Prognostic impact of preoperative lymphocyte-to-monocyte ratio in patients with colorectal cancer with special reference to myeloid-derived suppressor cells

Aims : We aimed to investigate the relationship of colorectal cancer prognosis and inflammatory parameters, including neutrophil-to-lymphocyte ratio (NLR) and lymphocyte-to-monocyte ratio (LMR), with reference to circulating myeloid-derived suppressor cells (MDSCs) in the current study. Patients and Methods : Thirty-five patients who underwent curative-intent surgery were enrolled. A receiver-operating characteristic curve (ROC) was used to assess the usefulness of candidates for prognostic factors. Recurrence-free survival (RFS) was calculated using the Kaplan-Meier method, and the candidates for prognostic factors were assessed by a Cox proportional hazard model. Results : ROC curve analyses determined cutoff values for NLR and LMR as 2.9 and 2.4, respectively. The percentage of MDSCs in patients with LMR <= 2.4 was statistically higher than in those with LMR > 2.4 (p = 0.012). The patients with LMR <= 2.4 exhibited a statistically lower RFS than those with LMR > 2.4 (p = 0.008). These results were also observed in patients with stage II + III disease. LMR was an independent prognostic factor of RFS in colorectal cancer patients (hazard ratio : 7.757, 95% confidence interval : 1.462 41.152, p = 0.016). Conclusion : Lower LMR was associated with poor prognosis in colorectal cancer patients ; where-as, higher circulating MDSCs were observed in patients with lower LMR.