Alcohol consumption and prognosis and survival in breast cancer survivors: The Pathways Study.

Background: The impact of alcohol consumption on breast cancer (BC) prognosis remains unclear.

Methods: The authors examined short-term alcohol intake in relation to recurrence and mortality in 3659 women who were diagnosed with stage I-IV BC from 2003 to 2013 in the Pathways Study. Alcohol drinking in the past 6 months was assessed at cohort entry (mean, 2 months postdiagnosis) and 6 months later using a food-frequency questionnaire. Study end points were recurrence and death from BC, cardiovascular disease, and all causes. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multivariable Cox proportional hazards models.

Results: Over an average follow-up of 11.2 years, 524 recurrences and 834 deaths (369 BC-specific and 314 cardiovascular disease-specific) occurred. Compared with nondrinkers (36.9%), drinkers were more likely younger, more educated, and current or past smokers. Overall, alcohol consumption was not associated with recurrence or mortality. However, women with higher body mass index (BMI ≥ 30 kg/m2 ) had lower risk of overall mortality with increasing alcohol consumption for occasional drinking (HR, 0.71; 95% CI, 0.54-0.94) and regular drinking (HR, 0.77; 95% CI, 0.56-1.08) around the time of diagnosis, along with 6 months later, in a dose-response manner (p < .05). Women with lower BMI (<30 kg/m2 ) were not at higher risk of mortality but were at possibly higher, yet nonsignificant, risk of recurrence for occasional drinking (HR, 1.29; 95% CI, 0.97-1.71) and regular drinking (HR, 1.19; 95% CI, 0.88-1.62).

Conclusions: Alcohol drinking around the time of and up to 6 months after BC diagnosis was associated with lower risk of all-cause mortality in obese women. A possible higher risk of recurrence was observed in nonobese women.