Post-diagnosis Soy Food Intake and Breast Cancer Survival: A Meta-analysis of Cohort Studies

Background and
Objectives: Data on associations between soy food intake after cancer diagnosis with breastcancer survival are conflicting, so we conducted this meta-analysis for more accurate evaluation.
Methods:Comprehensive searches were conducted to find cohort studies of the relationship between soy food intake aftercancer diagnosis and breast cancer survival. Data were analyzed with comprehensive meta-analysis software.
Results: Five cohort studies (11,206 patients) were included. Pooling all comparisons, soy food intake afterdiagnosis was associated with reduced mortality (HR 0.85, 95%CI 0.77 0.93) and recurrence (HR 0.79, 95%CI0.72 0.87). Pooling the comparisons of highest vs. lowest dose, soy food intake after diagnosis was again associatedwith reduced mortality (HR 0.84, 95%CI 0.71 0.99) and recurrence (HR 0.74, 95%CI 0.64 0.85). Subgroup analysisof ER status showed that soy food intake was associated with reduced mortality in both ER negative (highestvs. lowest: HR 0.75, 95%CI 0.64 0.88) and ER positive patients (highest vs. lowest: HR 0.72, 95%CI 0.61 0.84),and both premenopausal (highest vs. lowest: HR 0.78, 95%CI 0.69 0.88) and postmenopausal patients (highestvs. lowest: HR 0.81, 95%CI 0.73 0.91). In additioin, soy food intake was associated with reduced recurrence inER negative (highest vs. lowest: HR 0.64, 95%CI 0.44 0.94) and ER+/PR+ (highest vs. lowest: HR 0.65, 95%CI0.49 0.86), and postmenopausal patients (highest vs. lowest: HR 0.67, 95%CI 0.56 0.80).
Conclusion: Our metaanalysisshowed that soy food intake might be associated with better survival, especially for ER negative, ER+/PR+, and postmenopausal patients.