Pretreatment hematologic markers as prognostic factors in patients with nasopharyngeal carcinoma: A systematic review and meta-analysis

Abstract

Background: Pretreatment hematologic parameters of the inflammatory response, including lymphocyte, neutrophil, and platelet counts, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio, and platelet-to-lymphocyte ratio, have emerged as prognostic factors for patients with cancer. This systematic review and meta-analysis aimed to summarize the association between the hematologic markers and prognosis of nasopharyngeal carcinoma (NPC).

Methods: A systematic search of PubMed, Google Scholar, MEDLINE, EMBASE, Web of Science, and the Cochrane Library was conducted up to April 2016. Hazard ratios (HRs) with 95% confidence intervals (95% CIs) were extracted and synthesized to examine prognostic outcomes including cancer-specific survival (CSS), overall survival (OS), progression-free survival (PFS), distant metastasis-free survival, and local relapse-free survival (LRFS).

Results: Fourteen studies comprising 11,651 NPC patients were ultimately included, and all eligible studies were conducted in East Asia. The OS, CSS, PFS, distant metastasis-free survival, and LRFS risks differed among patients according to hematologic marker levels. All of the parameters were associated with prognostic outcomes in patients with NPC. NLR and lymphocyte counts were most commonly reported. A high NLR was significantly associated with poor NPC prognosis (pooled HR 1.42, 95% CI 1.21-1.67 for CSS; pooled HR 1.77, 95% CI 1.41-2.23 for OS; pooled HR 1.67, 95% CI 1.36-2.06 for PFS; pooled HR 1.64, 95% CI 1.15-2.34 for LRFS). High lymphocyte count indicated favorable NPC prognosis (pooled HR 0.72, 95% CI 0.64-0.81 for OS; pooled HR 0.71, 95% CI 0.56-0.91 for PFS).

Conclusions: Meta-analysis indicated that NLR and lymphocyte counts could be prognostic predictors in NPC for East Asian population. Patients with a high NLR or low lymphocyte count had poor prognosis. However, due to the limitation of included population, the conclusion was limited to East Asian patients only.

Figure 1

Literature screening flowchart.

Figure 2

Forest plot and meta-analysis for relationship between pretreatment NLR and CSS, OS, PFS, and LRFS in patients with NPC. (A) Forest plot of the pooled analysis of NLR and CSS. (B) Forest plot of the pooled analysis of NLR and OS. (C) Forest plot of the pooled analysis of NLR and PFS. (D) Forest plot of the pooled analysis of NLR and LRFS. CSS = cancer-specific survival, LRFS = local relapse-free survival, NLR = neutrophil-to-lymphocyte ratio, NPC = nasopharyngeal carcinoma, OS = overall survival, PFS = progression-free survival.

Figure 3

Forest plot and meta-analysis for relationship between pretreatment lymphocyte counts and OS, PFS, and LRFS in patients with NPC. (A) Forest plot of the pooled analysis of lymphocyte counts and OS. (B) Forest plot of the pooled analysis of lymphocyte counts and PFS. (C) Forest plot of the pooled analysis of lymphocyte counts and LRFS. LRFS = local relapse-free survival, NPC = nasopharyngeal carcinoma, OS = overall survival, PFS = progression-free survival.

Figure 4

Funnel plots based on prognostic value of NLR and lymphocyte counts. (A) Funnel plot based on the pooled analysis of NLR and OS. (B) Funnel plot based on the pooled analysis of NLR and PFS. (C) Funnel plot based on the pooled analysis of lymphocyte counts and OS. (D) Funnel plot based on the pooled analysis of lymphocyte counts and PFS. NLR = neutrophil-to-lymphocyte ratio, OS = overall survival, PFS = progression-free survival.