Urinary iodine concentration and radioactive iodine therapeutic response in patients with differentiated thyroid cancer.

Aim: Urinary iodine concentration (UIC) may assess radioactive iodine ablation. Materials & methods: According the 2015 American Thyroid Association guidelines, patients were categorized into low- to intermediate-risk or high-risk groups. The iodine concentration in the morning urine specimens was measured by the ceric ion-arsenious acid method. Results: In the low- to intermediate-risk group (113 cases), nonexcellent response (non-ER) was associated with higher UIC, higher UIC subgroups (p < 0.05), higher pre-ablative stimulated thyroglobulin levels (p < 0.01). In the high-risk group (68 cases), the non-ER rate was higher in the higher pre-ablative stimulated thyroglobulin group (p < 0.01), but not significantly different between the UIC and UIC subgroups (p > 0.05). Conclusion: The non-ER rate was related to UIC in the low- to intermediate-risk group; however, UIC did not affect the non-ER rate in the high-risk group.