Prognostic role of Glasgow prognostic score in patients with colorectal cancer: evidence from population studies

Glasgow prognostic score (GPS) has been reported to be an indicator of prognosis for various cancers. However, the relationship between GPS and colorectal cancers (CRC) remains unclear. A comprehensive search of Pubmed, Embase, Cochrane library, Web of Science, ChinaInfo and Chinese National Knowledge Infrastructure was performed to identify eligible studies, from which the risk of overall survival (OS) and cancer-specific survival (CSS) were extracted. A random-effect model was adopted to combine hazard ratio (HR) and 95% confidence interval (CI). 25 articles with a total of 5660 participants were included. The pooled results indicated that elevated GPS was associated with poor OS (HR = 2.83, 95%CI: 2.00–4.00, P < 0.01) and CSS (HR = 1.94, 95%CI: 1.51–2.49, P < 0.01). This correlation was confirmed both in primary operable and advanced inoperable patients. Increased GPS was also closely related to advanced tumour-node-metastasis (TNM) stage (odds ratio [OR] = 1.44, 95% CI: 1.010–2.065, P < 0.05) and elevated level of serum carcinoembryonic antigen (OR = 2.252, 95% CI: 1.508–3.362, P < 0.01). Subgroup analysis revealed a significant association between high GPS and poor survival outcome according to the factors of sample size, study of region and cut-off value of GPS level. These findings suggest that GPS may serve as a reliable predictive index for patients with CRC.