To validate the simplest approach to preparing patients with differentiated thyroid carcinoma (DTC) for 131I-administration (131I-A), minimizing the impact of hypothyroidism.Design
Ninety patients with DTC were enrolled in the study. Sixty (Group A) underwent total thyroidectomy (TT); L-T4 was not administered in preparation for 131I-A planned for 3 weeks later. Thirty patients (Group B) with previous TT and 131I-A stopped L-T4 in preparation for clinical evaluation, including whole-body scanning (WBS)/radioiodine therapy during thyrotrophin (TSH) stimulation planned for 3 weeks (or more) later.Measurements
Thyrotrophin was measured the day before TT for group A, during L-T4 for group B (baseline-time 1) and then every week until it reached ≥30 mIU/l (time 2). Quality of life (QoL) was evaluated by Billewicz index.Results
At week 3, 100% of patients in group A and 56·6% of group B exceeded TSH > 30 mIU/l. In group B, the cut-off was achieved in four patients at the fourth week (TSH 38·6 ± 8·7 mIU/l), in 3 at the fifth (53·2 ± 3) and in 6 at the sixth (42·3 ± 6·1). From time 1 to time 2, total QoL scores were less affected in group A (percentage decrease: 105%) than in group B (218%). At time 2, the total score was >+19 in group A in 46 patients and in 30 in group B. In group A, TSH levels in the higher tertile of QoL (61 ± 6 mIU/l) were not different from those in the lower tertile (62·3 ± 11·1)(P > 0·1); similar results were seen in group B (69·3 ± 13·3 vs 62·9 ± 13·1)(P > 0·1). There was a positive correlation between the time to obtain TSH ≥ 30 mIU/l and total QoL scores.Conclusions
Quality of life scores were not affected by thyrotrophin was measured the day before TT levels as absolute values. A longer time to obtain TSH ≥ 30 mIU/l was positively correlated with worse scores of QoL. We suggest 3 weeks without therapy can be used as an easy schedule in patients who undergo TT for DTC.