A Low Neutrophil to Lymphocyte Ratio Before Preoperative Chemotherapy Predicts Good Outcomes After the Resection of Colorectal Liver Metastases.

BACKGROUND: The neutrophil to lymphocyte ratio (NLR) is a marker of inflammation and is associated with poor outcomes. We aimed to evaluate the role of the pretreatment NLR in predicting the outcomes after preoperative chemotherapy in patients with colorectal liver metastases (CRLM). METHODS: A retrospective review was performed for 183 patients with CRLM. The NLR was measured before chemotherapy, and a receiver operating characteristic (ROC) curve was used to estimate the cutoff value. Logistic regressions were applied to analyze potential predictors of the pathological response. The Cox proportional hazard method was used to analyze survival. RESULTS: The pre-chemotherapy NLR was 2.4 ± 1.1, whereas the post-chemotherapy NLR was 2.1 ± 1.6 (p < 0.001). The pretreatment NLR of 2.3 was a significant predictive marker for the pathological response. The pathological response rates were 67.1% in the patients with an NLR ≤ 2.3 and 48.1% in patients with an NLR > 2.3 (p = 0.01). Multivariate analysis revealed that the factors independently associated with pathological responses were a low pretreatment NLR (p = 0.043), radiological response to chemotherapy (p < 0.001), first-line chemotherapy (p = 0.001), and targeted therapy (p = 0.002). The median overall survival (OS) and recurrence-free survival (RFS) were worse in the increased NLR cohort than in the low NLR cohort (OS: 31.1 vs. 43.1 months, p = 0.012; RFS: 6.5 vs. 9.4 months, p = 0.06). According to multivariate analyses, a high pretreatment NLR was a significant predictor for both worse OS (HR = 2.43, 95%CI = 1.49-3.94, p < 0.001) and RFS (HR = 1.53, 95%CI = 1.08-2.18, p = 0.017). CONCLUSIONS: An increased pretreatment NLR was a significant predictor of a poor pathological response and worse prognosis after preoperative chemotherapy. The NLR is a simple biomarker for assessing chemotherapy efficacy.