Objectives: Recent studies suggest that an elevated preoperative platelet to lymphocyte ratio (PLR) may be considered a poor prognostic biomarker in patients with colorectal cancer (CRC). The aim of this study was to evaluate the prognostic impact of PLR in patients with CRC.
Methods: We enrolled 1314 patients who underwent surgery for CRC between 2005 and 2011. Preoperative PLR level was stratified into quintiles for Kaplan-Meier analysis and multivariable Cox proportional hazard regression models.
Results: Higher PLR quintiles were significantly associated with poorer overall survival (P = 0.002). Multivariate analysis showed that PLR was an independent risk factor for overall survival (OS) (P = 0.034). Patients in PLR quintile 5 had lower overall survival than in quintile 1 (hazard ratio (HR) = 1.701, 95% confidence interval (CI): 1.267-2.282, P < 0.001). Although patients in PLR quintile 5 had significantly lower disease-free survival (DFS) than in quintile 1 (HR = 1.522, 95% CI: 1.114-2.080, P = 0.008), this association was not significant after multivariable adjustment (P = 0.075). In the subgroup analysis, PLR remained an independent factor in terms of advanced tumor stage (III, IV), male sex, carcinoembryonic antigen (≤ 5 ng/ml), age (> 65 years) and body mass index (≤ 25) (P < 0.05 for all measurements). The results remained unchanged when the PLR was analyzed as a dichotomous variable by applying different cut-off values of 150, 185, 220.
Conclusions: Elevated preoperative PLR was independently associated with an increased risk of mortality in patients with CRC. The utility of PLR may help to improve prognostic predictors.
Keywords: colorectal cancer; disease-free survival; overall survival; platelet to lymphocyte ratio; prognostic biomarker.