Prognostic significance of the albumin-to-alkaline phosphatase ratio in gastrointestinal cancer patients: a systematic review and meta-analysis

BACKGROUND: The albumin-to-alkaline phosphatase ratio (AAPR), a simple and cost-effective prognostic parameter, has not been thoroughly investigated in relation to gastrointestinal (GI) cancers. METHODS: Relevant studies were retrieved from databases including Web of Science, Cochrane Library, Embase, and PubMed up to February 2025. Survival outcomes were presented as hazard ratios (HRs) with 95% confidence intervals (CIs). Heterogeneity was evaluated using the I2 statistic and Cochrane's Q test. When significant heterogeneity was detected ( I2 ≥ 50% or P ≤ 0.05), a random-effects model was employed; otherwise, a fixed-effects model was utilized. Statistical analyses were conducted using STATA 18.0 software. RESULTS: Eight studies involving 2267 patients with GI cancer were analysed. The pooled results of overall survival (OS) from both univariate and multivariate analyses indicated a significantly higher risk of death in the low-AAPR group than in the high-AAPR group (HR = 2.49, 95% CI: 1.67 to 3.71, P < 0.001, I2 = 84.3%; HR = 2.59, 95% CI: 1.55 to 4.35, P < 0.001, I2 = 80.3%). For recurrence-free survival (RFS), univariate analysis revealed worse outcomes in the low-AAPR group (HR = 1.58, 95% CI: 1.18 to 2.13, P = 0.002, I2 = 0.0%). However, multivariate analysis did not establish a significant correlation between the two groups (HR = 1.25, 95% CI: 0.33 to 4.77, P = 0.740, I2 = 51.5%). Subgroup analyses by country, tumor type, treatment method, and AAPR cut-off value consistently showed that low AAPR was significantly associated with poor OS. Although publication bias was detected in the OS meta-analysis, both the trim-and-fill method and sensitivity analysis confirmed a significant association between low AAPR and poor OS. CONCLUSION: A low AAPR is associated with poorer OS in GI cancer patients. Therefore, AAPR may serve as a promising serological parameter for prognostic assessment in GI cancer patients.