Optimal Threshold of Stimulated Serum Thyroglobulin Level for 18F-FDG PET/CT imaging in Patients with Thyroid Cancer / 华中科技大学学报（医学）（英德文版）

This study was to explore the optimal threshold of thyroid-stimulating hormone (TSH)-stimulated serum thyroglobulin (s-Tg) for patients who were to receive 18F-fluorodeoxyglucose (18F-FDG) PET/CT scan owing to clinical suspicion of differentiated thyroid cancer (DTC) recurrence but negative post-therapeutic 131I whole-body scan (131I-WBS).A total of 60 qualified patients underwent PET/CT scanning from October 2010 to July 2014.The receiver operating characteristic (ROC) curve analyses showed that s-Tg levels over 49 μg/L led to the highest diagnostic accuracy of PET/CT to detect recurrence,with a sensitivity of 89.5％ and a specificity of 90.9％.Besides,bivariate correlation analysis showed positive correlation between s-Tg levels and the maximum standardized uptake values (SUVmax) of 18F-FDG in patients with positive PET/CT scanning,suggesting a significant influence of TSH both on Tg release and uptake of 18F-FDG.So,positive PET/CT imaging is expected when patients have negative 131I-WBS but s-Tg levels over 49 μg/L.

Diagnostic Value of Preoperative Serum Thyroglobulin Measurement for the Diagnosis of Malignancy in Follicular or Hurthle Cell Neoplasms of the Thyroid Gland / 고신대학교의과대학학술지

OBJECTIVES: The aim of this retrospective study was whether serum Tg predicts malignancy in follicular or Hurthle-cell neoplasms on fine needle aspiration. METHODS: A chart review of 111 patients (90 females, 21 males; mean age 46.8 +/- 11.9 years) with follicular or Hurthle-cell neoplasms on fine needle aspiration, who were surgically treated between Sep. 2001 and Sep. 2011, was performed. Predictive factors for malignancy were identified by the chi-squared test and multivariate logistic regression. RESULTS: There were no differences between 41 malignant and 70 benign lesions in serum Tg or any of the normalized indexes. Receiver-operator characteristic analysis revealed no cut-off value. Lesions with serum Tg levels greater than 500 g/L had no significant difference. And also there were no independent predictors of malignancy by multivariate logistic regression. CONCLUSIONS: In this study, the author found that serum Tg has poor accuracy for predicting malignancy in follicular or Hurthle cell neoplasms on fine needle aspiration.

Serum Thyroglobulin Varies according to Thyrotropin Levels during Preparation for Treatment by Radioactive Iodine Ablation and Scan / 대한내분비외과학회지

PURPOSE: Periods of L-T4 withdrawal and low iodine diet, which are required prior to the treatment and tracking tests that take place after a thyroidectomy, can be of a long duration and cause suffering for patients. The purpose of this study, conducted in South Korea, was to confirm if periods of L-T4 withdrawal and low iodine diet can be shortened by using TSH level prediction. By inquiring into the correlation between TSH level and serum Tg level, and measurement of the amount of iodine present in urine during the low iodine diet period, a thyroglobulin (Tg) cutoff level can be predicted. METHODS: total of 168 patients were included as research subjects. In each case, L-T4 was suspended 3-4 weeks prior to conducting radioactive iodine ablation and 131I scan, and then a low iodine diet was carried out for 2-4 weeks. Serum TSH, Tg and anti-Tg antibodies were measured on the second week of L-T4 withdrawal, and the spot urine Iodine/Creatinine ratio was measured on the second and fourth week after treatment. RESULTS: Three weeks after L-T4 withdrawal, TSH levels increased to over 30μIU/ml in 97.2% of the patients, and serum thyroglobulin levels also increased with TSH level to over 30μIU/ml. There was no measured difference in the amount of iodine in the subject's urine during the low iodine diet period. CONCLUSION: It was found that L-T4 withdrawal can be reduced to 3 weeks or less, and that the Tg cutoff level differs according to TSH level. Based on these results, we suggested that the low iodine diet period can be reduced to 1-2 weeks.

Diagnostic Significance of Serum Thyroglobulin Measurement in the Follow - up of Patients with differentiated Thyroid Cancer / 대한내분비학회지

BACKGROUND: Although serum thyroglobulin (Tg) has been proved to be a good tumor marker in the follow-up of the well differentiated thyroid cancer, some patients show low detectable Tg with negative 131I scan. In the present study, we tried to determine the lowest level of serum Tg which suggests requirement of aggressive work-up for the recurrent or metastatic thyroid cancer. METHODS: Serum Tg levels were measured in 102 patients with well differentiated thyroid cancer who had underwent thyroidectomy followed by 131I ablative therapy. Of 102 patients, 44 patients had no remnant thyroid tissue, while 58 patients had remnant thyroid. Serum Tg levels were measured while TSH-suppressive dose of T4 was administered (on T4 therapy) and then T4 was discontinued for 4 weeks to increase serum TSH level (off T4 therapy), then serum Tg levels were analyzed in relation to the presence or absence of recurrent or metastatic thyroid cancer, assessed by I scan and operation with reference to the physical examination, chest X-ray and thyroid ultrasonogram. RESULTS: Of 102 patients, 16 patients were found to have recurrent or matastatic thyroid cancer. Among them, 10 patients didnt have any remnant thyroid, while 6 patients had remnant thyroid. Serum Tg was undetectable on T4 therapy in 6 patients, but rose higher than 30 ng/mL off T4 therapy in 2 patients, while Tg remained undetectable in other 4 patients. In all 10 patients whoseTg levels were higher than 1 ng/mL. on T4 therapy, Tg rose higher than 30 ng/mL off T4 therapy. The best cut-off value of serum Tg which suggests recurrent or metastatic disease in patients without remnant thyroid was 3 ng/mL on T therapy (sensitivity 60%, specificity 91%, accuracy 84%) and 30 ng/mL off T4 therapy (sensitivity 80%, specificity 75%, accuracy 77%). In patients with remnant thyroid, cut-off value of serum Tg could not be determined because of the low sensitivity and specificity. CONCLUSION: In patients with well differentiated thyroid cancer who have no remnant thyroid, serum Tg level lower than 3 ng/mL on T4 therapy can warrant following-up of patients only with such clinical measures only such as physical examination and thyroid ultrasonogram. However, patients with Tg level of 3 ng/mL or more requires Tg measurements off T4 therapy and 131I scan to evaluate the possibility of recurrent or metastatic thyroid cancer.

Serum Thyroglobulin Concentrations in Congenital Hypothyroidism

PURPOSE: To investigate the serum levels of thyroglobulin in 35 Children with proven congenital hypothyroidism and the value of serum thyroglobulin (Tg) determination in the differential diagnosis of congenital hypothyroidism. METHODS: Thirty five patients diagnosed with congenital hypothyroidism by clinical symptoms, physical findings, thyroid function tests and radionuclide thyroid scan were available for study. The age of subjects was ranged between 2 weeks and 8.1 years. Serum thyroglobulin was measured by immunoradiometric assay (Thyroglobulin IRMA Pasteur kit). The control groups consisted of 10 normal children with similar age. RESULTS: 1) The male to female ratio was about 1 : 1.7. 2) In etiologic classification, thyroid dysgenesis was 29 cases (82.9%) and dyshormonogenesis was 6 cases (17.1%). Among the thyroid dysgenesis, athyreosis was 18 cases (51.5%), ectopic gland was 6 cases (17.1%), and hypoplastic gland was 5 cases (14.3%). 3) Serum thyroglobulin concentration of athyreosis (5.6+/-6.4ng/mL) was the lowest in children with congenital hypothyroidism, and serum thyroglobulin concentrations of both athyreosis and hypoplastic thyroid gland (11.6+/-6.5ng/mL) were significantly lower than the concentration of normal children (25.6+/-11.1ng/mL). 4) Serum thyroglobulin concentration in children with ectopic gland (22.7+/- 11.3ng/mL) and dyshormonogenesis (31.6+/-20.5ng/mL) was same as the concentration of normal children. CONCLUSIONS: Serum thyroglobulin measurement may be useful in the differetial diagnosis of athyreosis from other etiologies of congenital hypothyroidism.

Serum Thyroglobulin Concentrations in Congenital Hypothyroidism

PURPOSE: To investigate the serum levels of thyroglobulin in 35 Children with proven congenital hypothyroidism and the value of serum thyroglobulin (Tg) determination in the differential diagnosis of congenital hypothyroidism. METHODS: Thirty five patients diagnosed with congenital hypothyroidism by clinical symptoms, physical findings, thyroid function tests and radionuclide thyroid scan were available for study. The age of subjects was ranged between 2 weeks and 8.1 years. Serum thyroglobulin was measured by immunoradiometric assay (Thyroglobulin IRMA Pasteur kit). The control groups consisted of 10 normal children with similar age. RESULTS: 1) The male to female ratio was about 1 : 1.7. 2) In etiologic classification, thyroid dysgenesis was 29 cases (82.9%) and dyshormonogenesis was 6 cases (17.1%). Among the thyroid dysgenesis, athyreosis was 18 cases (51.5%), ectopic gland was 6 cases (17.1%), and hypoplastic gland was 5 cases (14.3%). 3) Serum thyroglobulin concentration of athyreosis (5.6+/-6.4ng/mL) was the lowest in children with congenital hypothyroidism, and serum thyroglobulin concentrations of both athyreosis and hypoplastic thyroid gland (11.6+/-6.5ng/mL) were significantly lower than the concentration of normal children (25.6+/-11.1ng/mL). 4) Serum thyroglobulin concentration in children with ectopic gland (22.7+/- 11.3ng/mL) and dyshormonogenesis (31.6+/-20.5ng/mL) was same as the concentration of normal children. CONCLUSIONS: Serum thyroglobulin measurement may be useful in the differetial diagnosis of athyreosis from other etiologies of congenital hypothyroidism.