Prognostic Role of Platelet to Lymphocyte Ratio in Solid Tumors: A Systematic Review and Meta-Analysis

Abstract

Background: Inflammation influences cancer development and progression. An elevated platelet to lymphocyte ratio (PLR), a marker of inflammation, has been linked to poor prognosis in several malignancies. Here, we quantify the prognostic impact of this biomarker.Methods: A systematic review of databases was conducted to identify publications exploring the association of blood PLR and overall survival (OS) in solid tumors. Data were pooled in a meta-analysis. Pooled HRs for OS by disease group and by PLR cutoff groups were computed and weighted using generic inverse-variance and random-effect modeling.Results: Twenty studies comprising 12,754 patients were assessed. Cutoffs for PLR defining risk groups ranged from 150 to 300 and were dichotomous (12 studies; group 1) or split into three groups (<150/150-300/ >300, 8 studies; group 2). Higher PLR was associated with significantly worse OS in group 1 [HR ¼ 1.87; 95% confidence interval (CI, 1.49-2.34); P < 0.001] and with a nonsignificant association in group 2 (HR per higher category ¼ 1.21; 95%CI, 0.97-1.50; P ¼ 0.10). The size of effect of PLR on OS was greater for metastatic disease (HR [group 1] ¼ 2.0; 95% CI, 1.6-2.7; HR [group 2] ¼ 1.6; 95% CI, 1.1-2.4) than for early-stage disease (HR [group 1] ¼ 1.5; 95% CI, 1.0-2.2; HR [group 2] ¼ 1.0; 95% CI, 0.8-1.3). A significant association was observed for colorectal, hepatocellular, gastroesophageal, ovarian, and pancreatic carcinoma in group 1 and for colorectal cancers in group 2.Conclusion: A high PLR is associated with worse OS in various solid tumors. Further research of its regulation and relevance in daily practice is warranted.Impact: PLR is a readily available and inexpensive biomarker with independent prognostic value in solid tumors. Cancer Epidemiol Biomarkers Prev; 23(7); 1204-12. Ó2014 AACR.

The Neutrophil to Lymphocyte Ratio has a High Negative Predictive Value for Pathologic Complete Response in Locally Advanced Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

“…In recently presented a meta-analysis, it was reported that a high NLR is associated with an adverse OS in many solid tumors (Templeton et al, 2014). This study showed no relationship between the pCR and pretreatment NLR values in locally advanced BC who received NACT.…”

Clinical significance of pre-operative neutrophil lymphocyte ratio and platelet lymphocyte ratio as prognostic factors for patients with colorectal cancer

“…Tumor cells possess the ability to manipulate platelet activity to optimize tumor growth, proliferation, survival and metastasis (29). Several studies have identified the association between a poor survival rate and elevated PLR in solid tumors (2,8,9,11,16,30). Szkandera et al revealed that an elevated PLR was significantly associated with a decreased time to recurrence and demonstrated a trend towards a decreased OS time in patients with stage II and III colon cancer that underwent curative resection (2).…”

The platelet-to-lymphocyte ratio as a predictor of patient outcomes in ovarian cancer: a meta-analysis

“…Recently, many studies have focused on hematological measurements or inflammatory factors, which are associated with the tumor microenvironment, for the diagnosis and prognosis of different cancers 6 . Previous clinical studies have confirmed that increases in the neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio (PLR), neutrophil counts, or platelet counts were associated with negative clinical pathologic characteristics, such as a higher risk of recurrence, aggressive tumor biology, and greater disease progression, in patients with various types of cancer 7,8 . Platelets may release growth factors such as transforming growth factor b (TGF-b), platelet-derived growth factor (PDGF), and vascular endothelial growth factor (VEGF), which may contribute to the growth, progression, and metastasis of the tumor by stimulating the proliferation of ovarian tumor cells 9 .…”

“…Furthermore, a reduced lymphocyte count is an indicator of a reduced immune response, and it is correlated with higher mortality in patients with OC than in healthy controls or patients with benign diseases 10 . The PLR, which is inexpensively and easily determined in routine clinical practice, was proposed to be a highly efficient and independent prognostic biomarker for many tumors 7 . Although there are several studies already published examining the relationship between PLR and cancer, the role of PLR in OC prognosis remains unclear 11 .…”