Background To evaluate the prognostic value of pretreatment lymphocyte counts with respect to clinical outcomes in patients with solid tumors. Methods Systematic literature search of electronic databases (Pubmed, Embase and Web of Science) up to May 1, 2018 was carried out by two independent reviewers. We included Eligible studies assessed the prognostic impact of pretreatment lymphocytes and had reported hazard ratios (HR) with 95% confidence intervals (CIs) for endpoints including overall survival (OS) and progression-free survival (PFS). Only English publications were included. Results A total of 42 studies comprising 13,272 patients were included in this systematic review and meta-analysis. Low pretreatment lymphocyte count was associated with poor OS (HR = 1.27, 95% CI 1.16-1.39, P < 0.001, I2 = 58.5%) and PFS (HR = 1.27, 95% CI 1.15-1.40, P < 0.001, I2 = 25.7%). Subgroup analysis disaggregated by cancer type indicated that low pretreatment lymphocytes were most closely associated with poor OS in colorectal cancer followed by breast cancer and renal cancer. Conclusions Low pretreatment lymphocyte count may represent an unfavorable prognostic factor for clinical outcomes in patients with solid tumors.

中文翻译：

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预处理血淋巴细胞计数在实体瘤患者中的预后作用：系统评价和荟萃分析。

背景 评估预处理淋巴细胞计数对实体瘤患者临床结果的预后价值。方法 由两名独立审稿人对截至 2018 年 5 月 1 日的电子数据库（Pubmed、Embase 和 Web of Science）进行系统文献检索。我们纳入了评估预处理淋巴细胞对预后影响的合格研究，并报告了包括总生存期 (OS) 和无进展生存期 (PFS) 在内的终点的风险比 (HR) 和 95% 置信区间 (CI)。仅包括英文出版物。结果本次系统评价和荟萃分析共纳入 42 项研究，共 13,272 名患者。低预处理淋巴细胞计数与较差的 OS（HR = 1.27, 95% CI 1.16-1.39, P < 0.001, I2 = 58.5%）和 PFS（HR = 1.27, 95% CI 1.15-1）相关。40，P < 0.001，I2 = 25.7%）。按癌症类型分类的亚组分析表明，低预处理淋巴细胞与结直肠癌的不良 OS 最密切相关，其次是乳腺癌和肾癌。结论 治疗前淋巴细胞计数低可能是实体瘤患者临床结局的不利预后因素。