More Evidence Linking Long-Term Alcohol Consumption with Breast, Upper Aero-Digestive Tract, and Colorectal Cancers

Ethanol is carcinogenic to humans, but the biological mechanisms are not fully understood. This systematic review and meta-analysis examined the association of long-term alcohol intake with upper aero-digestive tract, colorectal, and (for women) breast cancers. To be included, studies had to measure alcohol intake for different periods of life (based on age) or report more than one assessment of consumption over time. The authors identified 16 articles for upper aero-digestive tract, 74 for colorectal, and 16 for breast cancer.

• There was a positive linear dose-response relationship between long-term alcohol intake and upper aero-digestive tract and colorectal cancer incidence.
• There was a positive non-linear dose-response relationship between long-term alcohol intake and breast cancer incidence.
• The pooled risk ratio (highest versus lowest category of long-term alcohol intake as categorized in each of the identified studies) was 2.83 for upper aero-digestive tract, 1.49 for colorectal, and 1.28 for breast cancer.
  • Specifically, the pooled risk ratio was 4.84 for cancer of the oral cavity and pharynx, 2.25 for larynx, and 6.71 for esophagus.

Comments:

This study provides further evidence of the association between alcohol intake over time and cancer. The included studies did not take into account the pattern of intake, which would allow for a more detailed measure of alcohol consumption. This would be important in differentiating a cumulative carcinogenic effect from a tumor-promoting effect (in which a high daily alcohol intake for a short period of time would be associated with a higher risk of cancer than a lower daily intake for a longer duration).

Nicolas Bertholet, MD, MSc

Reference:

Jayasekara H, MacInnis RJ, Room R, English DR. Long-term alcohol consumption and breast, upper aero-digestive tract and colorectal cancer risk: a systematic review and meta-analysis. Alcohol Alcohol. 2015 [Epub ahead of print]. pii: agv110.