A new prospective study has reported that consuming at least three to four alcoholic drinks per week after a breast cancer diagnosis increases the risk of breast cancer recurrence, especially for postmenopausal and overweight or obese women. The study was designed to investigate the association between alcohol consumption after a diagnosis of early-stage breast cancer and breast cancer recurrence and mortality. It included 1,897 women primarily from the Kaiser Permanente Northern California Cancer Registry who had been diagnosed with early-stage breast cancer between 1997 and 2000. Study participants were recruited into the study two years after diagnosis, on average. Alcohol consumption (wine, beer, and liquor) was determined upon enrollment using a questionnaire. A total of 293 breast cancer recurrences and 273 deaths from all causes occurred during the study follow-up period, which lasted 7.4 years, on average.

Approximately half (51%) of the women were classified as alcohol drinkers (consumption greater than 0.5 g per day of alcohol); the majority drank wine (89%). Compared to not drinking alcohol, drinking at least 6 g/day of alcohol was found to be associated with a 35% increased risk of breast cancer recurrence and a 51% increase in death due to breast cancer. The increased risk of recurrence was concentrated among postmenopausal (51% higher risk) and overweight and obese women (60%). Alcohol intake was not associated with all-cause death. In fact, there appeared to be a decreased risk of death from causes other than breast cancer, indicating a cardioprotective effect for moderate alcohol consumption. The results suggest that while thin women may not be harmed by moderately low alcohol consumption, overweight and postmenopausal breast cancer survivors should limit their intake.