Postdiagnostic fruit and vegetable consumption and breast cancer survival: Prospective analyses in the nurses' health studies

Abstract

Fruits and vegetables contain many bioactive components that may contribute to improved survival after diagnosis of breast cancer, however, evidence to date is insufficient. We prospectively assessed the associations of postdiagnostic fruit and vegetable consumption with breast cancer-specific and all-cause mortality among 8,927 women with stage I-III breast cancer identified during follow-up of the Nurses' Health Study (NHS; 1980-2010) and NHSII (1991-2011), using a validated food frequency questionnaire completed every 4 years after diagnosis. We prospectively documented 2,521 deaths, including 1,070 from breast cancer through follow-up until 2014 in the NHS and 2015 in the NHSII. Total fruit and vegetable and total vegetable consumption was related to lower all-cause [HRQ5vsQ1, 0.82; 95% confidence interval (CI), 0.71-0.94; Ptrend = 0.004, and HRQ5vsQ1, 0.84; 95% CI, 0.72-0.97; Ptrend = 0.001, respectively], but not breast cancer-specific mortality. Total fruit consumption was not related to breast cancer-specific or allcause mortality. Greater intake of green leafy and cruciferous vegetables was associated with lower all-cause mortality. Each 2 servings/week of blueberries was associated with a 25% (HR, 0.75; 95% CI, 0.60-0.94) lower breast cancer-specific and a 17% (HR, 0.83; 95% CI, 0.72-0.96) lower all-cause mortality. In contrast, higher fruit juice consumption was associated with higher breast cancer-specific (HRQ5vsQ1, 1.33; 95% CI, 1.09-1.63; Ptrend = 0.002) and all-cause mortality (HRQ5vsQ1, 1.19; 95% CI, 1.04-1.36; Ptrend= 0.003). Apple juice largely accounted for these higher risks and orange juice was not associated with risk. Higher postdiagnostic fruit and vegetable consumption among breast cancer survivors was not associated with breast cancer-specific mortality. However, our findings suggest that higher vegetable consumption, particularly green leafy and cruciferous vegetables, was associated with better overall survival among patients with breast cancer. Higher fruit juice consumption, but not orange juice, was associated with poorer breast cancer-specific and all-cause survival. Significance: A large-scale study shows that high fruit and vegetable consumption may be associated with better overall survival among breast cancer patients, while high fruit juice consumption may be associated with poorer prognosis.