Lymphocyte-to-monocyte ratio prior to radioiodine ablation in low- and intermediate-risk, papillary thyroid cancer.

Abstract

We aimed to investigate inflammation indices based on preablation hematological parameter of the lymphocyte-to-monocyte ratio (LMR) to predict the clinical outcome in papillary thyroid cancer (PTC) patients with low- and intermediate-risk stratification. This retrospective study analyzed 772 patients with low- and intermediate-risk PTC who underwent total thyroidectomy followed by radioiodine therapy between July 2005 and July 2009 with a median of 10 years. Kaplan-Meier statistics were used to test differences in recurrence-free survival (RFS) between groups based on the optimal cutoff point of biomarkers identified using receiver operating characteristic curves. With an optimal cutoff point of 7.05, 215 patients (29.8%) were classified as having low LMR and 557 patients (71.2%) were classified as having high LMR. High LMR was significantly associated with a prolonged RFS (hazard ratio [HR]: 2.048, 95% confidence interval [CI]: 1.062-4.359, p = 0.001). Multivariate analysis showed that low LMR (HR = 2.035, 95% CI: 1.011-4.095, p = 0.012), tumor size over 2 cm (HR = 2.762, 95% CI: 1.303-5.852, p = 0.008), and high preablative simulated thyroglobulin level over 10 ng/ml (HR = 7.826, 95% CI: 2.353-26.033, p < 0.001) were independent prognostic markers for worse RFS in the enrolled PTC patients. LMR at the time of radioiodine therapy has comparable predictor for the clinical outcome with both tumor size and preablative simulated thyroglobulin level in low- to intermediate-risk PTC patients.