Post-diagnostic coffee and tea consumption and breast cancer survival.

Abstract

We examined the role of post-diagnostic coffee and tea consumption in relation to breast cancer-specific and all-cause mortality among women with breast cancer in prospective cohort studies. We identified 8900 women with stage I-III breast cancer from 1980 through 2010 in the Nurses' Health Study (NHS) and from 1991 through 2011 in the NHSII. Post-diagnostic coffee and tea consumption was assessed by a validated food frequency questionnaire every 4 years after diagnosis. During up to 30 years of follow-up, we documented 1054 breast cancer-specific deaths and 2501 total deaths. Higher post-diagnostic coffee consumption was associated witha lower breast cancer-specific mortality: compared with non-drinkers, >3 cups/day ofcoffee was associated with a 25% lower risk (hazard ratio (HR) = 0.75, 95% confidence interval(CI) = 0.59-0.96; Ptrend = 0.002). We also observeda lower all-cause mortality with coffee consumption: compared withnon-drinkers,>2 to 3 cups/day was associated with a 24% lower risk (HR = 0.76, 95% CI = 0.66-0.87) and >3 cups/day was associated with a 26% lower risk (HR = 0.74, 95% CI = 0.63-0.87, Ptrend < 0.0001). Post-diagnostic tea consumption was associated witha lower all-cause mortality: compared with non-drinkers, >3 cups/day was associated with a 26% lower risk (HR = 0.74, 95% CI = 0.58-0.95; Ptrend = 0.04). Among breast cancer survivors, higher post-diagnostic coffee consumption was associated with better breast cancer and overall survival. Higher post-diagnostic tea consumption may be related to better overall survival.