Neutrophil-to-lymphocyte ratio predicts survival of patients with rectal cancer receiving neo-adjuvant chemoradiation followed by radical resection: a meta-analysis

Neutrophil-to-lymphocyte ratio is suggested as a prognostic and predictive factor for patients with rectal cancer. The purpose of the current meta-analysis is to evaluate the relationship between neutrophil-lymphocyte ratio (NLR) and the outcome of patients, with rectal cancer receiving chemoradiation and surgery.
A systematic review on two databases and a selection of studies were done. Thereafter, two meta-analyses were performed, evaluating the relationship of baseline NLR with overall survival (OS) and disease-free survival (DFS).
Thirty-one retrospective studies were selected. Twenty-six studies have documented a significant relationship of NLR to OS (HR 2.05, CI 1.66–2.53), whereas 23 studies have reported a weaker but significant relationship of NLR to DFS (HR 1.78, CI 1.49–2.12). Among the moderator variables, a possible effect for age and sex on the relationship of NLR with DFS is suggested.
Baseline NLR >3 is a simple and reproducible prognostic factor, with a more consistent effect in the elderly. It could be a reliable variable to support clinicians in defining personalized treatment strategies, even though a standardization of the cutoff and a better characterization among microsatellite unstable rectal tumors are necessary.

中性粒细胞与淋巴细胞比值(Neutrophil-to-lymphocyte ratio, NLR)被认为是直肠癌患者的预后及预测因子。本项荟萃分析旨在探讨接受放化疗联合手术治疗的直肠癌患者的NLR与临床结局之间的关联。
研究首先通过两大数据库开展系统回顾并筛选相关研究，随后开展两项荟萃分析，分别评估基线NLR与总生存期(Overall Survival, OS)及无病生存期(Disease-Free Survival, DFS)的关联。
最终纳入31项回顾性研究。其中26项研究证实NLR与OS存在显著关联(风险比(Hazard Ratio, HR)=2.05，置信区间(Confidence Interval, CI)=1.66~2.53)，另有23项研究显示NLR与DFS亦存在较弱但仍具有统计学意义的关联(HR=1.78，CI=1.49~2.12)。在调节变量分析中，提示年龄与性别可能对NLR与DFS的关联存在影响。
基线NLR＞3是一项简便且可重复的预后因子，在老年患者中其预后预测效果更为稳定。尽管仍需统一临界值阈值，并进一步明确微卫星不稳定型直肠癌的相关特征，但该指标可作为辅助临床医师制定个体化治疗策略的可靠变量。