An Elevated Platelet-to-Lymphocyte Ratio Predicts Poor Prognosis and Clinicopathological Characteristics in Patients with Colorectal Cancer: A Meta-Analysis.

Background. The aims of this study were to evaluate the clinicopathological and prognostic values of platelet-to-lymphocyte ratio (PLR) in colorectal cancer (CRC). Methods. The PubMed and Embase databases and the references of relevant studies were systematically searched. This study was performed with hazard ratios (HRs) and odd ratios (ORs) with corresponding 95% confidence intervals (CIs) as effect measures. Results. Our results indicated that elevated PLR was associated with poor overall survival (HR = 1.46, 95% CI = 1.23-1.73), disease-free survival (HR = 1.64, 95% CI = 1.17-2.30), cancer-specific survival (HR = 1.30, 95% CI = 1.12-1.51), and recurrence-free survival (HR = 1.38, 95% CI = 1.09-1.74) in CRC. For the clinicopathological characteristics, our results indicated that there were differences in the rate of elevated PLR between stages III/IV and I/II groups (OR = 1.38, 95% CI = 1.01-1.88), pT3/T4 and pT1/T2 groups (OR = 1.82, 95% CI = 1.03-3.20), and poor differentiation and moderate/well differentiation (OR = 2.59, 95% CI = 1.38-4.84). Conclusions. Our results indicated that elevated PLR predicted poor prognosis and clinicopathological characteristics in CRC and PLR is a convenient and low-cost blood-derived prognostic marker for CRC.