Do Thyroid Cancer Patients with Basal Undetectable Tg Measured by Current Immunoassays Require rhTSH Testing?

Abstract

Objective: To evaluate the predictive value of disease free status of basal thyroglobulin (Tg) in differentiated thyroid carcinoma (DTC).

Design: Basal and recombinant human TSH (rhTSH) stimulated Tg measured with a commercial immunoassay (Liaison DiaSorin, Italial), neck ultrasonography (US) and fine needle aspiration cytology if required were performed in DTC patients followed prospectively for 6.8 years in a university hospital. 92 consecutive DTC patients were included. 74 patients with basal and stimulated Tg <1.0 ng/ml and Tg antibodies and US negative were considered as disease-free and persistent/recurrent disease was detected in 18 patients. In 25/74 disease-free patients rhTSH test was repeated within one year.

Results: 63/92 patients had undetectable basal Tg (<0.5 ng/ml), with rhTSH-Tg <0.5 ng/ml in 52, in 6 rhTSH-Tg between 0.5 and 1 ng/ml, in 2 between 1–2 ng/ml (disease-free after 3 years of follow-up) and >2.0 ng/ml (mean 4.1±2.4 ng/ml) in another 3, with US lymphatic metastasis confirmed histologically. Disease-free state was predicted with a sensitivity (S) of 66.7% and specificity (Sp) of 75.7% for basal Tg-0.5 ng/ml, and S 100% and Sp 85.1% for stimulated Tg-0.92. rhTSH test and US were repeated within one year in 25 disease-free patients with Tg<1.0 ng/ml. No further elevation below 1 ng/ml was observed.

Conclusions: Low risk patients with undetectable basal Tg measured with current commercially available immunoassays should be followed with at least one rhTSH stimulated Tg and neck US because of the insufficient predictive value for recurrence/persistent disease of basal Tg.

Key words

thyroid cancer - thyroglobulin - thyroid ultrasound

References

• 1 Jemal A, Siegel R, Ward E et al. Cancer statistics, 2006.  CA Cancer J Clin. 2006;  56 106-130
• 2 Hay ID, Grant CS, van Heerden JA et al. Papillary thyroid microcarcinoma: a study of 535 cases observed in a 50-year period.  Surgery. 1992;  112 1139-1146 discusión, 1146–1147
• 3 Pacini F, Schlumberger M, Dralle H et al. European Thyroid Cancer Taskforce European consensus for the management of patients with differentiated thyroid carcinoma of the follicular epithelium.  Eur J Endocrinol. 2006;  154 787-803
• 4 Cooper DS, Doherty GM, Haugen BR et al. American Thyroid Association (ATA) Guidelines Taskforce on Thyroid Nodules and Differentiated Thyroid Cancer. Revised American Thyroid Association management guidelines for patients with thyroid nodules and differentiated thyroid cancer.  Thyroid. 2009 Nov;  19 (11) 1167-1214
• 5 Castagna MG, Brilli L, Pilli T et al. Limited value of repeat recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin testing in differentiated thyroid carcinoma patients with previous negative rhTSH-stimulated thyroglobulin and undetectable basal serum thyroglobulin levels.  J Clin Endocrinol Metab. 2008;  93 76-81
• 6 Giovanella L, Maffioli M, Ceriani L et al. Unstimulated high sensitive thyroglobulin measurement predicts outcome of differentiated thyroid carcinoma.  Clin Chem Lab Med. 2009;  10 [Epub ahead of print]
• 7 Smallridge RC, Meek SE, Morgan MA et al. Monitoring thyroglobulin in a sensitive inmmunoassay has comparable sensitivity to recombinant human TSH-stimulated thyroglobulin in follow-up of thyroid cancer patients.  J Clin Endocrinol Metab. 2007;  92 82-87
• 8 Baudin E, Do Cao C, Cailleux AF et al. Positive predictive value of serum thyroglobulin levels, measured during the first year of follow-up after thyroid hormone withdrawal, in thyroid cancer patients.  J Clin Endocrinol Metab. 2003 Mar;  88 (3) 1107-1111
• 9 Cailleux AF, Baudin E, Travagli JP et al. Is diagnostic iodine-131 scanning useful after total thyroid ablation for differentiated thyroid cancer?.  J Clin Endocrinol Metab. 2000;  85 175-178
• 10 Pacini F, Capezzone M, Elisei R et al. Diagnostic 131-iodine whole body scan may be avoided in thyroid cancer patients who have undetectable stimulated serum Tg levels after initial treatment.  J Clin Endocrinol Metab. 2002;  87 1499-1501
• 11 Baudin E, Do Cao C, Cailleux AF et al. Positive predictive value of serum thyroglobulin levels, measured during the first year of follow-up after thyroid hormone withdrawal, in thyroid cancer patients.  J Clin Endocrinol Metab. 2003;  88 1107-1111
• 12 Robbins RJ, Tuttle RM, Sharif RN et al. Preparation by recombinant human thyrotropin or thyroid hormone withdrawal are comparable for the detection of residual differentiated thyroid carcinoma.  J Clin Endocrinol Metab. 2001;  86 619-625
• 13 Pacini F, Molinaro E, Lippi F et al. Prediction of disease status by recombinant human TSH_stimulated serum Tg in the postsurgical follow-up of differentiated thyroid carcinoma.  J Clin Endocrinol Metab. 2001;  86 5686-5690
• 14 Kloos RT, Mazzaferri EL. A single recombinant human thyrotropin-stimulated serum thyroglobulin measurement predicts differentiated thyroid carcinoma metastases three to five years later.  J Clin Endocrinol Metab. 2005;  90 5047-5057
• 15 Fumarola A, D’Alessandri M, Dicorato P et al. Diagnostic Accuracy of rhTSH Test with Neck Ultrasonography in Differentiated Thyroid Cancer Follow-up.  Exp Clin Endocrinol Diabetes. 2010;  [Epub ahead of print]
• 16 Giovanella L. Highly sensitive thyroglobulin measurements in differentiated thyroid carcinoma management.  Clin Chem Lab Med. 2008;  46 1067-1073
• 17 Spencer CA, Lopresti JS. Measuring thyroglobulin and thyroglobulin autoantibody in patients with differentiated thyroid cancer.  Nat Clin Pract Endocrinol Metab. 2008;  4 223-233

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