Pre-diagnostic alcohol consumption and postmenopausal breast cancer survival: a prospective patient cohort study

Study results on the association of alcohol consumption with breast cancer survival are inconsistent, partly due to the use of different survival outcomes. We assessed the association of pre-diagnostic alcohol consumption with survival and recurrence in a prospective cohort study in Germany including 2,522 postmenopausal breast cancer patients aged 50-74 years. Patients were diagnosed between 2001 and 2005 and vital status, causes of death, and recurrences were verified through the end of 2009. Cox proportional hazards models were stratified by age at diagnosis and study center and adjusted for relevant prognostic factors. Alcohol consumption was non-linearly associated with increased breast cancer-specific mortality [e.g., ≥12 vs. <0.5 g/day: hazard ratio (HR) = 1.74, 95 % confidence interval (CI): 1.13, 2.67]. Results were independent of estrogen receptor status. A non-significantly decreased risk of mortality due to other causes was found (≥12 vs. <0.5 g/day: HR = 0.67, 95 % CI: 0.35, 1.29). Alcohol consumption was not associated with overall mortality (≥12 vs. <0.5 g/day: HR = 1.28, 95 % CI: 0.90, 1.81) and breast cancer recurrence (≥12 vs. <0.5 g/day: HR = 1.08, 95 % CI: 0.73, 1.58). In conclusion, our findings show that consumption of alcohol before diagnosis is non-linearly associated with increased breast cancer-specific mortality but may be associated with decreased risk of mortality due to other causes.