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.