Preoperative lymphocyte-to-monocyte ratio predicts breast cancer outcome: A meta-analysis

Aim: To assess the prognostic value of the preoperative lymphocyte-to-monocyte ratio (LMR) in patients with breast cancer (BC). Methods: Relevant studies were systematically retrieved from the online Cochrane, MEDLINE, EMBASE and CNKI databases published until February 2018. The end points were overall survival (OS), disease-free survival (DFS), and clinicopathological parameters. Meta-analysis was performed using hazard ratios (HRs) or odds ratios (ORs) and their 95% confidence intervals (CIs) as effect measures. Results: Ten studies with 5667 individuals were included. The synthesized analysis demonstrated that that low LMR was significantly associated with poor OS (HR: 0.65, 95% CI: 0.47-0.90, p = .009) and DFS (HR: 0.60, 95% CI: 0.49-0.74, p < .001). Subgroup analyses revealed that the negative prognostic impact of low LMR on OS outcomes remained substantial in Asian populations, triple-negative patients, and patients with non-metastatic and mixed stage. However, low LMR was not significantly related to clinicopathological features. Conclusion: The preoperative LMR might be a predictive factor of poor prognosis for BC patients.