Meta-analysis of multiple hematological biomarkers as prognostic predictors of survival in bladder cancer

BACKGROUND: Accumulating emerging studies have demonstrated that systemic inflammation can obviously affect tumor occurrence and progression. Nevertheless, the prognostic value of hematological inflammation biomarkers in bladder cancer is controversial. Thus, we conducted a meta-analysis to evaluate the key hematological biomarkers with various clinical outcomes in bladder cancer. METHODS: We used online databases PUBMED and EMBASE to search relevant studies published prior to August 2019. After collecting the basic characteristics and prognostic data from the studies included, overall survival (OS), cancer-specific survival (CSS) and progression-free survival (PFS) were used as primary results. Subgroup analyses were performed according to ethnicity, the number of samples, survival outcomes, the value of cut-off, follow-up time and metastasis stage. RESULTS: Thirty-three independent studies with 17,087 bladder cancer patients were added in the present analysis. The collected results showed that the increased neutrophil-to-lymphocyte ratio was associated with a poor OS (hazard ratio [HR] = 1.48, 95% confidence interval [CI]: 1.32–1.67, P < .00001), CSS (HR = 1.71, 95%CI: 1.35–2.18, P < .0001) and PFS (HR = 1.59, 95%CI: 1.38–1.83, P < .00001). Additionally, the elevated platelet-to-lymphocyte ratio was related to a poor OS (HR = 1.29, 95% CI: 1.07–1.54, P = .007), CSS (HR = 1.14, 95%CI = 0.98–1.34, P = .02) and PFS (HR = 1.2, 95%CI: 1.08–1.34, P = .0008). Moreover, a decreased lymphocyte-to-monocyte ratio was associated with a poor OS (HR = 0.77, 95% CI: 0.70–0.84, P = .001), CSS (HR = 0.76, 95%CI: 0.70–0.84). An elevated modified Glasgow prognostic score was also associated with a poor OS (HR = 2.71, 95%CI: 1.08–2.82, P = .003), CSS (HR = 1.50, 95%CI: 0.56–4.05) and PFS (HR = 1.52, 95%CI: 1.23–1.88, P = .001). CONCLUSIONS: Our study indicated that the pretreatment hematological biomarkers (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, lymphocyte-to-monocyte ratio, and modified Glasgow prognostic score) were predicative biomarkers of prognosis in bladder cancer patients. Further research is needed to conduct further prospective and multicenter studies to confirm our findings.