‘Don’t make the mistake of thinking that becoming a teetotaller means you’ll lower your risk of the disease (cancer)....Findings have to be looked at as one more piece of information among many risk factors. In the big scheme of things; [alcohol] is a small issue, compared with something such as family history. Follow a healthy lifestyle, with a good diet, exercise, and avoidance of smoking and heavy drinking’. Len Lichtenfeld, MD, American Cancer Society deputy chief medical officer.
A plethora of papers and reports on alcohol and cancer were published in February - have they revealed new trends or extended the evidence base?
Cancer is increasing in our society and is becoming the leading cause of mortality in the Western World, outstripping cardiovascular disease. It is also now the major cause of premature deaths, and the major cause of death, in the 45 to 65 year old age group.
It is estimated that cancer could be prevented in about 35% of cases by changing our behaviour to largely avoid known cancer risk factors. Smoking, diets rich in processed, cured or red meat, salt or salted fish and obesity are known risk factors for cancer - as is heavy drinking, especially when combined with smoking.
Alternatively, physical activity, and a diet rich in fibre, fruit and vegetables leading to ideal body weight (BMI) are known to protect against cancer, but it is unclear as to whether moderate drinking can be added to this list, unlike for heart disease, where it has been clearly shown to be an independent protective factor. It has not yet been able to establish a clear threshold at which cancer risk increases. The comprehensive report on alcohol as a cause of cancer published last year by the Australian Cancer institute (http://www.cancerinstitute.org.au/cancer_inst/publications/pdfs/pm-2008-03_alcohol-as-a-cause-ofcancer.pdf) concluded that moderate alcohol consumption corresponding to approximately two drinks of alcohol (10g) per day does not increase the risk of cancer in general. However, the average intake of approximately four drinks per day increases the risk of cancer by 22%. High alcohol consumption averaging approximately eight drinks per day increases the risk of cancer at any site by 90%. Evidence is clear, that alcohol is carcinogenic for some types of cancer, and that the risk is dose dependent.
New US report
The World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) Report – ‘Policy and Action for Cancer Prevention’ – sets out changes that can be made at all levels of society to reduce the number of cancer cases. The report includes estimates of the proportion of cancer cases that could be prevented through diet, physical activity and weight management.
A chapter is dedicated to alcohol and cancer and finds evidence for increased cancer risk as consumption level increases for some cancers. (Dose respondent)
‘The evidence that alcoholic drinks are a cause (as level of consumption increases, so does risk, with no clear threshold of safe consumption) for cancers of the mouth, pharynx, larynx, oesophagus and breast’. Colorectal cancer risk increases for men at levels of 30g and above a day. Alcohol is probably a cause of liver cancer, and of colorectal cancer in women. It is unlikely that alcoholic drinks have a substantial adverse effect on the risk of kidney cancer....The Panel judges that alcoholic drinks are or may be a cause of various cancers, irrespective of the type of alcoholic drink. The causal factor is evidently alcohol (ethanol) itself. The extent to which alcoholic drinks are a cause of various cancers depends on the amount of alcohol drunk’.
UK’s million women study
The report that attracted the most attention is sponsored by Cancer Research UK and was published in the Journal of the National Cancer Institute
Allen’s study is an observational one, based on data from the UK’s Million Women Study, which is a study about the association between Hormone Replacement Therapy, cancer and heart disease. Allen’s study included self-reported alcohol consumption. As an observational study, causal conclusions about a link between drinking and cancer cannot realistically be drawn, but the study finds that the incidence of all types of cancer studied in its non-drinking subjects was 5.7 per cent compared with 5.3 per cent for those subjects who had at least a drink a day, and up to 14 drinks a week - i.e. Teetotallers had a higher population incidence of cancer than those consuming up to 14 drinks a week. The study looked at 21 types of cancer incidence. Of these, it found statistically significant associations between drinking and four types of cancer. The association with breast cancer, with by far the largest number of cases in the study (almost 22,000), was non-significant. See the summary by R. Curtis Ellison on page 7.
French report
A third report from Nutrition & Prévention des cancers from France has a chapter dedicated to alcohol and received considerable coverage in the press.
It estimates that in 2007, the proportion of cancers attributable to alcohol in France was 10.8 % for men and 4.5 % for women in 2000 (IARC, 2007).
