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

• Published in: Cancer epidemiology, biomarkers & prevention Vol. 23; no. 7; pp. 1204 - 1212
• Main Authors: TEMPLETON, Arnoud J, ACE, Olga, MCNAMARA, Mairéad G, AL-MUBARAK, Mustafa, VERA-BADILLO, Francisco E, HERMANNS, Thomas, SERUGA, Boštjan, OCANA, Alberto, TANNOCK, Ian F, AMIR, Eitan
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Association for Cancer Research 01-07-2014
• Subjects: Biological and medical sciences; Humans; Lymphocyte Count; Medical sciences; Multiple tumors. Solid tumors. Tumors in childhood (general aspects); Neoplasms - blood; Neoplasms - mortality; Platelet Count; Prognosis; Tumors; Solid tumor; Platelet; Cancerology; Prognosis; Systematic review; Ratio; Malignant tumor; Lymphocyte; Cancer; Metaanalysis
• ISSN: 1055-9965; 1538-7755
• DOI: 10.1158/1055-9965.epi-14-0146

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.
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.
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 = 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 = 1.21; 95%CI, 0.97-1.50; P = 0.10). The size of effect of PLR on OS was greater for metastatic disease (HR[group 1] = 2.0; 95% CI, 1.6-2.7; HR[group 2] = 1.6; 95% CI, 1.1-2.4) than for early-stage disease (HR[group 1] = 1.5; 95% CI, 1.0-2.2; HR[group 2] = 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.
A high PLR is associated with worse OS in various solid tumors. Further research of its regulation and relevance in daily practice is warranted.
PLR is a readily available and inexpensive biomarker with independent prognostic value in solid tumors.