The predictive value of dynamic monitoring of peripheral blood lymphocyte to monocyte ratio in patients with extranodal NK/T cell lymphoma

Background: To investigate the value of dynamic monitoring peripheral blood lymphocyte-to-monocyte (LMR) ratio in evaluating the treatment response and prognosis of patients with extranodal NK/T cell lymphoma (ENKTL).

Methods: A total of 148 patients with ENKTL were retrospectively analyzed in the Affiliated Tumor Hospital of Zhengzhou University between March 2012 and March 2018. The optimal cut-off value of LMR was determined using the receiver operating characteristic curve (ROC) method, then patients were divided into low LMR group and high LMR group. The LMR level was dynamically measured at various time points, and the relationships between LMR and therapeutic response, and survival were analyzed.

Results: The complete remission rate (CR) was 85.7% in patients with high LMR at diagnosis, which was remarkably higher than that of patients with low LMR at diagnosis (64.9%) (P = 0.009). The 5-year overall survival (OS) and progression-free survival (PFS) were 49.28% and 44.89% in the low LMR group, respectively; 5-year OS and PFS in the high LMR group were 84.50% and 67.12%, respectively, significantly longer (P values were < 0.001 and 0.034, respectively). The OS and PFS of patients with elevated LMR after treatment were longer than those with decreased LMR after treatment (all P values < 0.05). The LMRs at relapse were significantly lower in both high and low LMR groups than those of the last follow-up (P values were 0.001 and 0.016, respectively). Univariate and multivariate analysis demonstrated that low LMR was an independent risk factor for poor prognosis in ENKTL patients (P values were < 0.001 and 0.009, respectively).

Conclusions: Lymphocyte to monocyte ratio can be used as an indicator of treatment response, prognosis and recurrence in patients with ENKTL. Low LMR before and after treatment is a poor prognostic factor.