CLINICAL STUDY Serum thyroglobulin and 131 I whole body scan after recombinant human TSH stimulation in the follow-up of low-risk patients with differentiated thyroid cancer Massimo Torlontano, Umberto Crocetti, Leonardo D’Aloiso, Nazario Bonfitto 1 , Anna Di Giorgio 2 , Sergio Modoni 3 , Guido Valle 3 , Vincenzo Frusciante 3 , Michele Bisceglia 4 , Sebastiano Filetti 5 , Martin Schlumberger 6 and Vincenzo Trischitta 5 Units of Endocrinology, 1 Surgery, 2 Clinical Chemistry, 3 Nuclear Medicine and 4 Pathology, Scientific Institute ‘Casa Sollievo della Sofferenza’, 71013 San Giovanni Rotondo, Foggia, Italy, 5 Department of Clinical Sciences, University ‘La Sapienza’, 00100 Rome, Italy and 6 Department of Nuclear Medicine, Institut Gustave-Roussy, 94805 Villejuif, France (Correspondence should be addressed to Massimo Torlontano; Email: endocrino@operapadrepio.it) Abstract Objective: The ‘standard’ postoperative follow-up of patients with differentiated thyroid cancer (DTC) has been based upon serum thyroglobulin (Tg) measurement and 131 I whole body scan ( 131 I-WBS) after thyroid hormone (T 4 ) treatment withdrawal. However, 131 I-WBS sensitivity has been reported to be low. Thyroid hormone withdrawal, often associated with hypothyroidism-related side effects, may now be replaced by recombinant human thyroid stimulating hormone (rhTSH). The aim of our study was to evaluate the diagnostic accuracy of 131 I-WBS and serum Tg measurement obtained after rhTSH stimulation and of neck ultrasonography in the first follow-up of DTC patients. Design: Ninety-nine consecutive patients previously treated with total thyroidectomy and 131 I abla- tion, with no uptake outside the thyroid bed on the post-ablative 131 I-WBS (low-risk patients) were enrolled. Methods: Measurement of serum Tg and 131 I-WBS after rhTSH stimulation, and ultrasound examin- ation (US) of the neck. Results: rhTSH-stimulated Tg was # 1 ng/ml in 78 patients (Tg2 ) and . 1 ng/ml (Tg+) in 21 patients, including 6 patients with Tg levels . 5 ng/ml. 131 I-WBS was negative for persistent or recur- rent disease in all patients (i.e. sensitivity = 0%). US identified lymph-node metastases (confirmed at surgery) in 4/6 (67%) patients with stimulated Tg levels . 5 ng/ml, in 2/15 (13%) with Tg . 1 , 5 ng=ml; and in 2/78 (3%) who were Tg-negative. Conclusions: (i) diagnostic 131 I-WBS performed after rhTSH stimulation is useless in the first follow-up of DTC patients; (ii) US may identify lymph node metastases even in patients with low or undetectable serum Tg levels. European Journal of Endocrinology 148 19–24 Introduction Total or near-total thyroidectomy is advocated for patients with papillary or follicular thyroid carcinoma, and is often followed by 131 I-ablation (1–5). However, recurrence rates as high as 20% have been reported in these patients (1, 6, 7), and close follow-up should permit the early detection of persistent or recurrent dis- ease. For years, the ‘standard’ follow-up has been based upon clinical examination, measurement of serum thyroglobulin (Tg) levels, and 131 I whole body scinti- graphy ( 131 I-WBS) (1–4, 8). Until recently, these diag- nostic procedures were performed following thyroid hormone treatment withdrawal, in order to increase serum thyroid-stimulating hormone (TSH) levels above 25 mU/ml (2). However, the resulting hypothy- roidism was poorly tolerated by many patients (9). Recombinant human TSH (rhTSH) recently became available and produces effective thyroid stimulation; its use eliminates the need for thyroid hormone therapy withdrawal and, consequently, hypothyroidism-related side effects are avoided (10–13). Recently, the diagnostic significance of 131 I-WBS obtained following thyroid hormone (T 4 ) withdrawal was questioned because of its poor sensitivity (14), and some investigators have suggested that serum Tg determination alone is the most cost-effective first line in the follow-up of differentiated thyroid cancer (DTC) European Journal of Endocrinology (2003) 148 19–24 ISSN 0804-4643 q 2003 Society of the European Journal of Endocrinology Online version via http://www.eje.org Downloaded from Bioscientifica.com at 06/07/2020 10:00:25PM via Massachusetts Inst of Technology