Elevated platelet to lymphocyte ratio predicts poor prognosis after hepatectomy for liver-only colorectal metastases, and it is superior to neutrophil to lymphocyte ratio as an adverse prognostic factor

Recent evidence indicates that inflammation is an essential component of pathogenesis and progression of cancer. In this study, we analysed two indexes of systemic inflammation, the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), with disease-free survival (DFS) and overall survival (OS) in liver-only colorectal metastases treated with liver resection following neoadjuvant chemotherapy. In this retrospective study, 140 patients were enroled. The NLR and PLR were calculated on the basis of preoperative blood cell count, and their cutoff levels were determined by applying receiver operating curve analysis. A NLR >2.4 and a PLR >150 were considered to be elevated. DFS and OS were calculated using both Kaplan-Meier and multivariate Cox regression methods. Both high NLR and high PLR were associated with decreased DFS [HR 1.55; 95 % confidence interval (CI) 1.03-2.32; P = 0.033, and HR 1.78; 95 % CI 1.19-2.67; P = 0.005, respectively] and OS (HR 2.21; 95 % CI 1.24-3.96; P = 0.007, and HR 2.90; 95 % CI 1.61-5.21; P < 0.001, respectively) in univariate analysis, but only PLR remained significant in multivariate analysis for both DFS and OS (HR 1.68; 95 % CI 1.04-2.71; P = 0.034, and HR 2.17; 95 % CI 1.09-4.32; P = 0.027, respectively). When we divided patients into three groups (group 1: normal both NLR and PLR; group 2: high NLR or high PLR; group 3: high both NLR and PLR), the five-year DFS and OS rates for these groups were 43, 26, 9 % (P = 0.004) and 73, 59, 34 % (P < 0.001), respectively. In this study, we indicate that preoperative PLR is superior to preoperative NLR as an adverse prognostic factor in patients who undergo liver resection for liver-only colorectal metastases.