Immunomodulatory Effects of Omega-3 Fatty Acids in Patients with Differentiated Thyroid Cancer Before or After Radioiodine Ablation

Thyroid cancer and radioactive iodine (RAI) ablation for postsurgical management may lead to uncontrolled inflammation. This study was intended to assess the prophylactic and therapeutic immunomodulatory effects of omega-3 fatty acids in patients with differentiated thyroid cancer (DTC). A total of 85 patients with DTC were allocated into two groups based on RAI dosage after thyroidectomy. Patients in each group were randomly distributed into three subgroups: G1 with RAI ablation only, G2 treated with omega-3 for 30 days before RAI ablation, and G3 treated with omega-3 for 30 days after RAI ablation. Fifteen healthy individuals were included as controls. Serum cytokine levels including IL-2, IL-4, IL-5, IL-6, IL-9, IL-10, IL-13, IL-17A, IL-17F, IL-21, IL-22, TNF-α and IFN-γ were determined by cytometric bead assay. IL-4, IL-6, IL-21 and IL-22 levels in patients with DTC were higher than in the healthy controls. Regardless of RAI dosage, IL-6 showed an increasing trend after RAI ablation. IL-4, IL-22, and IL-17A remained at considerably higher levels than in the healthy controls after RAI ablation. Within-group comparisons showed a significant reduction in Th1+Th17/Th2+Th22 ratio in G2 patients 1 week after RAI ablation. Between-group comparisons showed increased IL-10 levels in G3 compared with G1 patients one week after high-dose RAI ablation. In G3, Th1+Th17/Th2+Th22 and Th1+Th17/Th2+Th9+Th22 ratios were remarkably lesser than in G2 patients 1 month after intermediate-dose RAI ablation. Our results showed better anti-inflammatory effects of omega-3 when it was used therapeutically after RAI ablation in patients with DTC than when it was used prophylactically before RAI.