Effect of diet on mortality and cancer recurrence among cancer survivors: a systematic review and meta-analysis of cohort studies

CONTEXT: Evidence of an association between dietary patterns and individual foods and the risk of overall mortality among cancer survivors has not been reviewed systematically. OBJECTIVE: The aim of this meta-analysis of cohort studies was to investigate the association between food intake and dietary patterns and overall mortality among cancer survivors. DATA SOURCES: The PubMed and Embase databases were searched. STUDY SELECTION: A total of 117 studies enrolling 209 597 cancer survivors were included. DATA EXTRACTION: The following data were extracted: study location, types of outcome, population characteristics, dietary assessment method, risk estimates, and adjustment factors. RESULTS: Higher intakes of vegetables and fish were inversely associated with overall mortality, and higher alcohol consumption was positively associated with overall mortality (RR, 1.08; 95%CI, 1.02-1.16). Adherence to the highest category of diet quality was inversely associated with overall mortality (RR, 0.78; 95%CI, 0.72-0.85; postdiagnosis RR, 0.79; 95%CI, 0.71-0.89), as was adherence to the highest category of a prudent/healthy dietary pattern (RR, 0.81; 95%CI, 0.67-0.98; postdiagnosis RR, 0.77; 95%CI, 0.60-0.99). The Western dietary pattern was associated with increased risk of overall mortality (RR, 1.46; 95%CI, 1.27-1.68; postdiagnosis RR, 1.51; 95%CI, 1.24-1.85). CONCLUSION: Adherence to a high-quality diet and a prudent/healthy dietary pattern is inversely associated with overall mortality among cancer survivors, whereas a Western dietary pattern is positively associated with overall mortality in this population.