LAUSR

Introduction In this meta-analysis, we analyzed retrospective cohort studies that assessed the prognostic potential of the pretreatment lymphocyte-to-monocyte ratio (LMR) among patients with ovarian cancer (OC). Materials and methods We comprehensively searched electronic databases, including PubMed and Embase, from inception through October 2018. A random-effects model was used to calculate pooled HRs and their 95% CIs for overall survival (OS) and progression-free survival (PFS). The low LMR group was treated as the reference group. Results Twelve studies, including 3,346 OC cases at baseline, were included. Overall, our results indicated that LMR was positively associated with both OS (HR: 1.85, 95% CI: 1.50–2.28, P<0.001; I2=76.5%) and PFS (HR: 1.70, 95% CI: 1.49–1.94, P<0.001; I2=24.4%) among OC patients. Stratified analyses indicated that, for OS, the LMR’s protective effect was more evident in studies conducted among younger patients (<55 years) than in those conducted among older patients (≥55 years; P for interaction =0.017), which was confirmed by meta-regression analysis (P=0.004). Conclusion This study suggested that a higher pretreatment LMR level was associated with a favorable prognosis among OC patients. Future large-scale prospective clinical trials are needed to confirm the prognostic value of LMR among OC patients.