Diagnostic Value of a Single Serum Thyroglobulin Determination on and Off Thyroid Suppressive Therapy in the Follow‐up of Patients With Differentiated Thyroid Cancer

Abstract

To assess the significance of a single serum thyroglobulin (Tg) determination on and off thyroid suppressive therapy, serum Tg measurements have been performed in 349 serum samples from 82 patients with differentiated thyroid cancer. All samples were collected after total thyroidectomy with or without subsequent ablation of residual thyroid tissue by radioiodine. One hundred and fifty-three samples were obtained while the patients were on thyroid suppressive therapy and 196 after withdrawal of medication. The results of serum Tg assays were analysed in relation to the presence or absence of residual or metastatic thyroid tissue, as assessed by clinical and laboratory evaluation, including 131I whole body scan. In patients with thyroid residue but no metastases, undetectable serum Tg (false negative results) occurred in 45% of cases off therapy and in 92.9% of cases during therapy. In the presence of metastases no undetectable serum Tg result was found in patients off therapy, while four (6.9%) out of 58 samples from patients with bone and/or lung metastases and seven (31.8%) out of 22 samples from patients with lymph node metastases alone were undetectable (falsely negative) during suppressive therapy. Serum Tg was undetectable in sera from patients with no evidence of thyroid residue or metastatic disease in all but one (1.7%) of 59 samples on and three (5.4%) of 56 samples off suppressive therapy. These Tg results were confirmed to be truly rather than falsely positive, since evidence of metastatic disease was obtained by whole body scan after the administration of therapeutic doses of 131I.(ABSTRACT TRUNCATED AT 250 WORDS)

Management of papillary and follicular (differentiated) thyroid cancer: new paradigms using recombinant human thyrotropin.

“…Thyroglobulin concentrations during THST should be undetectable or low ( < 1 µg/l) in patients who are free of disease, but are more accurate when serum TSH concentrations are increased (Pacini et al 1985, Haugen et al 1999. In patients with undetectable Tg concentrations during THST who have no clinically apparent residual cancer, measurement of an rhTSH-stimulated Tg concentration distinguishes those who are truly disease-free from those with tumor who require further diagnostic testing, therapeutic procedures, or both (Pacini et al 2001c, Haugen et al 2002, Mazzaferri & Kloos 2002.…”

“…Nevertheless, the Tg may remain high for a year or more after 131 I treatment before spontaneously becoming undetectable (Cailleux et al 2000, Pacini et al 2001a. During long-term follow-up, Tg should be measured after levothyroxine withdrawal or rhTSH administration, which lowers the false-negative rate well below that of DxWBS (Pacini et al 1985, Haugen et al 1999, Cailleux et al 2000.…”

Evaluation of circulating thyroid‐specific transcripts as markers of thyroid cancer relapse

“…Our data are in agreement with reports from the literature, reporting undetectable or low serum TG levels in 20 -80% of patients with persistent or metastatic disease. [23][24][25][26] Stimulation with rhTSH has been demonstrated to increase the sensitivity of serum TG testing carried out during THST. 20,26 In our experience, using a cut-off level of Ͼ1 g/l, rhTSH-stimulated serum TG predicted the presence of tumor relapse in 93.3% of patients.…”

Diagnóstico de metástases de carcinoma papilífero de tiróide através da dosagem de tiroglobulina no líquido obtido da lavagem da agulha utilizada na punção aspirativa

“…Posteriormente, o seguimento inclui palpação da região cervical, ultra-sonografia cervical (USC), pesquisa de corpo inteiro com 1 3 1 I (PCI) e dosagens de tiroglobulina sérica (sTg) durante terapia com Levo-tiroxina (L-T4) e pós-estímulo com TSH (recombinante ou em hipotiroidismo) (1)(2)(3)(4)(5)(6). Portanto, o objetivo do seguimento do paciente com CDT é a detecção precoce e o tratamento de metástases ou de doença recorrente.…”