High Serum Thyroglobulin Research Articles

Hypothyroidism due to biallelic variants in IYD: description of 4 families and a novel variant.

Biallelic loss-of-function variants in the IYD gene cause hypothyroidism resulting from iodine wasting. We describe 8 patients (from 4 families in which the parents are first cousins) who are homozygous for a variant in IYD (including a novel missense deleterious variant, c.791C>T [P264L], in 1 family). Seven patients presented between 5 and 16 years of age with a large goiter, overt hypothyroidism, and a high serum thyroglobulin. The goiter subsided with levothyroxine therapy in most. Upon stopping levothyroxine in 5 patients, goiter and hypothyroidism reappeared in 3. In these 3 patients, a rising serum thyroglobulin concentration preceded hypothyroidism and goiter and urinary iodine excretion was low. In patients who remained euthyroid, urinary iodine was normal. In conclusion, these patients bearing biallelic pathogenic variants in IYD developed a large goiter, a high serum thyroglobulin, and overt hypothyroidism when their iodine intake was low.

PET/CT with <sup>18</sup>F-FDG for TENIS Syndrome in a Patient with Bone Metastasis of Hurthle Cell Thyroid Cancer: a Clinical Case Report

A significant role in improving the prognosis of differentiated thyroid cancer (DTC) in the presence of bone metastases is determined by early diagnosis of metastases, timely and correctly selected treatment tactics for the patient. During dynamic follow-up of patients with DTC after combined treatment (thyroidectomy with radioiodine therapy) are determination of the level of oncomarkers (serum thyroglobulin and antibodies to thyroglobulin) and ultrasound diagnostic of the neck, scanning with radioactive iodine (if clinically indicated). In some cases, patients have TENIS-syndrome (Thyroglobulin Elevated Negative Iodine Scintigraphy, hereinafter TENIS-syndrome), characterized by high serum thyroglobulin level in blood and absence of radioactive iodine accumulation on post therapeutic scintigraphy. According to the research studies, PET/CT with 18F-FDG has high sensitivity and specificity (89 % and 72 %, respectively) in visualization of metastatic radioiodine refractory foci in TENIS-syndrome.This article presents a clinical case of a patient, a 52-year-old woman with Gurtle cell thyroid cancer (pT3aN0M0, stage I) with established TENIS syndrome. Thyroidectomy was performed in September 2019 and radioiodine therapy was performed in January 2022 due to suspected disease progression given high thyroglobulin levels. Given the absence of pathologic accumulation of 131I according to post-therapy radioiodine scanning, PET/CT with 18F-FDG was performed, which revealed a solitary metastasis in the left iliac bone (41×35×42 mm with SUVmax 17.25). In November 2022, radical treatment of the solitary bone metastasis was performed in the scope of resection of the left iliac bone with reconstructive-plastic component. According to the data of control examinations in June 2023, the patient has a complete biochemical and radiologic remission of the disease.

Establishment and validation of a nomogram model for evaluating the metastasis of lymph nodes posterior to the right recurrent laryngeal nerve in papillary thyroid carcinoma

Objective: To explore the related factors of lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) metastasis in papillary thyroid carcinoma (PTC) and establish a nomogram model for evaluating LN-prRLN metastasis. Methods: The clinical data of patients with PTC who underwent surgery in the Department of Thyroid Surgery of the First Affiliated Hospital of Zhengzhou University from January 2020 to December 2021 were retrospectively analyzed. Multivariate logistic regression was used to analyze the related factors of LN-prRLN metastasis and construct a nomogram model for evaluating LN-prRLN metastasis. Meanwhile, the data of 120 patients from January to June 2022 were also collected for external verification. Results: A total of 466 patients with PTC were enrolled, including 106 males and 360 females, and aged 44 (33, 53) years. There were 280 cases in the training group and 186 cases in the internal validation group, respectively. Multivariate logistic regression analysis showed that age (OR=0.966, 95%CI: 0.938-0.996, P=0.027), tumor size (OR=1.048, 95%CI: 1.001-1.098, P=0.043), multifocality (OR=2.459, 95%CI: 1.268-4.767, P=0.008), right central lymph node metastasis reported by ultrasound (OR=3.099, 95%CI: 1.255-7.651, P=0.014), extrathyroid extension (OR=3.561, 95%CI: 1.255-10.102, P=0.017) and serum thyroglobulin level (OR=1.010, 95%CI: 1.001-1.018, P=0.032) were related factors for LN-prRLN metastasis. The area under the curve (AUC) values of receiver operating characteristic (ROC) curves of the training group, internal validation group and external validation group were 0.765 (95%CI: 0.691-0.840), 0.747 (95%CI: 0.657-0.837) and 0.754 (95%CI: 0.639-0.869), respectively. Conclusion: Dissection of the LN-prRLN is recommended for young PTC patients with large tumor size, multifocality, right central lymph node metastasis reported by ultrasound, extrathyroid extension and high serum thyroglobulin level.

Prognostic factors for recurrence in patients with papillary thyroid carcinoma.

The prognostic factors for tumor recurrence and mortality of patients diagnosed with Papillary Thyroid Carcinoma (PTC) with immediate surgery in Colombia has not been reported. To retrospectively evaluate the risk factors for recurrence and survival at 10years in patients with the diagnosis of PTC treated at Fundación Santa Fe deBogota (FSFB). A total of 486 patients with thyroid surgery accompanied by medical follow-up were recruited. Demographic, clinical, and pathological variables were followed-up for a median period of 10years. The most significant variables for recurrence were tumors with > 4cm of size (hazard ratio [HR] = 8.1; 95% confidence interval [CI] = 1.7-55) and extrathyroidal spread (HR = 26.7; 95% CI = 3.1-228). PTC in our population has low rates of mortality (0.6%) and recurrence (9.6%), with an average time of recurrence of 3years. Size of the lesion, positive surgical margins, extrathyroidal spread, and high postoperative serum thyroglobulin (Tg) level act as prognostic factors that determine the likelihood of recurrence. Unlike other studies, the influence of age and gender does not act as a prognostic factor.

Long-term clinical outcomes and prognostic factors for patients with papillary thyroid carcinoma with other organ invasions after adjuvant radioactive iodine.

Papillary thyroid carcinoma (PTC) with other organ invasions is directly related to patient prognosis and quality of life; however, studies on the clinical outcomes of adjuvant radioactive iodine (RAI) for PTC with other organ invasions are limited. This study aimed to clarify the clinical outcomes and prognostic factors for patients with PTC with other organ invasions after adjuvant RAI. Patients with PTC with other organ invasions without distant metastases who underwent surgery and adjuvant RAI were retrospectively reviewed. We evaluated the initial responses based on the American Thyroid Association guidelines and survival rates. Prognostic factors for locoregional recurrence-free survival (LRRFS) were analyzed. Between January 2005 and December 2019, 102 patients were included in the study. Their median age was 55 years. The median follow-up duration was 92 months (range; 30-231 months). The excellent response rate after RAI was 42%. The 7-year overall survival, LRRFS, and recurrence-free survival rates were 100%, 75%, and 75%, respectively. Metastatic lymph node size, resection margin status, and post-RAI suppressed thyroglobulin level were the independent prognostic factors for LRRFS. We demonstrated that 75% of patients with PTC with other organ invasions could achieve long-term survival without recurrence after adjuvant RAI. Future development of effective treatment strategies for large metastatic lymph nodes, gross residual tumors, and high serum thyroglobulin levels is warranted.

Importance of fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in detection of post-thyroidectomy recurrence in differentiated thyroid cancer with negative radio-isotope iodine scan, yet, elevated serum thyroglobulin level

BackgroundThyroid cancer considered the 6th common cancer in female and represents approximately 1% of all cancers. Thyroid cancer is generally characterized by good prognosis, long term survival and low aggressiveness. Its prognosis is related to tumor dimensions, extra capsular extensions, the age at diagnosis and distant metastases sites. Combination between positron emission tomography and computed tomography allow anatomic, functional & molecular information.AimTo demonstrate Fluorine 18 fluorodeoxyglucose positron emission tomography)/computed tomography role for evaluation of post-thyroidectomy recurrence either local or distant metastatic lesions in differentiated cancer thyroid patients with negative radio-isotope iodine scan, yet showing elevated serum thyroglobulin level.ProcedureA prospective study included twenty patients with previous history of differentiated thyroid cancer. All patients after history taking and revising the medical sheet underwent Serum Thyroglobulin level & I-131 whole body scan examinations and then Fluorine 18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography study. The findings of Positron Emission Tomography/Computed Tomography imaging compared with results of histopathology or follow-up clinical results as a gold standard.ResultsFluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography based analysis showed that nineteen true positives and one was true negative as confirmed by the gold standard (Histopathology and clinical follow-up). Thirteen patients had either local recurrence or lymph node metastases without distant metastatic disease, six patients had different distant metastasis. Fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography based analysis showed that nineteen true positives and one was true negative as confirmed by the gold standard (histopathology and clinical follow-up). The accuracy and sensitivity of Fluorine 18 fluorodeoxyglucose positron emission tomography/computed tomography (95%) were significantly better than those of the Computed Tomography alone (84.2% and 80%, respectively).ConclusionsFluorine 18 Fluorodeoxyglucose positron emission tomography/computed tomography provided a critical role in assessment and management of patients with suspected differentiated thyroid recurrence, presenting with high serum thyroglobulin level and negative radio-isotope iodine scan. It enhances diagnostic accuracy through giving exact anatomical localization of recurrent and/or metastatic tumor foci.

Low serum triiodothyronine and potassium levels are associated with increased risk of eclampsia among women in the Eastern Cape Province of South Africa

Background: There is paucity of data on the relationship between thyroid hormones, potassium and eclampsia. Moderate-to-severe iodine deficiency that worsens during pregnancy leads to decreased thyroid hormone output and bioavailability to the brain. Apart from metabolic functions, T3 and T4 are essential fast acting cytosolic and synaptosomal neural transmitters that also regulate neuronal excitatory-inhibitory mechanisms. T3 also regulates the Na + -K + -ATPase pump that maintains the membrane ionic gradient. Hence altered serum potassium, thyroxine and triiodothyronine levels could increase the risk of eclamptic seizures. Methods: Forty-five women with eclampsia, 45 severe preeclampsia and 90 normotensive pregnant controls were enrolled into this study. Levels of thyroid hormones, thyroglobulin and urine iodine concentration (UIC) were measured and compared between the three groups. Results: Eclamptic participants had significantly lower median serum potassium (K), triiodothyronine (FT3), urinary iodine concentration (UIC) but higher serum thyroglobulin (Tg) (K = 3.7 mmol/L; FT3 = 3.8 pmol/L; UIC = 69.5 μg/L; Tg = 39.0 μg/L) than normotensive pregnant controls (K = 4.3 mmol/L; T3 = 4.7 pmol/L; UIC = 169.5 μg/L; Tg = 19.5 μg/L) and participants with severe preeclampsia (K = 4.2 mmol/L; T3 = 4.4 pmol/L; UIC = 95.7 μg/L; Tg = 22.4 μg/L), p < 0.05. Low UIC, low serum T3 and potassium and elevated Tg were independent predictors of eclampsia. Conclusions: Women with iodine deficiency in pregnancy may be at increased risk of eclampsia secondary to the ensuing rapid peripheral turnover of thyroid hormones leading to hypothyroxinaemia and reduced triiodothyronine bioavailability to the central nervous system that can be exacerbated by hypokalaemia.

Preoperatively Predicting the Central Lymph Node Metastasis for Papillary Thyroid Cancer Patients With Hashimoto's Thyroiditis.

BackgroundThe preoperative distinguishment of lymph nodes with reactive hyperplasia or tumor metastasis plays a pivotal role in guiding the surgical extension for papillary thyroid carcinoma (PTC) with Hashimoto’s thyroiditis (HT), especially in terms of the central lymph node (CLN) dissection. We aim to identify the preparative risk factors for CLN metastasis in PTC patients concurrent with HT.Materials and MethodsWe retrospectively reviewed and analyzed the data including the basic information, preoperative sonographic characteristics, and thyroid function of consecutive PTC patients with HT in our medical center between Jan 2019 and Apr 2021. The Chi-square and Fisher’s exact tests were used for comparison of qualitative variables among patients with or without CLN metastasis. Univariate and multivariate logistic regression analyses were used to determine the risk factors for CLN metastasis. The nomogram was constructed and further evaluated by two cohorts produced by 1,000 resampling bootstrap analysis.ResultsA total of 98 in 214 (45.8%) PTC patients were identified with CLN metastasis. In multivariate analysis, four variables including high serum thyroglobulin antibody (TgAb) level (>1,150 IU/ml), lower tumor location, irregular margin of CLN, and micro-calcification in the CLN were determined to be significantly associated with the CLN metastasis in PTC patients with HT. An individualized nomogram was consequently established with a favorable C-index of 0.815 and verified via two internal validation cohorts.ConclusionsOur results indicated that preoperatively sonographic characteristics of the tumor and lymph node condition combined with serum TgAb level can significantly predict the CLN in PTC patients with HT and the novel nomogram may further help surgeons to manage the CLN in this subpopulation.

Role of PET/CT in detection of post-Thyroidectomy recurrence in differentiated cancer thyroid patients with negative radio-isotope iodine scan & elevated serum thyroglobulin level

Abstract Aim of the Work To study of the role of PET/CT in in detection of post-thyroidectomy recurrence in differentiated cancer thyroid patients having negative radio-isotope iodine scan & high serum thyroglobulin level. Materials and Methods The study incorporated 20 patients with previous history of differentiated cancer thyroid. All patients performed Serum Thyroglobulin level Estimation & entire body scan I-131 (WBS) examination & PET/CT study alluded from oncology specialist to Radiology Department. All patients in the study were subjected to history taking &revising the medical sheet. Results PET/CT results will be compared with iodine radio-isotope scan & serum thyroglobulin level and statistical analysis of the collected data will be performed to determine the diagnostic value of the PET/CT in detection of local recurrence or distant metastasis.

A rare association between true thymic hyperplasia and thyroid follicular tumor: a case report

BackgroundTrue thymic hyperplasia is a rare condition characterized by enlargement of the thymus while its normal structure is retained. True thymic hyperplasia is known to accompany Graves’ disease, but no association between true thymic hyperplasia and thyroid follicular tumor has been reported so far. We report a case of true thymic hyperplasia in a patient with a thyroid follicular tumor.Case presentationA 52-year-old Japanese man was referred to our hospital for evaluation of a thyroid mass and a mediastinal mass. His serum thyroglobulin level was high, and hemithyroidectomy was performed to remove the thyroid mass. The resected mass was diagnosed as a follicular tumor of uncertain malignant potential. After resection of the thyroid lesion, the patient’s serum thyroglobulin levels were markedly decreased. Seven months later, the patient underwent resection of the mediastinal mass. On pathological examination, the mass was found to consist of lobules, which formed a corticomedullary structure with Hassall’s bodies, indicating a normal thymic mass with hyperplastic thymic tissue, less organized cellular cords, and intermingled adipose tissue. Immunostaining for cytokeratin 19 and cytokeratin 7 indicated that the lesion was consistent with thymic tissue. The lesion was diagnosed as true thymic hyperplasia, and the histological findings suggested that secondary atrophy had occurred. No evidence of recurrence was observed at 24 months after surgery.ConclusionsWe present a case of a combination of true thymic hyperplasia and thyroidal follicular tumors that, to our knowledge, has not been reported previously. High serum thyroglobulin levels might play a role in hyperplasia of the thymus. Although true thymic hyperplasia is a rare disorder, it should be included in the differential diagnosis of a mediastinal mass in patients with thyroid disease.

An enhanced treatment effect can be expected from a higher serum thyroglobulin level after radioactive iodine therapy

The aim of this study was to investigate if increased serum thyroglobulin (Tg) levels after radioactive iodine (RAI) showed more therapeutic effects in patients with differentiated thyroid cancer (DTC). Data of 65 patients with DTC who underwent RAI from June 2014 to September 2016 were reviewed. Serum thyroglobulin was measured immediately before (Tg1) and 48h (Tg2) after RAI under TSH stimulation. Differences and ratios between serum Tg measurements (DeltaTg = Tg2-Tg1 and RatioTg = Tg2/Tg1) were calculated. The treatment response of distant metastasis was assessed using the RECIST criteria. There was no difference in the median values of Tg1 and Tg2 (2.6 [range, 0.7-1957.5] ng/mL vs. 7.4 [range, 0.7-5276.0] ng/mL, p = 0.240) in all patients (73 scans, 65 patients). In subgroup analysis, Tg levels increased slightly in patients with distant metastasis (8 scans, 7 patients) (Tg1 vs. Tg2; 48.9 [range, 2.4-1957.5] ng/mL vs. 63.2 [range, 4.4-5276.0] ng/mL, p = 0.408). Among patients with distant metastasis, one patient with a partial response to treatment had a more than 4000fold increase in Tg levels and one patient with stable disease showed a 20fold increase in Tg levels. In contrast, five patients with disease progression showed only two to eightfold increase or more than 100fold decrease in Tg levels at 48h after RAI. However, there was a significant increase in serum Tg levels in patients without distant metastasis (65 scans, 58 patients) after RAI (Tg1 vs. Tg2; 2.0 [range, 0.7-141.9] ng/mL vs. 6.8 [range, 0.7-577.7] ng/mL, p = 0.026). A higher elevation of Tg levels after RAI may be associated with a better treatment outcome in DTC patients with distant metastasis. An increase in Tg levels after RAI may reflect the destruction of cancer and thyroid cells.

Risk factors for radioactive iodine-avid metastatic lymph nodes on post I-131 ablation SPECT/CT in low- or intermediate-risk groups of papillary thyroid cancer

ObjectivePost I-131 ablation single-photon emission computed tomography (SPECT)/CT can show radioactive iodine (RAI)-avid cervical metastatic lymph nodes (mLN) in differentiated thyroid cancer. This study aimed to evaluate the incidence of RAI-avid mLN on post I-131 ablation SPECT/CT and the risk factors related to metastasis among patients with papillary thyroid cancer (PTC) in the low- or intermediate-risk groups.Study design and settingAmong 339 patients with PTC who underwent total thyroidectomy followed by I-131 ablation, 292 (228 women, 64 men) belonging to the low- or intermediate-risk groups before I-131 ablation, and with sufficient clinical follow-up data were enrolled. The risk groups were classified based on the American Thyroid Association 2015 guideline. Each patient was followed-up for at least 24 months after the ablation (median: 30 months). The clinical, pathologic, and biochemical factors of PTC were reviewed, and their relationships to RAI-avid mLN on SPECT/CT were analyzed.ResultsOf the 292 patients, 61 and 231 belonged to the low-and intermediate-risk groups, respectively. Four (6.5%) patients in the low-risk group and 31 (13.0%) patients in the intermediate-risk group had RAI-avid mLN. A high preablation TSH-stimulated serum thyroglobulin (Tg) level in the low- or intermediate-risk group predicted the presence of RAI-avid mLN (cut-off = 0.5; hazard ratio (HR): 2.96; p = 0.04). In the subgroup analysis by risk group, TSH-stimulated serum Tg only predicted RAI-avid mLN in the low-risk group (cut-off = 1.0; HR: 5.3; p = 0.03).ConclusionThe incidence of RAI-avid mLN on postablation SPECT/CT was relatively high in both low- and intermediate-risk patients with PTC, and high preablation TSH-stimulated serum Tg level was a predictor of metastasis, especially in the low-risk group. A selective treatment approach should be considered in patients with high preablation TSH-stimulated serum Tg level.

Clinico-social factors to choose radioactive iodine dose in differentiated thyroid cancer patients: an Asian survey.

This survey was designed to investigate the practice of radioactive iodine (RAI) therapy and clinico-social factors related to RAI dose in differentiated thyroid cancer (DTC) patients among Asian countries. A survey questionnaire was mailed to Asian Nuclear Medicine physicians that addressed the infrastructure, general regulations on RAI therapy, adherence to recommendations, RAI dose selection, factors to elevate RAI dose, and follow-up protocols in DTC patients. Contrived RAI practice recommendations were based on key international guidelines. A total of 38 institutes from 20 Asian countries were enrolled. Dose administration criterion was 30 mCi, but release criterion was variable (5-70 μSv/h). When the administered RAI dose was classified according to three risk stratifications, RAI dose distribution was variable, especially in the low-risk group. In this group, 14.0% of respondents preferred no ablation, 54.5% were treated with 0-30 mCi, 21.5% were treated with 30-50 mCi, and 10.0% were administered even higher doses of 80-100 mCi. The major factors that influenced the elevated RAI doses in the respondents included high serum thyroglobulin (Tg), inadequate information on lymph node involvement, and histopathology reporting. Although serum Tg measurement is included in most of the institutes as a follow-up tool, neck ultrasound was omitted in 25% and in another 25% a whole-body scan was not included. Different RAI dose ranges are used in the low-risk group probably because the enrolled physicians consider RAI dose elevation on the basis of clinico-social factors beyond pre-existed guidelines. Our study may enable closer harmonization of RAI therapy practice in Asian countries.

Clinical Value of 99mTc-3PRGD2 SPECT/CT in Differentiated Thyroid Carcinoma with Negative 131I Whole-Body Scan and Elevated Thyroglobulin Level

The aim of this study was to assess the usefulness of integrin imaging with 99mTc-PEG4-E[PEG4-c(RGDfK)]2 (99mTc-3PRGD2) single photon emission computed tomography (SPECT)/computed tomography (CT) in detecting recurrent disease in patients with differentiated thyroid cancer (DTC), negative radioiodine whole-body scan (WBS) and high serum thyroglobulin (Tg). Thirty-seven patients who underwent total thyroidectomy followed by radioactive iodine ablation and had negative radioiodine WBS but elevated Tg levels were included. 99mTc-3PRGD2 SPECT/CT was performed 1 week after the negative diagnostic 131I WBS. Diagnostic performance indicators, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), for 99mTc-3PRGD2 SPECT/CT was calculated. The correlations between SPECT/CT results and clinic-pathological characteristics were examined. In 30 (81.1%) of the 37 patients, 99mTc-3PRGD2 SPECT/CT showed positive uptake. The sensitivity, specificity, PPV, and NPV of SPECT/CT to detect recurrent disease at follow-up were 96.6%, 75%, 93.3% and 85.7%, respectively. The sensitivity and PPV of SPECT/CT increased with increasing serum Tg levels. 99mTc-3PRGD2 SPECT/CT showed high sensitivity and PPV in the detection of recurrence among DTC patients with higher Tg levels and negative WBS, and the probability of obtaining a positive SPECT/CT result was related with the level of Tg.

Use of thyroglobulin as a tumour marker.

It is worthwhile to measure serum thyroglobulin (TG) level in thyroid cancer before subjecting patients to surgery for two reasons. Firstly, if the level is high, it may give a clue to the local and metastatic tumour burden at presentation; secondly, if the level is normal, it identifies the patients who are unlikely to show rising TG levels in the presence of thyroid cancer. Those who have high serum TG before surgery will show up recurrence as rising serum TG during the postoperative period. Those who do not have high serum TG before surgery will not show up rising serum TG in the presence of recurrent disease. In the latter situation, normal TG level gives only a false reassurance regarding recurrence of disease. Nevertheless, rising serum TG during the postoperative period must be interpreted cautiously because this could be due to the enlargement of non-cancerous residual thyroid tissue inadvertently left behind during surgery.

Analysis of predictability of F-18 fluorodeoxyglucose-PET/CT in the recurrence of papillary thyroid carcinoma.

Whether preoperative F‐18 fluorodeoxyglucose (FDG)‐positron emission tomography/computed tomography (PET/CT) can predict recurrence of papillary thyroid carcinoma (PTC) remains unclear. Herein, we evaluated the potential of primary tumor FDG avidity for the prediction of tumor recurrence in PTC patients. A total of 412 PTC patients (72 males, 340 females; age: 47.2 ± 12.2 years; range: 17–84 years) who underwent FDG‐PET/CT prior to total thyroidectomy (n = 350), subtotal thyroidectomy (n = 2), or lobectomy (n = 60) from 2007 to 2011 were analyzed. The predictive ability for recurrence was investigated among various clinicopathological factors, BRAFV 600E mutation, and preoperative FDG avidity of the primary tumor using Kaplan–Meier (univariate) and Cox proportional hazards regression (multivariate) analyses. Of the 412 patients, 19 (4.6%) experienced recurrence, which was confirmed either by pathology (n = 17) or high serum thyroglobulin level (n = 2), during a mean follow‐up period of 43.9 ± 16.6 months. Of the 412 patients, 237 (57.5%) had FDG‐avid tumors (maximum standardized uptake value, 7.1 ± 7.0; range: 1.6–50.5). Kaplan–Meier analysis revealed that tumor size (P = 0.0054), FDG avidity of the tumor (P = 0.0049), extrathyroidal extension (P = 0.0212), and lymph node (LN) stage (P < 0.0001) were significant predictors for recurrence. However, only LN stage remained a significant predictor in the multivariate analysis (P < 0.0001). Patients with FDG‐avid tumors had higher LN stage (P < 0.0001), larger tumor size (P < 0.0001), and more frequent extrathyroidal extension (P < 0.0001). In conclusion, FDG avidity of the primary tumor in preoperative FDG‐PET/CT could not predict the recurrence of PTC. LN stage was the only identified predictor of PTC recurrence.

Value of Dedicated Head and Neck 18F-FDG PET/CT Protocol in Detecting Recurrent and Metastatic Lesions in Post-surgical Differentiated Thyroid Carcinoma Patients with High Serum Thyroglobulin Level and Negative 131I Whole-body Scan.

Objective(s):In clinical practice, approximately 10-25% of post-surgical differentiated thyroid carcinoma (DTC) patients with high serum thyroglobulin (Tg) and negative 131I whole-body scan (WBS) have poor prognosis due to recurrent or metastatic lesions after radioactive iodine treatment. The purpose of this study was to evaluate the value of 18F-FDG PET/CT scan in DTC patients with high serum Tg level and negative 131I WBS.Methods:69 post-surgical DTC patients with high serum Tg level and negative post ablation 131I WBS were enrolled in this study. All DTC patients underwent head and neck ultrasound, CT scan and whole-body 18F-FDG PET/CT, based on the dedicated head and neck protocol.Results:Overall, 92 lesions were detected in 43 (62.3%) out of 69 patients with positive 18F-FDG PET/CT scan, compared to only 39 lesions detected on CT scan in 26 (37.7%) out of 69 patients. The sensitivity, accuracy and negative predictive value of 18F-FDG PET/CT were 88%, 87% % and 76%, respectively, which were significantly higher than those of CT scan (67.2%, 54.3% and 48.8%, respectively) (P<0.01). Specificity and positive predictive value of 18F-FDG PET/CT (90.5% and 95.2%, respectively) were similar to those of CT scan (95.2% and 96.2%, respectively) (P>0.05). The maximum standardized uptake value (SUVmax) threshold was 4.5 with a good diagnostic value (sensitivity of 92.3% and specificity of 100%). The dedicated head and neck 18F-FDG PET/CT protocol altered the treatment plan in 33 (47.8%) out of 69 DTC patients with high serum Tg level and negative 131I WBS.Conclusion:Dedicated head and neck 18F-FDG PET/CT protocol showed a higher diagnostic value, compared to CT scan and played an important role in detecting recurrent or metastatic lesions in post-surgical DTC patients with high serum Tg level and negative 131I WBS.

Stimulated high serum thyroglobulin with negative whole body imaging do not warrant an aggressive diagnostic and therapeutic approach in differentiated thyroid cancer patients: A follow-up of 5 years or till recurrence.

To study the clinical significance of stimulated high serum thyroglobulin (sTg) and of normal whole body imaging (WBI) in differentiated thyroid cancer (DTC) patients during their first follow-up and in a 5 years follow-up or till recurrence. Sixty four DTC patients were retrospectively studied and were divided into two groups. Group 1, of 35 patients with disease free status on their first follow-up and group 2, of 29 patients with high sTg (>2 μg/mL), but with normal WBI, iodine-131 (¹³¹I) findings. Patients were categorized into low, intermediate and high risk patients based on the ¹³¹I WBS findings. Histology, stage and risk-categories of both groups were statistically correlated. Best sTg cut-off for predicting recurrence was generated by receiver operating characteristic (ROC). Odd ratio for sTg trend was also analyzed for risk of recurrence in group 2. Independent t test was used for progression free survival (PFS) comparison of the two groups. No statistical differences were seen in histology, stage and risk category distributions between the groups. Group 2 patients with high sTg (range 2.5-81 μg/L, mean 20.5 μg/L) on their first follow-up had higher risk of recurrence (odd ratio 4.304) but P value was insignificant (P:0.090). Eighty six per cent of group 2 patients showed decreasing trends and in 62% of group 2 patients, high serum sTg fell to normal. Indeed, decreasing trends of sTg reduced the risk of recurrence (odd ratio 1.3939, P:0.79). Analysis by ROC showed that sTg>11 μg/L was the best cut-off in predicting recurrence with sensitivity 100% and specificity 56%. High sTg was not associated with low PFS, (P:0.232), however patients with increasing sTg had significantly shorter PFS (P<0.005). High sTg with negative ¹³¹I WBS did not warrant an aggressive DTC disease. These patients in their 5 years or till recurrence follow-up showed downward trends of serum sTg, no higher risk or recurrence and no shorter PFS.

Clinical applications of SPECT/CT after first I‐131 ablation in patients with differentiated thyroid cancer

This study aimed to determine which thyroid cancer patients would benefit from SPECT/CT in addition to whole-body planar scintigraphy (RxWBS) for the detection and characterization of I-131 focal uptake after first ablation. Neck and thoracic SPECT/CT was performed in 187 patients with I-131 focal uptake suggestive of remnant thyroid tissue (Rem group, n = 152) or presumed lymph node (LN) metastases (mLN group, n = 35) on RxWBS. Clinical and pathologic parameters were analysed and compared in patients with and without additional SPECT/CT findings. wIn the Rem group, SPECT/CT revealed additional occult findings on RxWBS in 13 patients (8·6%). The serum thyroglobulin levels at the time of ablation were significantly higher in patients with additional SPECT/CT findings than in patients without additional findings (4·3 ± 3·4 ng/ml vs 1·6 ± 2·7 ng/ml, P = 0·001). In the mLN group, SPECT/CT demonstrated only remnant thyroid tissues without evidence of lymph node metastasis in 14 (40·0%) patients, whereas in the remaining 21 (60·0%) patients, I-131 uptake was confirmed in the corresponding neck and mediastinal lymph nodes on SPECT/CT. Even in the Rem group, additional SPECT/CT could provide useful information for detecting hidden metastasis, especially in patients with high serum thyroglobulin levels. SPECT/CT should be recommended for patients with focal uptake lymph node metastasis on RxWBS.

Value of SPECT/CT in Cervical Vertebra Metastasis Mimicking Residual Thyroid Tissue on Planar I-131 Scan

A total thyroidectomy was performed on a 62 year-old male patient with 3.5 cm cold nodule and diagnosis of differentiated thyroid carcinoma was made. He received 200 mCi of I-131 because pulmonary metastases were founded on computed tomography and his serum thyroglobulin level was high (>300 ng/ml). Post-therapy planar whole body scan showed diffuse pulmonary tracer accumulation consistent with pulmonary metastases, 3 foci of activities in the thyroid region of neck and physiological tracer uptake in the liver. Initially, it was considered that high serum thyroglobulin level was caused by pulmonary metastases and activities in the neck were due to residual thyroid tissue. But, single photon emission computed tomography/computed tomography (SPECT/CT) images demonstrated that the activity in the midline of the neck was originated in the cervical (C5-6) vertebra due to bone metastasis. Cervical vertebra metastasis in the same level with probable residual thyroid tissue in planar I-131 whole body scan can be easily overlooked. We considered that the complementary SPECT/CT for head and neck region should be used not only in the selected differentiated thyroid patients with unexpected abnormal activity but also in patients with expected residual thyroid tissue, salivary gland or mouth activity in planar I-131 whole body scan.