Pre-diagnostic alcohol consumption and breast cancer recurrence and mortality: results from a prospective cohort with a wide range of variation in alcohol intake.

The association between pre-diagnostic alcohol consumption and breast cancer recurrence and breast cancer specific mortality was investigated in 1,052 women diagnosed with early breast cancer in a prospective cohort of 29,875 women. Known clinical, lifestyle and socioeconomic risk factors were evaluated and adjusted for in multivariate analysis. We found a modest but significant association between pre-diagnostic alcohol consumption and breast cancer recurrence with a median follow-up of six years after date of diagnosis, both when using baseline measures of alcohol intake (HR, 1.65; 95% CI, 1.02-2.67; >2 units/day vs. ≤1 unit/day) and cumulated alcohol intake (HR, 2.02; 95% CI, 1.06-3.85; >40 drinking years vs. 0<drinking years≤10). Results for breast cancer specific mortality were also suggestive of a higher risk but were not statistically significant. In addition to being a risk factor for breast cancer, a high pre-diagnostic alcohol intake also seems to have an effect on the course of the disease. We could not relate the finding to a specific tumor presentation.