Background: The lymphocyte-to-monocyte ratio (LMR) reflects tumor infiltrating immune cell status and host immunity. The LMR has been reported as a prognostic marker in various cancers including anaplastic thyroid carcinoma. The aim of the present study was to evaluate the role of LMR as a prognostic marker in patients with progressive radioiodine-refractory (RAIR) differentiated thyroid carcinoma (DTC).
Methods: We retrospectively included forty patients with progressive RAIR DTC who were treated by sorafenib and had available pre-treatment complete blood cell count (CBC) data. We assessed the response rate, progression-free survival (PFS), and overall survival (OS) according to the LMR.
Results: The patients were divided into two groups based on their pre-treatment LMR: a low LMR group (<4) (n = 22, 55%) and a high LMR group (≥ 4) (n = 18, 45%). There was no significant difference in baseline characteristics between two groups. Low LMR was associated with poor response rate and shorter disease control duration to sorafenib. The PFS curves were significantly different based on the LMR values, and the median PFS of the low and high LMR groups (P = 0.019). The OS curves were also significantly different based on the LMR values, and the median OS of the low and high LMR groups were 24.3 and 35.7 months, respectively (P = 0.015). In multivariate analysis, low LMR was an independent risk factor for all-cause mortality in patients with progressive RAIR DTC (HR, 2.64; 95% confidence interval (CI): 1.04-6.72, P = 0.041).
Conclusions: Low LMR is associated with poor response rate, PFS and OS in patients with progressive RAIR DTC who were treated by sorafenib. LMR could be a simple prognostic biomarker in patients with progressive RAIR DTC.