Neutrophil-to-lymphocyte ratio for the prognostic assessment of hepatocellular carcinoma: A systematic review and meta-analysis of observational studies

Background and aims: Neutrophil to lymphocyte ratio (NLR) is an inflammatory-based marker. A systematic review and meta-analysis was performed to explore the prognostic role of NLR in patients with hepatocellular carcinoma (HCC). Results: Overall, 598 papers were identified, of which 90 papers including 20,475 HCC patients were finally included. Low baseline NLR was significantly associated with better overall survival (HR = 1.80, 95% CI: 1.59-2.04, p < 0.00001) and recurrence-free or disease-free survival (HR = 2.23, 95% CI: 1.80-2.76, p < 0.00001). Low post-treatment NLR was significantly associated with better overall survival (HR = 1.90, 95% CI: 1.22-2.94, p = 0.004). Decreased NLR was significantly associated with overall survival (HR = 2.23, 95% CI: 1.83-2.72, p < 0.00001) and recurrence-free or disease-free survival (HR = 2.23, 95% CI: 1.83-2.72, p < 0.00001). The findings from most of subgroup meta-analyses were consistent with those from the overall meta-analyses. Materials and Methods: All relevant literatures were identified via PubMed, EMBASE, and Cochrane library databases. Hazard ratio (HR) with 95% confidence interval (95% CI) was calculated. Subgroup meta-analyses were performed according to the treatment options, NLR cut-off value ranges, and regions. Conclusions: NLR should be a major prognostic factor for HCC patients. NLR might be further incorporated into the prognostic model of HCC.