer comments that the authors state that “In the groups of never smokers the number of cases of cancer was limited in the EPIC study, which led to a limited power to assess the association between the consumption of alcohol and risk of cancer in this subgroup.” The authors do not comment that this is a serious problem; this raises concerns that the a priori purpose of the study was just to demonstrate an association between any alcohol intake and cancer. > > > > Read More
