Haematologic biomarkers and survival in gallbladder cancer: a systematic review and meta-analysis

Background: Gallbladder cancer is a rare malignancy characterised by poor survival with lack of durable response to treatment. Thus, novel biomarkers are needed to prognos-ticate patients. This systematic review and meta-analysis sought to examine the role of neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, platelet count (PC) and serum immune inflammation index in predicting the survival of patients with gallbladder cancer. Materials and methods: A systematic search was done using PubMed, Cochrane, Clinical-Trials.gov and Google Scholar for articles published from inception until 8 February 2022. Hazard ratios (HR) with 95% confidence intervals (CI) were pooled and subgroup analyses were conducted according to treatment, region and cut-offs. The primary outcome of interest was overall survival (OS). Data were summarised using RevMan version 5.4. Results: Twenty studies comprising 5,183 patients were included in the analysis. High neutrophil-lymphocyte ratio (HR 1.72, 95% CI 1.47-2.02), platelet-lymphocyte ratio (HR 1.51, 95% CI 1.33-1.72), monocyte-lymphocyte ratio (HR 1.96, 95% CI 1.46-1.64), PC (HR 1.20, 95% CI 1.02-1.40) and serum inflammation index (HR 1.73, 95% CI 1.36-2.18) were all associated with worse survival. The association was consistent across most sub-groups on race and cut-offs with a trend towards poor survival for PC above 252.5. Conclusion: High neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, monocyte-lymphocyte ratio, PC and SII are associated with worse OS in gallbladder cancer and are potential biomarkers for prognostication. Prospective studies are recommended to further evaluate their use.