Is a four-week hormone suspension necessary for thyroid remnant ablation in low and intermediate risk patients? A pilot study with quality-of-life assessment

Radioiodine therapy (RIT) is a complementary treatment to total thyroidectomy in differentiated thyroid cancer (DTC) patients. High levels of thyroid-stimulating hormone (TSH) are usually required in clinical practice to increase RIT efficacy. Suspension of levothyroxine hormone for weeks is usually necessary, greatly impacting patients' quality of life. Patients with DTC of low or intermediate-risk were divided into two groups - one where levothyroxine was suspended for 4-5 weeks and a TSH ≥ 30 mUI/L was required for radioiodine administration (group 1), and another where levothyroxine was suspended for two weeks only (group 2). The RIT efficacy was compared between the groups. The absorbed dose in the cervical region after 24 hours was also calculated and correlated with TSH. The quality of life was also accessed with the EORTC questionnaire. Thirty-one patients were included in this study (14 in group 1 and 17 in group 2), with a mean age of 45.7 ± 10.6 years and 29 (93.5%) females. The mean TSH level for group 1 was 67.0 ± 35.6 UI/ml, and for group 2 was 31.3 ± 29.4 UI/ml. After six months, the successful RIT frequency was 66.6% for group 1 and 73.3% for group 2. Patients from group 2 showed better quality of life. TSH level ≥ 30 mUI/L is not critical for the success of RIT in patients with low or intermediate risk DTC. A two-week suspension of thyroid hormone appears to meet similar RIT needs, providing a better quality of life.