The clinical use of the platelet/lymphocyte ratio and lymphocyte/monocyte ratio as prognostic predictors in colorectal cancer: a meta-analysis

// Ya-Huan Guo 1, 2, * , Hai-Feng Sun 1, 3, * , Yan-Bing Zhang 2 , Zi-Jun Liao 1, 2 , Lei Zhao 4 , Jie Cui 5 , Tao Wu 1 , Jian-Rong Lu 1 , Ke-Jun Nan 1 , Shu-Hong Wang 1 1 Department of Medical Oncology, The First Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China 2 First Department of Medical Oncology, Shaanxi Provincial Tumor Hospital, Xi’an, P.R. China 3 Third Department of Medical Oncology, Shaanxi Provincial Tumor Hospital, Xi’an, P.R. China 4 Department of Molecular Physiology and Biophysics, Holden Comprehensive Cancer Center, University of Iowa Carver College of Medicine, Iowa City, IA, USA 5 Department of Oncology, Yan’an University Affiliated Hospital, Yan’an, P.R. China 6 Third Department of Pathology, Shaanxi Provincial Tumor Hospital, Xi’an, P.R. China * These authors share the first authorship Correspondence to: Ke-Jun Nan, email: nankj@163.com Shu-Hong Wang, email: wsh2003@126.com Keywords: platelet/lymphocyte ratio, lymphocyte/monocyte ratio, colorectal cancer, prognostic predictor, inflammatory markers Received: August 23, 2016     Accepted: December 28, 2016     Published: February 14, 2017 ABSTRACT Background: Conflicting evidence exists regarding the effects of platelet/lymphocyte ratio (PLR) and lymphocyte/monocyte ratio(LMR) on the prognosis of colorectal cancer (CRC) patients. This study aimed to evaluate the roles of the PLR and LMR in predicting the prognosis of CRC patients via meta-analysis. Methods: Eligible studies were retrieved from the PubMed, Embase,andChina National Knowledge Infrastructure (CNKI) databases, supplemented by a manual search of references from retrieved articles. Pooled hazard ratios (HR) with 95% confidence intervals (95% CI) were calculated using the generic inverse variance and random-effect model to evaluate the association of PLR and LMR with prognostic variables in CRC, including overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS). Results: Thirty-three studies containing 15,404 patients met criteria for inclusion. Pooled analysis suggested that elevated PLR was associated with poorer OS (pooled HR = 1.57, 95% CI: 1.41 – 1.75, p < 0.00001, I 2 =26%) and DFS (pooled HR = 1.58, 95% CI: 1.31 – 1.92, p < 0.00001, I 2 =66%). Conversely, high LMR correlated with more favorable OS (pooled HR = 0.59, 95% CI: 0.50 – 0.68, p < 0.00001, I 2 =44%), CSS (pooled HR = 0.54, 95% CI: 0.40 – 0.72, p < 0.00001, I 2 =11%) and DFS (pooled HR = 0.82, 95% CI: 0.71– 0.94, p =0.005, I 2 =29%). Conclusions: Elevated PLR was associated with poor prognosis, while high LMR correlated with more favorable outcomes in CRC patients. Pretreatment PLR and LMR could serve as prognostic predictors in CRC patients.