BackgroundGastrointestinal cancer is an age-associated disease, and geriatric patients are mostly likely to suffer from postoperative complications. Some studies indicated that comprehensive geriatric assessment (CGA) could predict postoperative complications in gastrointestinal cancer patients. However, the evidence is mixed.ObjectiveThis study aimed to conduct a meta-analysis to identify the effectiveness of CGA for predicting postoperative complications in gastrointestinal cancer patients.MethodsThe Joanna Briggs Institute Library, Cochrane Library, PubMed, Embase, Web of Science, CINAHL Complete and four Chinese databases were searched for studies published up to March 2017. Two reviewers independently screened literature, extracted data and assessed the quality of included studies. RevMan5.3 was used for meta-analysis or only descriptive analysis.ResultsSix studies were included, with 1,037 participants in total. In all, 13 components of CGA were identified, among which comorbidity (Charlson Comorbidity Index [CCI] ≥3; odds ratio [OR]=1.31, 95% CI [1.06, 1.63], P=0.01), polypharmacy (≥5 drugs/day; OR=1.30, 95% CI [1.04, 1.61], P=0.02) and activities of daily living (ADL) dependency (OR=1.69, 95% CI [1.20, 2.38], P=0.003) were proven relevant to the prediction of postoperative complications. No conclusive relationship was established between instrumental activities of daily living (IADL) dependency (OR=1.18, 95% CI [0.73, 1.91], P=0.51), Mini-Mental State Examination (MMSE; OR=1.13, 95% CI [0.91, 1.41], P=0.27), potential malnutrition (OR=1.07, 95% CI [0.87, 1.31], P=0.54), malnutrition (OR=1.26, 95% CI [0.80, 1.99], P=0.32), Geriatric Depression Scale (GDS; OR=1.18, 95% CI [0.90, 1.55], P=0.24) and postoperative complications.ConclusionComorbidity (CCI ≥3), polypharmacy (≥5 drugs/day) and ADL dependency were predictive factors for postoperative complications in gastrointestinal cancer patients; the results of other geriatric instruments were not conclusive, pointing to insufficient studies and requirement of more original investigations.