Low Lymphocyte-to-Monocyte Ratios Are Associated with Poor Overall Survival in Anaplastic Thyroid Carcinoma Patients

Background: The lymphocyte-to-monocyte ratio (LMR), which reflects the tumor-infiltrating immune cell status and host immunity, has been reported as a prognostic marker in various cancers. The aim of the present study was to evaluate the role of the LMR as a prognostic marker in predicting the survival of patients with anaplastic thyroid carcinoma (ATC). Methods: This study retrospectively included 35 ATC patients with available complete blood cell count data. The primary outcome was the overall survival (OS) of patients with ATC. Results: There were no significant differences between the LMR of the baseline and that of the follow-up complete blood cell count data (p = 0.53). The patients were divided into two groups based on their baseline LMR: a low LMR group (n = 23, 66%) and a high LMR group (>= 4; n = 12, 34%). The proportion of cervical lymph node metastasis in the low LMR group was significantly higher than that in the high LMR group (p = 0.021). The OS curves were significantly different based on the LMR values, and the median OS of the low and high LMR groups were 3.0 and 9.5 months, respectively (p = 0.004). In multivariate analysis, a low LMR was also an independent risk factor for all-cause mortality in patients with ATC (hazard ratio = 2.55 [confidence interval 1.08-6.00], p = 0.032) after adjusting for sex, tumor size, and distant metastasis. Conclusions: A low LMR is associated with poor survival in patients with ATC. The LMR could be a simple and stable prognostic biomarker reflecting host immunity in patients with ATC. Further studies are needed to confirm the prognostic role of the LMR in ATC.