RESUMEN
BACKGROUND: High pretreatment level of D-dimer in small cell lung cancer (SCLC) is commonly encountered, but the impact of high pretreatment D-dimer level on the prognosis of SCLC patients remains undetermined. Therefore, we conducted this meta-analysis focusing specifically on the prognostic value of high pretreatment D-dimer level in SCLC patients comprehensively. METHODS: We searched systematically in PubMed, Embase, and Web of Science for relevant studies published before January 28, 2019. Outcomes including 1-year overall survival (OS), progression-free survival (PFS) rates, and hazard ratios (HRs) of OS and PFS from multivariate analysis were extracted and analyzed. RESULTS: A total of 5 cohort studies consisting of 813 SCLC patients (473 patients with high pretreatment level of D-dimer and 340 with normal level of D-dimer) were finally included for meta-analysis. We found that patients with high pretreatment level of D-dimer had significantly shorter 1-year OS (47.6% vs 79.9%; fixed effects: risk ratio [RR]â=â2.506; 95% confidence interval [CI]â=â[1.948, 3.224]; Pâ<â.001) and PFS (15.8% vs 34.0%; random effects: RRâ=â1.294; 95% CIâ=â[1.060, 1.579]; Pâ=â.011) rates than those with normal level of D-dimer. Moreover, high pretreatment D-dimer level was further proved to remain as an unfavorable predictor of OS (fixed effects: HRâ=â1.865; 95% CIâ=â[1.469, 2.367]; Pâ<â.001; I2â=â7.6%) and PFS (fixed effects: HRâ=â1.513; 95% CIâ=â[1.183, 1.936]; Pâ=â.001; I2â=â0.0%) in patients with SCLC. CONCLUSION: High pretreatment level of D-dimer was found to be an independent unfavorable prognostic factor in SCLC patients. However, more studies with sufficient adjustment for confounding factors are encouraged to confirm our conclusions.