Association of Alcohol Intake with the Risk of Different Types of Breast Cancer

To determine associations between alcohol consumption and the risk of breast cancer, this study examined data from a clinical trial of enhanced screening for prostate, lung, colorectal, and ovarian cancer. During a follow-up period averaging about 9 years, a total of 1905 women were diagnosed with invasive breast cancer.

• There was an increase in breast cancer risk associated with alcohol intake for estrogen and progestin-positive (ER+/PR+) tumors, but not for other histologic types of breast cancer.
• The increased risk was predominantly seen among PR+ cancers (< ½ drink in a week [relative risk (RR), 1.15] and ½ – < 1 drink in a week [RR, 1.25]). There was no evidence of an increase in risk from alcohol consumption for women with ER+/PR- tumors.

Comments:

The analyses for this study were well done, although details about alcohol consumption were limited, folate levels were not assessed, the associations might be explained by factors other than alcohol (especially since such low doses might not plausibly increase risk), and the results might not generalize to a lower socioeconomic status population. But the main advance this study provides is the suggestion that alcohol’s effects on the development of breast cancer may differ by type of breast cancer. These findings might lead to a greater understanding of how to better prevent such cancers.

R. Curtis Ellison, MD

Reference:

Falk RT, Maas P, Schairer C, et al. Alcohol and risk of breast cancer in postmenopausal women: an analysis of etiological heterogeneity by multiple tumor characteristics. Am J Epidemiol. 2014;180(7):705–717.