Prognostic significance of neutrophil-to-lymphocyte ratio in diffuse large B-cell lymphoma: A meta-analysis

BACKGROUND: Neutrophil-to-lymphocyte ratio (NLR) has been investigated as a prognostic marker in patients with diffuse large B-cell lymphoma (DLBCL); however, the results remain controversial. This study aimed to explore the association between NLR and survival outcomes and clinicopathological factors in DLBCL. METHODS: Relevant studies were retrieved by searching PubMed, Embase, Web of Science, and China National Knowledge Infrastructure (CNKI) databases. The last search was updated on February 17, 2017. Hazard ratios (HRs) and odds ratios (ORs) and their 95% confidence intervals (CIs) were used as effective measures in the meta-analysis. Random-effects models and fixed-effects models were used for analyses. Meta-regression was performed. Publication bias was assessed using Begg’s test. Stata version 12.0 was used for all analyses. RESULTS: A total of 9 studies with 2297 patients were included in the meta-analysis. The pooled results showed that NLR was a significant indicator for poor overall survival (OS) (HR = 1.84, 95% CI = 1.52–2.22, p<0.001) and poor progression-free survival (PFS) (HR = 1.64, 95% CI = 1.36–1.98, p<0.001). NLR remained a significant biomarker for OS and PFS regardless of location, sample size or cut-off value. In addition, high NLR was also associated with Ann Arbor stage (OR = 2.09, 95% CI = 1.14–3.81, p = 0.017), lactate dehydrogenase level (OR = 2.74, 95% CI = 1.16–6.46, p = 0.021), extranodal disease (OR = 1.63, 95% CI = 1.06–2.52, p = 0.027), and International Prognostic Index score (OR = 2.44, 95% CI = 1.03–5.08, p = 0.043). However, NLR was found to have no significant association with sex (OR = 0.89, 95% CI = 0.71–1.11, p = 0.29), age (OR = 1.18, 95% CI = 0.94–1.48, p = 0.152), European Cooperative Oncology Group performance status score (OR = 1.78, 95% CI = 0.71–4.46, p = 0.217), or presence of B symptoms (OR = 1.56, 95% CI = 0.7–3.48, p = 0.278). CONCLUSION: In conclusion, our meta-analysis demonstrated that NLR has a strong association with worse OS and PFS in patients with DLBCL. NLR could be recommended as an inexpensive prognostic biomarker in DLBCL.