Alcohol consumption linked to risk of lobular breast cancer in observational study

August 25, 2010

Self-reported alcohol consumption was found linked to the risk of developing invasive lobular breast cancer, but not invasive ductal breast cancer, in an analysis from the Women's Health Initiative Observation Study. 

Over 87,000 women were recruited into the Women's Health Initiative cohort from 1993 through 1998 and given a survey that included questions about alcohol consumption at the time of the survey. Invasive breast cancer was diagnosed in 2944 of the women during follow-up through 2005. In a statistical analysis, alcohol consumption was positively related to risk of invasive breast cancer overall, invasive lobular carcinoma, and hormone receptor–positive tumors.

Alcohol consumption was more strongly related to risk of certain types of invasive breast cancer compared with others. Compared with never drinkers, women who consumed seven or more alcoholic beverages per week had almost twice the risk of hormone receptor–positive invasive lobular carcinoma but not a statistically significant increased risk of hormone receptor–positive invasive ductal carcinoma.

The absolute rates of developing lobular breast cancer were still very low for all women.  The absolute rates of hormone receptor–positive lobular cancer among never drinkers and current drinkers were, 5.2 and 8.5 per 10 000 person-years, respectively, whereas for hormone receptor–positive ductal cancer they were 15.2 and 17.9 per 10 000 person-years, respectively.

A major limitation of the study is the one-time, self-report of alcohol use.  A previous history of alcohol consumption that differed from the self-report at the time of the survey, any changes in alcohol consumption over time, or the inaccuracy of the self-reports could all weaken the reliability of the study results.