L-T3 preparation for whole-body scintigraphy: a randomized-controlled trial

• Published in: Clinical endocrinology (Oxford) Vol. 67; no. 6; pp. 839 - 844
• Main Authors: Leboeuf, Rébecca, Perron, Patrice, Carpentier, André C., Verreault, Jean, Langlois, Marie-France
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.12.2007; Blackwell
• Subjects: Adult; Biological and medical sciences; Double-Blind Method; Endocrinopathies; Female; Fundamental and applied biological sciences. Psychology; Humans; Hyperthyroidism - blood; Hyperthyroidism - drug therapy; Hypothyroidism - blood; Hypothyroidism - drug therapy; Male; Medical sciences; Middle Aged; Radionuclide Imaging; Thyroid Neoplasms - diagnostic imaging; Thyroid Neoplasms - drug therapy; Thyrotropin - blood; Thyroxine - blood; Thyroxine - therapeutic use; Treatment Outcome; Triiodothyronine - blood; Triiodothyronine - therapeutic use; Vertebrates: endocrinology; Radionuclide study; Randomization; Preparation; Randomised controlled trial; Thyroid hormone; Medical imagery; Clinical trial; Triiodothyronine; Whole body; Scintigraphy; Endocrinology
• ISSN: 0300-0664; 1365-2265; 1365-2265
• DOI: 10.1111/j.1365-2265.2007.02972.x

Summary Background  Patients with thyroid cancer often need whole‐body scintigraphy (WBS) under TSH stimulation after 4–6 weeks withdrawal from levothyroxine (L‐T4). Patients often become severely hypothyroid with impaired quality of life. Liothyronine (L‐T3) substitution is used empirically to prepare patients; however, no data exist to prove its benefit. Objectives  To compare the hypothyroid state in patients receiving either placebo or L‐T3 following L‐T4 withdrawal and to evaluate the time needed for adequate TSH elevation in preparation for WBS. Methods  At the time of L‐T4 withdrawal, patients were randomized to receive L‐T3 (50 µg qd) or placebo for 3 weeks, after which treatment was stopped. A validated evaluation of hypothyroidism (Billewicz score) was administered in a double‐blind fashion every 2 weeks until the WBS. TSH, fT4 and fT3 were measured weekly. Results  A total of 20 patients were randomized between September 2003 and May 2005. There was no difference in the Billewicz score at any time between the two groups. Before WBS, both groups were profoundly hypothyroid. TSH at time of WBS was similar in both groups. The time needed to reach a TSH level of more than 30 mUI/l was longer in L‐T3 group (mean ± SD: 32 ± 4 days vs. 17 ± 9 days in placebo group, P = 0·006). Conclusion  Preparation for WBS with L‐T3 does not prevent profound hypothyroidism and delays TSH elevation required for WBS. L‐T4 withdrawal alone for 2–3 weeks is simpler and sufficient to allow TSH to reach a level of more than 30 mUI/l in the majority of patients without increasing morbidity from hypothyroidism.