Prophylactic and therapeutic immunomodulatory effects of omega-3 fatty
acids in patients with differentiated thyroid cancer scheduled for
radioiodine ablation
Abstract
Radioactive iodine (RAI)-induced thyrocyte destruction may lead to
uncontrolled inflammation. This study was designed to evaluate the
prophylactic and therapeutic immunomodulatory effects of omega-3 fatty
acids in patients with differentiated thyroid cancer scheduled for RAI
ablation. A total of 85 patients were divided into two groups based on
radioiodine dosage after thyroidectomy: high-dose with 150 mCi and
intermediate-dose with 100 mCi. Then patients in each group were
randomly divided 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. Serum cytokine levels were
determined with the cytometric bead assay at different time points.
Within-group comparisons showed transient elevation of IL-13 after
pretreatment with omega-3, significant reductions in Th1+Th17/Th2+Th22
ratio after high-dose RAI ablation, and decreased Th1+Th17/Th2+Th22 and
Th1+Th17/Th2+Th9+Th22 ratios after intermediate-dose RAI ablation in G2.
Between-group comparisons showed that IL-10 level in G3 was
significantly higher than in G1 1 week after high-dose RAI ablation,
whereas Th1+Th17/Th2+Th22 and Th1+Th17/Th2+Th9+Th22 ratios were
significantly lower in G3 than G2 1 month after intermediate-dose RAI
ablation. However, cytokine changes 1 week and 1 month after RAI
ablation when adjusted for baseline values showed no differences among
groups. Despite observing within-group changes in some cytokines, we
found no real changes attributable to a prophylactic or therapeutic
anti-inflammatory effect of omega-3. Because of the specific effect of
radioactive iodine on thyroid cells, extensive systemic inflammation may
not be induced after RAI ablation.