Papillary and follicular thyroid carcinoma

Long-Term Outcomes After Hepatic and Pancreatic Resections for Metastases from Thyroid Cancer: a Systematic Review of the Literature

PURPOSE

The objective of our systematic review was to evaluate the long-term outcomes of surgical resection as a treatment strategy for liver and pancreatic metastases from thyroid cancer (TC).

METHODS

A systematic search of three electronic databases for articles published up to October 2018 was conducted. All appropriate observational studies and case reports which reported outcomes from patients with TC metastatic to the liver or pancreas were considered eligible for inclusion in the present systematic review.

RESULTS

A total of 15 studies, which comprised of 16 patients that underwent hepatic or pancreatic resection for TC metastasis, were included in the present systematic review; among them, 5 presented with metastasis to the liver, whereas 11 had pancreatic metastatic disease. The median time interval between the initial thyroidectomy and the diagnosis of metastases (either hepatic or pancreatic) was 60 months (SE 23.8, 95% CI 13.3-106.7) for the entire cohort and the mean overall survival was 37.6 months (SE 8, 95% CI 22-53.3). Five patients with pancreatic metastases presented with recurrence whereas no recurrences were noted in patients with liver metastases.

CONCLUSIONS

Surgical resection of liver and pancreatic metastases from TC seems to be a safe and efficient treatment option for selected patients. In that setting, long-term outcomes in patients with resected TCLM are encouraging given the absence of recurrence as reported from the included studies, whereas in the case of TCPM, survival is limited due to advanced disease at diagnosis and recurrence rates.

Circulating ctDNA methylation quantification of two DNA methyl transferases in papillary thyroid carcinoma

Papillary thyroid cancer (PTC) is the most common type of cancer among thyroid malignancies. Tumor-related methylation of circulating tumor DNA (ctDNA) in plasma could represent tumor specific alterations can be considered as good biomarkers in circulating tumor cells. In this study, we studied the methylation status of seven promoter regions of two DNA methyl Transferases (MGMT and DNMT1) genes as the methylated ctDNA in plasma and tissue samples of patients with PTC and goiter patients as noncancerous controls.

METHODS

Both ctDNA and tissue genomic DNA of 57 PTC and 45 Goiter samples were isolated. After bisulfite modification, the methylation status was studied by Methylation-Sensitive High Resolution Melting (MS-HRM) assay technique. Four promoter regions of O6-methylguanine-DNA methyltransferase (MGMT) and three promoter regions of DNA methyltransferase 1 (DNMT1) were assessed.

RESULTS

From seven candidate promoter regions of two methyltrasferase coding genes, the methylation status of ctDNA within MGMT (a), MGMT (c), MGMT (d), and DNMT1 (b) were meaningfully different between PTC cases and controls. However, the most significant differences were seen in circulating ctDNA MGMT (c) which was hypermethylated in 25 (43.9 %) of patients with PTC vs 2 (4. 4 %) of goiter samples. Between two selected DNA methyl transferase, the methylation of MGMT as the maintenance methyltransferase was significantly higher in PTC cases than goiter controls (P-value < .001). The resulting areas under the receiver operating characteristic (ROC) curve were 0.78 for MGMT (d) for PTC versus goiter samples that can represent the overall ability of MGMT (d) methylation status to discriminate between PTC and goiter patients.

CONCLUSION

Among seven candidate regions of ctDNA the MGMT (c) and MGMT (d) showed higher sensitivity and specificity for PTC as a suitable candidates as biomarkers of PTC.

Mitotane induces mitochondrial membrane depolarization and apoptosis in thyroid cancer cells

Mitotane is used for the treatment of adrenocortical cancer and elicits its anticancer effects via inhibition of mitochondrial respiration. Targeting mitochondria‑dependent metabolism has emerged as a promising strategy for thyroid cancer (TC) treatment. We hypothesized that mitotane targets mitochondria and induces apoptosis in TC cells. Cell lines representative of the major histological variants of TC were chosen: Follicular (FTC‑133), poorly differentiated (BCPAP), anaplastic (SW1736 and C643) and medullary (TT) TC cells, and were treated with mitotane (0‑100 µM). Mitochondrial membrane potential, cell viability and apoptosis were examined by JC‑1 staining and by western blot analysis using an antibody against caspase‑3. The expression of mitochondrial molecules and DNA damage markers and the activation of endoplasmic reticulum (ER) stress were determined by western blotting. The expression of mitochondrial ATP synthase subunit β (ATP5B) was examined by immunostaining in 100 human TC tissue samples. Treatment with mitotane (50 µM for 24 h) decreased the viability of FTC‑133, BCPAP, SW1736, C643 and TT cells by 12, 59, 54, 31 and 66%, respectively. Morphological evidence of ER stress and overexpression of ER markers was observed in TC cells following exposure to mitotane. The treatment led to increased expression of histone γH2AX, indicating DNA damage, and to caspase‑3 cleavage. Consistent with the results of the cell viability assays, the overexpression of pro‑apoptotic genes following treatment with mitotane was more prominent in TC cells harboring mutations in the serine/threonine‑protein kinase B‑raf gene and proto‑oncogene tyrosine‑protein kinase receptor Ret. Treatment with mitotane was associated with loss of mitochondrial membrane potential and decreased expression of ATP5B, particularly in the medullary TC (MTC)‑derived TT cells. Immunohistochemical analysis of mitochondrial ATP5B in human TC specimens demonstrated its overexpression in cancer compared with normal thyroid tissue. The level of ATP5B expression was higher in MTC compared with the follicular, papillary or anaplastic types of TC. Mitotane elicited pleiotropic effects on TC cells, including induction of ER stress, inhibition of mitochondrial membrane potential and induction of apoptosis. The results of the present study suggest that mitotane could be considered as a novel agent for the treatment of aggressive types of TC.

Current trends in the features of male thyroid cancer: Retrospective evaluation of their prognostic value

This study aimed to compare the clinicopathologic characteristics and oncologic outcomes of papillary thyroid cancer (PTC) patients according to sex. Then, we validated prognostic variables to determine whether sex is a significant prognostic factor for PTC.Between January 2007 and December 2010, 1232 men and 7276 women PTC patients underwent surgery. The patient characteristics and 5-year oncologic outcomes were compared. The stepwise Cox proportional hazards model determined the significance of survival variables.Men PTC patients had more lymph node (LN) metastases than women, both in the total (P < .0001) and hemithyroidectomy (P < .0001) patients. Men and women showed similar 5-year recurrence-free survivals, both in total (P = .815) and hemithyroidectomy (P = .148) patients. The tumor size and the number of positive central nodes were associated with tumor recurrence, but not sex.Sex was not an independent prognostic factor for tumor recurrence. Multicenter clinical studies with long-term follow-ups are needed to validate these results.

Semi-quantitative assessment of diffuse hepatic uptake seen in I-131 scans - an indicator of functioning thyroid tissue and disease burden in differentiated thyroid cancer

BACKGROUND

To semi-quantitatively analyze liver uptake of I-131 in diagnostic and post-therapy scans by calculating hepatic to thigh ratios (HTR) and evaluate its clinical significance in management of differentiated thyroid cancer.

METHOD

Two hundred forty-nine patients were included in the study. Hepatic to thigh ratio (HTR) of counts were calculated for 249 diagnostic and 104 post-therapy scans. Patients were divided into six study groups based on their disease status:1-Serum thyroglobulin (serum Tg) negative (serum Tg ≤ 4 ng/dl) and scan negative; 2-Thyroid remnant only; 3-Thyroid remnant and lymph node metastasis; 4- Tg positive (serum Tg > 4 ng/dl) and scan negative; 5-Bone or/and lung metastasis, and 6-Only lymph node metastasis. Comparison of HTR between these groups was done using one-way ANOVA test. Correlation of HTR with serum Tg, serum thyroid stimulating hormone (TSH), anti-thyroglobulin antibody (ATg) titer and therapeutic dose of I-131 was also assessed.

RESULTS

Comparison of HTR between different study groups (1 to 6) showed significant difference in HTR (p = .001). Study group 5 (bone or/and lung metastasis) showed significantly higher mean HTR compared to other groups (p = 0.001). There was only a weak correlation between serum Tg and HTR (r = 0.395). Dose of I-131 administered also had a weak correlation with HTR (r = 0.207).

CONCLUSION

HTR has good correlation with functional status of tumor cells, while it has weak correlation to therapeutic dose of I-131 administered and serum Tg. Increased HTR predicts significant disease burden in the form of distant bone and lung metastasis and may potentially be used as a second prognostic factor apart from serum Tg.

The role of prophylactic central compartment lymph node dissection in elderly patients with differentiated thyroid cancer: a multicentric study

BACKGROUND

Prophylactic central neck lymph-nodes dissection is still a topic of major debate in Literature. There is a lack of randomized controlled trials proving advantages in its application in terms of overall survival and local recurrence. Due to the recent rapid increase of elderly population, differentiated tumor carcinoma diagnosis increased in patients over 65 years old. The aim of this study was to compare recurrence rate, complications rate and histological features of tumors in elderly population.

METHODS

A retrospective study was carried out collecting data from 371 patients with differentiated thyroid cancer without clinical evidence of lymph-nodes involvement in three Italian referral centers from 2005 to 2015. All patients were aged ≥ 65 years and were divided in two groups based on the performed surgery (total thyroidectomy alone or associated with central lymph-nodes dissection). Moreover, patients were stratified according to the age between 65 and 74 years old and over 75 years old.

RESULTS

Total thyroidectomy alone was performed in 184 patients (group A) and total thyroidectomy with prophylactic central neck dissection was performed in 187 cases (group B). There was a statistically significant difference in complications between the groups in terms of neck hematoma (0.5% group A vs 3.7% group B), temporary hypoparathyroidism (11.4% group A vs 21.4% group B), and temporary unilateral recurrent nerve injury (1.5% group A vs 6.4% group B). Lymph nodes recurrence rate was 9.2% in group A and 8.5% in group B, with no statistically significant difference. There was a statistically significant difference in patients over 75 years old in terms of temporary hypoparathyroidism (24% group A vs 11% group B), permanent hypoparathyroidism (2,7% group A vs 0,3% group B) and recurrent nerve injury (9,5% group A vs 2% group B).

CONCLUSIONS

The role of prophylactic central neck dissection is still controversial, especially in elderly patients, and an aggressive surgical approach should be carefully evaluated. The Authors reported a similar low recurrence rate between total thyroidectomy and total thyroidectomy associated with prophylactic central neck dissection, with increased postoperative complications in the lymphadenectomy group and in patients over 75 years old, advocating a tailored surgical approach in elderly population.

BRAF V600E Status and Stimulated Thyroglobulin at Ablation Time Increase Prognostic Value of American Thyroid Association Classification Systems for Persistent Disease in Differentiated Thyroid Carcinoma

BACKGROUND

Stimulated thyroglobulin levels measured at the time of remnant ablation (A-hTg) and BRAFV600E mutation had shown prognostic value in predicting persistent disease in differentiated thyroid cancer (DTC). The aim of this study was to evaluate the prognostic role of A-hTg combined with the BRAFV600E status in association with the revised American Thyroid Association (ATA) risk stratification.

MATERIAL AND METHODS

620 patients treated for a DTC were included in this study with a median follow-up duration of 6.1 years. All patients underwent total thyroidectomy followed by radioiodine ablation. Patients with positive anti-thyroglobulin antibodies were excluded. The predictive value of A-hTg was calculated by receiver operating characteristic curve (ROC curve) analysis. The Cox proportional hazard regression model, including the BRAF status, A-hTg, and ATA classification system, was assessed to evaluate the existing persistent disease risk.

RESULTS

Taken together, the BRAF status and A-hTg levels improve the ATA risk classification in all categories. In particular, in the low-risk ATA classification, only the combination of BRAFV600E+A-hTg > 8.9ng/ml was associated with persistent disease (P = 0.001, HR 60.2, CI 95% 5.28-687). In the intermediate-risk ATA classification, BRAFWT+A-hTg > 8.9ng/ml was associated with persistent disease (P = 0.029, HR 2.71, CI 95% 1.106-6.670) and BRAFV600E+A-hTg > 8.9ng/ml was also associated with persistent disease (P < 0.001, HR 5.001, CI 95% 2.318-10.790). In the high-risk ATA classification, both BRAFV600E+A-hTg < 8.9ng/ml and BRAFV600E+A-hTg > 8.9 ng/ml were associated with persistent disease (P = 0.042, HR 5.963, CI 95% 1.069-33.255 and P = 0.002, HR 11.564, CI 95% 2.543-52.576, respectively).

CONCLUSIONS

The BRAF status and stimulated thyroglobulin levels at ablation time improve the ATA risk stratification of differentiated thyroid cancer; therefore, even A-hTg could be included in risk classification factors.

Bone Metastases from Thyroid Carcinoma of Follicular Origin: A Single Institutional Experience

BACKGROUND/AIMS

Overall, 2-13% of patients with thyroid cancer develop bone metastases (BM). In addition to decreased survival, patients with BM may present skeletal-related events (SRE) that impair the quality of life. Our objectives were to characterize clinical features, treatment approaches, and outcomes of patients with thyroid cancer and BM.

MATERIAL AND METHODS

We identified patients diagnosed with thyroid carcinoma of follicular origin and BM followed at the Instituto Português de Oncologia de Lisboa Francisco Gentil (IPOLFG), Lisbon, Portugal, from 1991 to 2017. SRE were defined as the need for bone irradiation, bone surgery, spinal cord compression, or pathologic fractures.

RESULTS

The final cohort consisted of 86 patients, with a median follow-up time of 54 months (IQR 22.8-82.8), mainly women (67.4%), and a median age of 64 years (IQR 53.6-71.2). BM was the initial presentation of thyroid cancer in 36.0% of the patients. Bone involvement was multiple in 59.3% of the cases. Papillary carcinoma was the most frequent histological type, present in 47.7% of the patients, of which 56.1% presented the follicular variant. SRE were found in 76.7% of the patients. The most frequent SRE was radiotherapy (66.3%). Treatment with bisphosphonates was initiated in 19.8% of the patients. The 5-year specific survival was 60%, whereas the 10-year specific survival decreased to 50%. There were no differences in 5- or 10-year specific survival regarding gender, the occurrence of SRE, or histological type. However, patients with initial radioiodine non-avid lesions had a lower 5- and 10-year specific survival (p = 0.002).

DISCUSSION

The high frequency of patients with SRE was notable. The follicular variant of papillary thyroid cancer was the variant most commonly associated with BM, reflecting a more similar behavior to follicular carcinoma than the classic variant.

Preoperative charcoal suspension tattoo for the detection of differentiated thyroid cancer recurrence

Recurrent differentiated thyroid carcinoma can easily be detected by means of ultrasound (US) and thyroglobulin, and often requires further surgical intervention. Revision surgery is often a technical challenge with significant risk of complications, considering the altered anatomy, with a possibility of leaving behind residual neoplasm. Preoperative US-guided tattooing localization has been introduced to reduce and prevent these potential problems during revision surgery. Encouraging results have been reported in the literature. Under US guidance, the lesion is identified and 0.5-2 ml of colloidal charcoal is injected in its proximity using a 23 gauge needle. The extraction is accompanied by injection at constant pressure of charcoal in order to leave a trace of pigment along the path of the needle till the skin. From April 2008 to January 2016 we performed revision surgery in 27 patients for lymph-nodes metastasis in differentiated thyroid cancer, using the technique of preoperative charcoal tattoo localization. Our previous study on the first group of 13 patients published in 2012, reported the preliminary results in terms of success rate and complications. The tolerance of charcoal injection was good for all patients and the procedure was demonstrated to be useful, contributing to the removal of metastatic lesion in 93% of procedures. We have registered minor surgical complications during revision in the central compartment of the neck: Transitory hypoparathyroidism in 2 cases (11%) and transitory vocal cord paresis in 3 cases (16%). Based on these results, preoperative charcoal tattoo localization in revision surgery of the neck for differentiated thyroid cancer recurrence can be considered a safe technique, easy to perform, with low-costs and useful during surgical procedures, providing a significant reduction of iatrogenic damage and risks.

Human exposure to bisphenol AF and diethylhexylphthalate increases susceptibility to develop differentiated thyroid cancer in patients with thyroid nodules

Pollutants represent potential threats to the human health, being ubiquitous in the environment and exerting toxicity even at low doses. This study aims at investigating the role of fifteen multiclass organic pollutants, assumed as markers of environmental pollution, most of which exerting endocrine-disrupting activity, in thyroid cancer development. The increasing incidence of differentiated thyroid cancer (DTC) may be related to the rising production and environmental dissemination of pollutants. Fifty-five patients, twenty-seven with diagnosis of benign thyroid nodules and twenty-eight suffering from differentiated thyroid cancer, were enrolled and the concentration levels of seven bisphenols, two phthalates (i.e. di(2-ethylhexyl) phthalate (DEHP) and its main metabolite, mono-(2-ethyl-hexyl) phthalate) (MEHP)), two chlorobenzenes, (1,4-dichlorobenzene and 1,2,4,5-tetrachlorobenzene), and 3 phenol derivatives (2-chlorophenol, 4- nonylphenol, and triclosan) were determined in their serum by using a validated analytical method based on high performance liquid chromatography with ultraviolet tandem fluorescence detection. A significant relationship was found between malignancy and the detection in the serum of both bisphenol AF and DEHP. Indeed, their presence confers a more than fourteen times higher risk of developing differentiated thyroid cancer. Relationship between these two pollutants and the risk of malignancy was dose-independent and not mediated by higher thyroid stimulating hormone levels. Even if a conclusive evidence cannot still be drawn and larger prospective studies are needed, the exposure to low doses of environmental endocrine-disrupting contaminants can be considered consistent with the development of thyroid cancer.

Long-Term Efficacy of Lymph Node Reoperation for Persistent Papillary Thyroid Cancer: 13-Year Follow-Up

BACKGROUND

Current recommendations for persistent or recurrent locoregional papillary thyroid cancer (PTC) include consideration of surgical resection versus active surveillance. The purpose of this study is to determine long-term outcomes after surgical resection of recurrent or persistent metastatic PTC in cervical lymph nodes after failure of initial surgery and radioactive iodine therapy using newer validated clinical outcomes measures.

METHODS

Outcomes of 70 patients who underwent cervical lymphadenectomy (n = 110) from 1999 to 2013 for recurrent or persistent locoregional PTC metastases were reviewed. Measures included biochemical remission (BCR) based on Tg levels, American Thyroid Association classifications for response to treatment [biochemical incomplete response (BIR), structural incomplete response (SIR), indeterminate response (IR), and excellent response (ER)], need for reoperation, surgical complications, disease progression, and death.

RESULTS

The median follow-up was 13.1 years, with only two additional reoperations since 2010, one of which had no metastasis on pathology with the other developing anaplastic thyroid cancer in background PTC. ER was achieved in 31 (44%) patients, all of whom remained in ER at time of last follow-up (median 14.1 years). There were no structural recurrences in patients with persistent BIR or IR after reoperation. Patients with SIR had stable disease, except for one who died due to anaplastic thyroid cancer.

CONCLUSIONS

Patients who achieved ER after reoperation had no need for further treatment. Patients with persistent detectable Tg levels after reoperation rarely developed structural recurrence. ATA outcomes can be safely used to guide treatment decisions over a decade after reoperation for PTC.

CircRNA circ_0067934 Overexpression Correlates with Poor Prognosis and Promotes Thyroid Carcinoma Progression

BACKGROUND Circular RNAs are important regulators in human cancers, including thyroid carcinoma. The circ_0067934 RNA is reported to participate in hepatocellular carcinoma, esophageal squamous cell carcinoma, and lung cancer. Whether it regulates thyroid carcinoma remains unclear. The purpose of this study was to research potential mechanisms of circ_0067934 in thyroid tumors to provide potential new diagnostic and treatment targets. MATERIAL AND METHODS The expression level of circ_0067934 in thyroid tumors, adjacent tissues, and cell lines was measured by qRT-PCR. The Kaplan-Meier survival curve analysis was used to explore the relationship between circ_0067934 level and survival time of patients. Circ_0067934 was knocked down to research its functional role in thyroid tumors. Cell proliferation was detected by CCK-8 (cell counting kit-8) assay. Migration and invasion were analyzed by Transwell assay. Western blot was applied to analyze the expression of epithelial-mesenchymal-transition (EMT) and PI3K/AKT related proteins. RESULTS Compared with adjacent tissue, circ_0067934 was highly expressed in thyroid tumors. Circ_0067934 expression level was highly expressed in thyroid tumor cell lines. Patients with high expression of circ_0067934 showed lower survival rates. Knockdown of circ_0067934 inhibited cell proliferation, migration, and invasion and also promoted apoptosis. In addition, circ_0067934 knockdown inhibited EMT and PI3K/AKT signaling pathways. CONCLUSIONS circ_0067934 could improve the development of thyroid carcinoma by promoting EMT and PI3K/AKT signaling pathways.

Correlations of lncRNAs with cervical lymph node metastasis and prognosis of papillary thyroid carcinoma

Background

Cervical lymph node metastasis is an important prognostic indicator for papillary thyroid carcinoma (PTC) and affects treatment strategies for PTC. lncRNAs essentially contribute to the biological functions of tumors. This study aimed to identify the lncRNAs associated with cervical lymph node metastasis and prognosis of PTC and their potential pathophysiological mechanisms.

Materials and methods

PTC-associated lncRNAs were selected from The Cancer Genome Atlas database, and correlations among lncRNAs, lymph node metastasis, tumor staging, and prognosis of PTC were analyzed in silico. These correlations were then validated through quantitative reverse transcription PCR (qRT-PCR) and immunohistochemistry (IHC).

Results

In silico analysis showed that FAM95B1 and UCA1 were significantly correlated with cervical lymph node metastasis, tumor staging, and PTC prognosis (P<0.05). qRT-PCR analysis revealed high UCA1 expression in PTC tissues and correlations between UCA1 expression levels and cervical lymph node metastasis and tumor staging in PTC, that is, higher UCA1 expression resulted in poorer PTC prognosis. IHC analysis revealed that a high expression of UCA1 was accompanied by a high expression of metastasis-related proteins (MMP-2 and MMP-9), thereby validating the correlation of UCA1 expression with metastasis.

Conclusion

FAM95B1 and UCA1 expression was significantly correlated with the occurrence and progression of PTC. The expression levels of UCA1 significantly affected the prognosis of PTC patients and were significantly correlated with tumor staging and cervical lymph node metastasis.

Low dose radiation regulates BRAF-induced thyroid cellular dysfunction and transformation

Background

The existence of differentiated thyroid cells is critical to respond radioactive iodide treatment strategy in thyroid cancer, and loss of the differentiated phenotype is a trademark of iodide-refractive thyroid disease. While high-dose therapy has been beneficial to several cancer patients, many studies have indicated this clinical benefit was limited to patients having BRAF mutation. BRAF-targeted paired box gene-8 (PAX8), a thyroid-specific transcription factor, generally dysregulated in BRAF-mutated thyroid cancer.

Methods

In this study, thyroid iodine-metabolizing gene levels were detected in BRAF-transformed thyroid cells after low and high dose of ionizing radiation. Also, an mRNA-targeted approach was used to figure out the underlying mechanism of low (0.01Gyx10 or 0.1Gy) and high (2Gy) radiation function on thyroid cancer cells after BRAF^V600E mutation.

Results

Low dose radiation (LDR)-induced PAX8 upregulation restores not only BRAF-suppressive sodium/iodide symporter (NIS) expression, one of the major protein necessary for iodine uptake in healthy thyroid, on plasma membrane but also regulate other thyroid metabolizing genes levels. Importantly, LDR-induced PAX8 results in decreased cellular transformation in BRAF-mutated thyroid cells.

Conclusion

The present findings provide evidence that LDR-induced PAX8 acts as an important regulator for suppression of thyroid carcinogenesis through novel STAT3/miR-330-5p pathway in thyroid cancers.

Electronic supplementary material

The online version of this article (10.1186/s12964-019-0322-x) contains supplementary material, which is available to authorized users.

Features and trends of thyroid cancer in patients with thyroidectomies in Beijing, China between 1994 and 2015: a retrospective study

OBJECTIVES

This study aims to summarise the features and trends of thyroid carcinoma in the past two decades in China.

DESIGN, SETTING AND PARTICIPANTS

Clinical data obtained from 10 798 patients treated by thyroidectomy from 1994 to 2015 at the Department of General Surgery of the People's Liberation Army General Hospital, Beijing, China were retrospectively analysed.

OUTCOME MEASURES

Incidence and histopathological features of thyroid cancer were compared and the risk factors for local lymph node metastasis analysed.

RESULTS

Our data indicated a significant increase in the detection of thyroid cancer (from 16.8% to 69.8%, p<0.01). Among the 5235 thyroid cancer cases, papillary thyroid carcinoma (PTC) was the most common histotype, accounting for 95.1% of all malignancies over the 22-year period. Among the 4979 PTCs, micro-PTCs (mPTC) with the largest diameter ≤10 mm has gradually become the dominant form, and its percentage in PTCs has increased from 13.3% in the biennial period of 1994-1995 to 51.2% in 2010-2011. Furthermore, the size of the tumour has decreased significantly from 2.3±1.1 cm in 1994 to 1.2±0.9 cm in the largest diameter (p<0.01), while the average age at diagnosis and female dominance remained unchanged during the period. Logistic regression showed that tumour nodules>1 cm and male gender were the main risk factors for local lymph node metastasis (LNM), whereas patients over 45 years had lower risk.

CONCLUSIONS

During the 22-year period, an increased detection of thyroid cancer, particularly mPTC, was found while the occurrence of LNM decreased. Our results suggest that the current preoperative diagnosis and risk stratification are adequate, supporting the published guidelines for the diagnosis of thyroid cancer.

TERT promoter mutations identify a high-risk group in metastasis-free advanced thyroid carcinoma

BACKGROUND

TERT promoter mutations are associated with adverse clinicopathological characteristics in thyroid carcinomas and considered as a major indicator of poor outcomes. Nevertheless, most studies have pooled heterogeneous types of thyroid carcinomas and have been conducted retrospectively. We investigated the association between TERT promoter mutations and recurrence in a prospective series of 173 intermediate- to high-risk patients with thyroid cancer.

PATIENTS

Patients referred for radioiodine treatment after thyroidectomy for intermediate- to high-risk differentiated thyroid carcinoma were included in a prospective observational study and tested for TERT promoter, BRAF, and RAS mutations of their primary tumours. We analysed the relationship between TERT promoter mutations and outcomes.

RESULTS

The prevalence of TERT promoter mutations was 20.2% (35/173) in the total population. It was significantly higher in tumours harbouring aggressive histological features (poorly differentiated carcinoma, tall cell variant of papillary cancer or widely invasive follicular cancer) than in non-aggressive tumours: 32.7% (16/49) versus 15.3% (19/124; p = 0.020). TERT promoter mutations were also strongly associated with age ≥45 years (p = 0.005), pT4 stage (p = 0.015), metastatic disease (p = 0.014), and extrathyroidal extension (p = 0.002). TERT promoter mutations were associated with poor outcomes in the total population (p < 0.001) but not in the subgroup of non-metastatic patients (p = 0.051). However, they were associated with a worse outcome in patients both free of metastases and devoid of aggressive histological features. Neither BRAF nor RAS mutations were associated with event-free survival in non-metastatic patients.

CONCLUSION

Although their prognostic value does not seem to overcome that of histology, TERT promoter mutations may help to better define the prognosis of localized thyroid cancer patients without aggressive histology.

Safety of Tyrosine Kinase Inhibitors in Patients With Differentiated Thyroid Cancer: Real-World Use of Lenvatinib and Sorafenib in Korea

Background: Thyroid cancer has become the most common cancer in Korea. Generally, thyroid cancer patients have a good prognosis; however, 15-20% of patients experience recurrence or distant metastasis or are refractory to standard treatment. We assessed the safety of sorafenib and lenvatinib in patients with advanced or metastatic radioactive iodine-refractory differentiated thyroid cancers (DTC) consecutively treated at a tertiary center in South Korea. Methods: We retrospectively reviewed the charts of all consecutive patients with DTC treated during ≥6 months with lenvatinib (February 2016-April 2018) and sorafenib (January 2014-April 2018) at Gangnam Severance Hospital. Patients were treated according to the prescribing information of each drug and were followed up for 2 months. We evaluated the adverse events (AEs) reported with each drug. Results: A total of 71 medical records (lenvatinib, n = 23; sorafenib, n = 48) were reviewed. The most common histological types were papillary thyroid cancer (69.0%) and follicular thyroid cancer (22.5%). All patients (n = 23) started lenvatinib at a dose of 20 mg; 41.7% of sorafenib-treated patients received an initial dose of 800 mg daily. Four (17.4%) lenvatinib-treated patients and 26 (54.2%) sorafenib-treated patients required treatment discontinuation. The most common AEs of any grade in the lenvatinib group were diarrhea (82.6%), hypertension (78.3%), hand-foot skin reaction (56.5%), weight loss (52.2%), proteinuria (47.8%), and anorexia (43.5%). In the sorafenib group, these were hand-foot skin reaction (87.5%), diarrhea (62.5%), anorexia (60.4%), alopecia (56.3%), mucositis (52.1%), weight loss and generalized weakness (each, 50%), and hypertension (43.8%). The incidence of hand-foot skin reaction, alopecia, and rash of any grade was significantly lower (P = 0.003, P = 0.017, and P = 0.017) in patients treated with lenvatinib compared with those treated with sorafenib. The incidence of hypertension, QT prolongation, and proteinuria of any grade was significantly higher (P = 0.006, P = 0.038, and P < 0.001) in patients treated with lenvatinib compared with those treated with sorafenib. Seven deaths occurred, which were attributed to disease progression. Conclusions: No new safety concerns were identified for either drug. Most AEs were managed with dose modification and medical therapy. AEs such as hypertension and proteinuria warrant close monitoring.

Re-treatment With Adjuvant Radioactive Iodine Does Not Improve Recurrence-Free Survival of Patients With Differentiated Thyroid Cancer

Introduction: Loco regional persistence or recurrence of differentiated thyroid cancer (DTC) is frequent despite initial thyroidectomy and radioactive iodine therapy (RAI). The aim of this study was to analyze the impact of a complementary adjuvant RAI (Ad-RAI) on disease recurrence following re-operation on patients with locally persistent or recurrent DTC. Patients and Methods: A retrospective study of 85 patients with DTC was conducted. All patients were initially treated with total thyroidectomy and RAI, and re-operated for a locally persistent or recurrent disease. Propensity score was calculated to predict the impact of Ad-RAI on survival after reoperation, and to reduce the bias of the limited sample size and the prognostic tests. Results: 49 (58%) patients were re-treated with Ad-RAI after re-operation while 36 (42%) were only followed up. Disease recurrence after re-treatment (re-operation ± Ad-RAI) was detected in 31 patients (36.5%). In multivariate analysis, age >55 years (HR: 3.9 [1.6; 9.5]; p < 0.00001) was the main poor prognostic factor for recurrence-free survival. Three parameters independently influenced the decision to administer ad-RAI: low number of previous RAI administrations, Nx before re-operation, and pTg > 30 μg/l. These parameters were incorporated in the Propensity score calculation. If ad-RAI tended to improve recurrence-free survival (median survival 17.4 vs. 10.9 months), adjustment using the Propensity score removed any difference between the groups (p = 0.54), confirming the limited value of ad-RAI. Conclusion: In patients with locally persistent or recurrent DTC, age is the main independent prognostic factor. Adjuvant RAI does not improve recurrence-free survival of DTC patients.

Follicular thyroid carcinoma metastatic to skin: a small papule and a big diagnostic change

Cutaneous metastases are uncommon in daily practice, although very important, since they may be the first manifestation of an undiscovered primary neoplasm or the first indication of recurrence. Cutaneous metastases from the breast are the most frequent in women and cutaneous metastases from the lung are the most frequent in men. Thyroid carcinoma, despite representing the most frequent endocrine neoplasm, is considered a rare neoplasm, corresponding to 1% of malignant neoplasms diagnosed. Cutaneous metastases from follicular carcinoma are rare and occur mainly in the head and neck area. We report a case of cutaneous metastasis in a patient with follicular thyroid carcinoma and breast carcinoma. Because of the association of these two neoplasms, the possibility of Cowden Syndrome - multiple hamartoma syndrome - was raised, but was excluded by genetic analysis of PTEN gene.

Cystathione β-Synthase Is Increased in Thyroid Malignancies

BACKGROUND

Cystathione β-synthase (CBS) catalyzes the conversion of homocysteine and cysteine to hydrogen sulfide (H₂S) and cystathione, via the trans-sulfuration pathway. CBS protein expression levels are increased in several different human malignancies, with increased protein expression correlating with parameters such as tumor stage, anaplasia, metastases, and chemotherapy resistance.

MATERIALS AND METHODS

This study employed tissue microarrays to examine CBS expression in benign thyroid tissue, thyroid oncocytomas, thyroid follicular adenomas, and in follicular, papillary, anaplastic, and medullary thyroid carcinomas.

RESULTS

CBS expression was increased in all thyroid carcinomas types compared to benign thyroid tissue, but not in thyroid follicular adenomas or oncocytomas. A similar pattern was observed for nicotinamide phosphoribosyltransferase (NAMPT) tissue microarray analysis comparing thyroid adenomas and follicular carcinomas.

CONCLUSION

For the first time, we showed that an H₂S-syntheszing enzyme plays a role in thyroid malignancies. Additionally, our data suggest that CBS and NAMPT immunohistochemistry may be useful in differentiating follicular adenomas from follicular carcinomas.

Clinical Outcomes of Differentiated Thyroid Cancer Patients with Local Recurrence or Distant Metastasis Detected in Old Age

BACKGROUND

Differentiated thyroid carcinoma (DTC) shows a very good prognosis, but older patients have a higher recurrence rate and those show poor prognosis than younger patients. The aim of this study was to determine the clinical outcomes of thyroid cancer patients who experienced recurrence in old age according to the treatment strategy used.

METHODS

This retrospective observational cohort study was conducted at Asan Medical Center, Seoul, Korea. Among DTC patients with no evidence of disease after initial treatment, we enrolled 86 patients who experienced recurrence at an age >65 years from 1994 to 2012. Sixty-nine patients had local recurrence and 17 patients showed distant metastasis.

RESULTS

The mean age of patients at recurrence was 72 years. Patients were followed up for a median of 4.1 years after recurrence. Sixty-three of the 69 patients with local recurrence received additional treatment, while the other six received conservative care. The cancer-specific mortality rate was 15.5% in the local recurrence group. Airway problems were the main cause of death in patients who did not receive further treatment for local recurrence. Among the 17 patients with distant metastasis, 10 underwent specific treatment for metastasis and seven received only supportive management. Seven of those 17 patients died, and the cancer-specific mortality rate was 35% in the distant metastasis group.

CONCLUSION

The overall cancer-specific mortality rate was 20% in DTC patients in whom recurrence was first detected at an age >65 years. Mortality due to uncontrolled local disease occurred frequently in patients who did not receive definitive management for recurrence.

Estimation of blood and bone marrow doses of thyroid carcinoma patients treated with 131I through gamma spectrometry

¹³¹I therapy is the treatment for patients with differentiated thyroid carcinoma (DTC) to ablate remnant thyroid tissue after surgery. The aim of this study was to estimate the absorbed doses to the blood and bone marrow of patients with DTC using gamma spectrometry. The evaluation of the absorbed dose in blood and bone marrow is a good indicator of a patient's response and its radiological protection. The average of low activities administered (AAAL) to ten patients was 3.20 GBq and the average of high activities administered (AAAH) to eight patients was 4.95 GBq. The blood and bone marrow doses were determined according to Lassmann et al 2008, performing successive measurements of activity in blood samples and whole body. Blood samples of 2 ml were taken during the first 48 h; the first one was extracted 2 h after the administration of the capsule and the following ones were taken every 12 h. The whole-body measurements were made at regular intervals of time throughout the patient's isolation period using a mobile gamma spectrometry system located inside the isolation room of the Dr Hernán Henríquez Aravena Hospital. The average residence times in blood and whole-body were (6.9 ± 1.7) × 10^-4 h ml^-1 and (23.2 ± 4.5) h, respectively. The average doses in blood and bone marrow of patients with AAAL were (0.33 ± 0.09) Gy and (0.63 ± 0.18) Gy, respectively, and with AAAH were (0.48 ± 0.06) Gy and (0.87 ± 0.19) Gy, respectively. In all studied patients, the bone marrow doses were less than 2 Gy. The results were compared with the previously published values, finding some differences between the residence times and significant differences in the doses, which show the need to compare the different methodologies.

NMR-based metabolomics to select a surgical method for treating papillary thyroid carcinoma

OBJECTIVE

This study aims to investigate differences in the metabolomic profiles of patients who received different surgeries for papillary thyroid carcinoma (PTC).

METHODS

Two surgical methods, i.e., unilateral and total thyroidectomy, were employed according to different disease conditions. Sera from patients who were treated with levothyroxine sodium tablets before and after surgery was analyzed with a Bruker 500 Hz nuclear magnetic resonance (NMR) spectrometer. Data were analyzed via principal component analysis (PCA) and partial least squares discriminate analysis (PLS-DA) with SIMCA-P+ 11.0 software, and metabolites were obtained and compared. The first and second principal components were selected from PCA, PLS-DA, and orthogonal partial least squares discriminate analysis (OPLS-DA). A p-value less than 0.05 was considered statistically significant.

RESULTS

There were significant differences in serum metabolomics before and after surgery. Compared with unilateral thyroidectomy, total thyroidectomy reversed some highly increased metabolite levels (e.g., taurine and betaine). More significant variations in abnormal metabolites were noted after total thyroidectomy than after unilateral thyroidectomy (e.g., alanine, choline, hippurate, and formic acid).

CONCLUSIONS

The choice of surgical method for PTC patients should be based not only on the tumor condition but also on the potential consequences of metabolic variations. Total thyroidectomy reversed some increased metabolite levels but led to accumulation of some other metabolites due to the loss of thyroid function; thus, metabolic disturbances caused by thyroid hormone deficiency should be prevented in advance.

Clinical Status and Treatment of Liver Metastasis of Differentiated Thyroid Cancer Using Tyrosine Kinase Inhibitors

BACKGROUND

Treatment of patients with liver metastasis of differentiated thyroid carcinoma (DTC) has not been sufficiently defined, because liver metastasis of DTC has been described mostly as case reports. Additionally, such patients are considered end-of-treatment responders. A relatively new approach using tyrosine kinase inhibitors (TKIs) may provide opportunities to manage systemic metastasis. This study aims to define the clinical features of DTC patients with liver metastasis and evaluate the benefits of TKIs.

METHODS

We retrospectively analyzed clinical features of 29 patients (mean age 67.8 years) diagnosed with liver metastasis of DTC at our institution between January 1981 and May 2017.

RESULTS

All patients had distant metastasis at other organ sites upon diagnosis of liver metastasis; 41% of them developed new metastasis afterward. Management after diagnosis of liver metastasis comprised palliative care (48%), radioactive iodine therapy (28%), and TKI therapy (24%). The median survival after diagnosis of liver metastasis was only 4.8 months. Survival rates were significantly better in patients with performance statuses between 0 and 2 on the Eastern Cooperative Oncology Group scale at diagnosis of liver metastasis (n = 22, 76%) treated with TKI compared to those who were not (P = 0.017; log-rank test; hazard ratio 0.19). One-year survival rates were 71.4 and 26.7% for patients treated with or without TKI, respectively.

CONCLUSIONS

Patients with liver metastasis had poor clinical prognosis. When other distant metastases existed at diagnosis of liver metastasis, TKI therapy was considered an effective therapeutic option for patients with liver metastasis of DTC.

Evaluation of Bone Mineral Density Using DXA and cQCT in Postmenopausal Patients Under Thyrotropin Suppressive Therapy

PURPOSE

This study aimed to examine the discrepancy in osteoporosis diagnoses between central quantitative computed tomography (cQCT) and dual-energy X-ray absorptiometry (DXA) and evaluated correlations among volumetric bone mineral density (vBMD), areal bone mineral density (aBMD), and trabecular bone score(TBS) in postmenopausal women who were undergoing TSH suppressive therapy.

METHODS

We enrolled a total of 81 postmenopausal patients [median age: 58 years; interquartile range (IQR): 57 to 60 years] receiving TSH suppressive therapy with levothyroxine after undergoing total thyroidectomy for papillary thyroid cancer. Patients were diagnosed by their bone mineral density (BMD) T-score and categorized according to a vBMD threshold of 120 mg/cm3 for osteopenia and a threshold of 80 mg/cm3 for osteoporosis.

RESULTS

When DXA and cQCT were compared, the BMD evaluation results differed in 76% of patients (n = 62; P < 0.001), and the detection rate of osteoporosis was 30.9% for cQCT and 21.0% for DXA. Sixty-two patients had discordant results; in 46 of these patients (74%) whose DXA T-scores were normal, the diagnosis shifted to osteopenia (n = 35) and osteoporosis (n = 11) according to the vBMD on cQCT (P < 0.001), and their vBMD values were significantly correlated with TBS (r = 0.293; P = 0.008). However, aBMD was not significantly correlated with TBS (r = 0.080; P = 0.480). TBS was significantly lower in patients with osteopenia (median: 1.35; IQR: 1.18 to 1.47) and osteoporosis (median: 1.28; IQR: 1.07 to 1.47) than in those with a normal BMD value (median: 1.37; IQR: 1.25 to 1.49; P = 0.041) on cQCT. There was no significant difference in TBS according to DXA BMD status (P = 0.200).

CONCLUSIONS

DXA and cQCT yielded inconsistent results, and detection of osteopenia and osteoporosis was higher using cQCT. TBS showed a more significant correlation with vBMD than with aBMD.

Sonographic Evaluation of Nodules Newly Detected in the Neck After Thyroidectomy: Suture Granuloma Versus Recurrent Carcinoma

Purpose

This study aimed to clarify the sonographic features of suture granuloma and recurrent carcinoma newly detected after thyroidectomy.

Materials and Methods

We retrospectively analyzed ultrasound reports with images of 25 cases of suture granuloma and 18 cases of recurrent carcinoma that newly appeared in the resected area after thyroidectomy in our institution.

Results

Both suture granulomas and recurrent carcinomas more frequently exhibited multiple lesions rather than solitary lesions. Suture granulomas tended to appear in the more superficial areas than the carotid artery, while recurrent carcinomas were more common between the trachea and carotid artery. A total of 10 of the 11 suture granulomas that we followed up decreased in size. Recurrent carcinomas showed irregular shape (55.6%), taller-than-wide shape (38.9%), low internal echogenicity (83.3%), and no punctate microcalcifications. By contrast, suture granulomas were fusiform in shape (56.0%) and showed linear internal echo parallel to the tissue plane on the longitudinal scan (64.0%). The vascular flow sign was mild to none in the majority of both lesions.

Conclusion

Fusiform shape and linear internal echoes indicate suture granuloma, while irregular shape, taller-than-wide shape, and low echogenicity indicate recurrent carcinoma. Given that the clinical management of suture granuloma differs from that of recurrent carcinoma, it is important to distinguish between these two lesions.

SoLAT (Sorafenib Lenvatinib alternating treatment): a new treatment protocol with alternating Sorafenib and Lenvatinib for refractory thyroid Cancer

Background

In the last decade, several tyrosine kinase inhibitors (TKIs), which disrupt pathways involved in the proliferation and tumorigenesis of thyroid cancer, have been extensively studied. Two different TKIs, lenvatinib and sorafenib, were recently approved by both the US FDA and European Medicine Agency. Until date, the duration of the TKI response is not sufficient and resistance eventually occurs. The goal of this study was to investigate a new treatment protocol, SoLAT, using sorafenib and lenvatinib alternatively on refractory thyroid cancer.

Methods

Patient-derived aggressive papillary thyroid cancer (PTC) cell lines from patients with biochemical and histologically proven aggressive RAI-refractory papillary thyroid cancer were exposed to sorafenib and lenvatinib alternatively. Human thyroid cancer cell xenografts were obtained by injecting patient-derived aggressive PTC cell lines into the flank of female BALB/c nude mice. Tumor-bearing mice were treated with sorafenib and lenvatinib alternatively. Cell viability assay, immunofluorescence analysis, confocal imaging, immunoblot analysis, flow cytometry analysis of cell cycle and a tube formation assay were performed.

Results

SoLAT was more effective for advanced PTC cell lines than individual treatment. Immunoblot analysis showed that SoLAT markedly increased levels of cell cycle inhibitors (p53 and p21), and pro-apoptotic factors (Apaf-1 and cleaved caspase 3) and decreased levels of positive cell cycle regulators (cyclin D1, CDK4, CDK6) and anti-apoptotic factors (p-NFκB, Bcl-2). Increased sub-G₀/G₁ population was observed in the SoLAT group, leading to apoptosis, cell cycle arrest, and strong inhibition of advanced PTC cell viability. SoLAT reduced the level of EMT markers such as vimentin, E-cadherin, Snail and Zeb1 by FGFR inhibition. In the xenograft model, individual treatment with sorafenib or lenvatinib did not markedly suppress patient-derived aggressive PTC cell xenograft tumors, whereas SoLAT significantly suppressed the proliferation of these tumors.

Conclusions

SoLAT was more effective than individual treatment with sorafenib or lenvatinib in inhibiting PTC progression by inducing cell cycle arrest. Studies using both in vitro cell culture and an in vivo xenograft model provided evidence of tumor shrinkage with SoLAT. We suggest that these effects may be due to reduced EMT-mediated drug resistance in the aggressive PTC model.

Great veins invasion in follicular thyroid cancer: single-centre study assessing prevalence and clinical outcome

PURPOSE

Great veins invasion is considered as a rare and prognostically unfavourable event in thyroid cancer. However, current knowledge about this issue is mainly based on single case reports. Follicular thyroid cancer (FTC) represents the histotype with the most pronounced angioinvasive feature. This study is aimed at assessing the actual prevalence of great veins invasion in FTC and providing information about prognosis and the proper clinical management of these patients.

METHODS

Clinico-pathological and radiological data of patients with thyroid cancer undergoing thyroidectomy in our institution were retrospectively retrieved. Inclusion criteria were as follows: (a) histological diagnosis of FTC; (b) instrumental and histological evidence of great veins invasion and (c) documented follow-up entirely performed at our institution. Pre-surgical assessment of great veins status was performed in all patients by means of Doppler ultrasonography.

RESULTS

Out of 637 patients operated from 2003 to 2013, four subjects, all affected with FTC, showed great veins involvement (0.62% of the overall cohort and 7.85% of the FTC group). One of them was lost at follow-up. All three patients with available follow-up were subjected to aggressive surgery obtaining a complete eradication of neck disease. All of them achieved the 5-year survival target (60, 63 and 96 months of survival for patients 1, 2 and 3, respectively).

CONCLUSIONS

Great veins invasion may not be uncommon in FTC and preoperative detection and characterisation of such condition may optimise surgical approach and improve survival.

Papillary Thyroid Carcinoma Recurrence: Low Yield of Neck Ultrasound With an Undetectable Serum Thyroglobulin Level

OBJECTIVES

To assess the yield of neck ultrasound (US) when serum thyroglobulin (Tg) is undetectable (<0.1 ng/mL) compared to elevated serum Tg in patients with differentiated papillary thyroid carcinoma (PTC) treated with thyroidectomy and radioactive iodine 131 (RAI) ablation.

METHODS

A retrospective chart review was conducted from 2010 through 2015 at an academic institution evaluating US results in patients with serum Tg levels obtained within 6 months of a neck US examination after thyroidectomy and RAI. The reference standard for recurrence was pathologic results from US-guided fine-needle aspiration (FNA) or follow-up for at least 1 year.

RESULTS

Among 76 patients with undetectable serum Tg levels, there were 19 examinations in 18 patients in which US raised the possibility of recurrence. None of these 18 patients had recurrence by FNA (n = 8) or clinical follow-up of at least 1 year (n = 10). Among 65 patients with elevated serum Tg levels, there were 24 examinations in 22 patients in which US raised the possibility of recurrence. Twelve patients underwent FNA, with 9 patients (34.6%) showing PTC; 7 patients had follow-up neck US examinations showing stability of findings; and 3 patients were lost to follow up. The yield of neck US was significantly lower when serum Tg was undetectable compared to when levels were elevated (P = .001).

CONCLUSIONS

Neck US did not identify recurrent PTC when the serum Tg level was undetectable in patients who underwent total thyroidectomy and RAI therapy. Eliminating neck US when serum TG levels are undetectable could decrease unnecessary imaging examinations without negatively affecting the ability to detect recurrent disease.

Unexpected False-positive I-131 Uptake in Patients with Differentiated Thyroid Carcinoma

Objective:

Radioiodine is the most specific radionuclide for differentiated thyroid carcinoma (DTC) imaging. Despite its high specificity and sensitivity, false-positive I-131 uptake could be seen on whole body scan (WBS) that may lead to misdiagnosis and unnecessary radioiodine treatment. In this study, we aimed to present the I-131 WBS and concomitant single photon emission computed tomography/computed tomography (SPECT/CT) images of unexpected false-positive radioiodine uptake along with the patients’ clinical outcomes and the contribution of SPECT/CT imaging.

Methods:

I-131 WBSs of 1507 patients with DTC were retrospectively reviewed, and anticipated I-131 uptakes (like in breasts or thymus) were excluded from the study. The unexpected false-positive I-131 uptakes with concomitant SPECT/CT imaging were included in the study.

Results:

Twenty-one patients had 23 unexpected I-131 uptakes on WBS and concomitant SPECT/CT imaging. The vast majority (87%) of these cases were seen on post-therapeutic I-131 WBS. Most of the false-positive I-131 uptakes could be explained by SPECT/CT and radiologic findings, and were secondary to non-thyroid conditions (bronchiectasis, lung infection, subcutaneous injection into gluteal fatty tissue, aortic calcification, benign bone cyst, vertebral hemangioma, recent non-thyroid surgical procedure site, rotator cuff injury, mature cystic teratoma and ovarian follicle cyst). However, the possible reasons of 9 false-positive I-131 uptakes could not be explained by radiologic findings.

Conclusion:

We suggest that false-positive I-131 uptake and its underlying mechanisms (inflammation, trapping, increased perfusion, etc.) must be kept in mind in patients with thyroid cancer and unexpected findings must be considered together with serum thyroglobulin levels, SPECT/CT and radiologic findings in order to avoid misdiagnosis and unnecessary radioiodine treatment.

Locoregional disease control after external beam radiotherapy in 91 patients with differentiated thyroid carcinoma and pT4 tumor stage - a single institution experience

Background Locoregional recurrence is common in patients with locally advanced differentiated thyroid carcinoma (DTC). Our aim was to find out the rate of locoregional control of the disease after external beam radiotherapy (EBRT) of the neck and mediastinum in patients with DTC and pT4 tumor. Patients and methods Altogether 91 patients (47 males, 44 females, median age 61 years) with DTC had EBRT of the neck and mediastinum as part of the multimodal treatment of pT4 tumor (63 cases pT4a, 28 cases pT4b) from the year 1973 to 2015. Data on clinical factors, histopathology and recurrence were collected. Disease-free, disease-specific and overall survival was calculated. Results Median tumor size was 5 cm (range 1-30 cm). Out of 91 patients, 23 had distant and 38 regional metastases. A total or near-total thyroidectomy, lobectomy, subtotal thyroidectomy and lymph node dissection was performed in 70%, 14%, 2% and 30% of cases, respectively. Thirteen percent of patients were not treated with surgery. All patients had EBRT and 39 had chemotherapy. Radioiodine (RAI) ablation of thyroid remnant and RAI therapy was applied in 90% and 40% of cases, respectively. Recurrence was diagnosed in 29/64 patients without a persistent disease: locoregional and distant in 16 and 13 cases, respectively. Five-year and ten-year disease-free survival rate was 64% and 48%, respectively. Conclusions The majority of patients with DTC and pT4 tumors who were treated with EBRT of the neck and mediastinum region as part of multimodal treatment have long-lasting locoregional control of the disease.

A scoring system to predict recurrence in patients with differentiated thyroid cancer

OBJECTIVES

Though predictive models have been constructed to determine the risk of recurrence in differentiated thyroid carcinoma, various aspects of these models are inadequate. Therefore, we aimed to construct, internally validate and implement on a mobile application a scoring system to determine this risk within 10 years.

DESIGN

A retrospective cohort study in 1984-2016.

SETTING

A Spanish region.

PARTICIPANTS

We enrolled 200 patients with differentiated thyroid carcinoma without distant metastasis at diagnosis.

MAIN OUTCOME MEASURES

Time-to-recurrence. A risk table was constructed based on the sum of points to estimate the likelihood of recurrence. The model was internally validated and implemented as a mobile application for Android.

RESULTS

Predictive factors were follicular histology, T, N and multifocality. This risk table had a C-statistic of 0.723. The calibration was satisfactory.

CONCLUSIONS

This study provides an instrument able to predict rapidly and very simply which patients with differentiated thyroid carcinoma have a greater risk of recurrence.

THYROGLOBULIN AS A TUMOR MARKER IN DIFFERENTIATED THYROID CANCER - CLINICAL CONSIDERATIONS

SUMMARY – Initial treatment of the majority of patients with differentiated thyroid cancer (DTC) includes total thyroidectomy. Postoperative ablation therapy with radioactive iodine (I-131) is indicated in all high-risk patients, however, there is disagreement regarding its use in low- and intermediate-risk patients. Over the last few decades, thyroglobulin (Tg) has been established as the primary biochemical tumor marker for patients with DTC. Thyroglobulin can be measured during thyroid hormone therapy or after thyroid-stimulating hormone (TSH) stimulation, through thyroid hormone withdrawal or the use of human recombinant TSH. In many studies, the cut-off value for adequate Tg stimulation is a TSH value ≥30 mIU/L. However, there is an emerging body of evidence suggesting that this long-established standard should be re-evaluated, bringing this threshold into question. Recently, a risk stratification system of response to initial therapy (with four categories) has been introduced and Tg measurement is one of the main components. The relationship between the Tg/TSH ratio and the outcome of radioiodine ablation has also been studied, as well as clinical significance of serum thyroglobulin doubling-time. The postoperative serum Tg value is an important prognostic factor that is used to guide clinical management, and it is the most valuable tool in long term follow-up of patients with DTC.

Thyroid cancer in adolescents and young adults

In adolescents and young adults, thyroid cancer accounts for 13% of all invasive neoplasms, being three times more frequent in females, but overdiagnosis and overtreatment are common. There are two therapeutic approaches, one radical and no longer preferred in all instances, and the other conservative. Permanent complications of surgery and metabolic irradiation can affect quality of life and carry an economic burden. The overall survival rate approaches 100% for patients with differentiated thyroid cancer regardless of the extent of treatment. Medullary thyroid carcinoma is a very different entity, occurring most frequently in the context of hereditary tumor susceptibility syndromes.

mRNA Expression of SLC5A5 and SLC2A Family Genes in Papillary Thyroid Cancer: An Analysis of The Cancer Genome Atlas

PURPOSE

The present study investigated the dynamics and prognostic role of messenger RNA (mRNA) expression responsible for ¹⁸F-fluorodeoxyglucose (FDG) uptake in FDG positron emission tomography (PET) and radioactive iodine (¹³¹I) uptake in whole-body radioactive iodine scans (WBS) in papillary thyroid cancer (PTC) patients.

MATERIALS AND METHODS

The primary and processed data were downloaded from the Genomic Data Commons Data Portal. Expression data for sodium/iodide symporter (solute carrier family 5 member 5, SLC5A5), hexokinase (HK1-3), glucose-6-phosphate dehydrogenase (G6PD), and glucose transporter (solute carrier family 2, SLC2A1-4) mRNA were collected.

RESULTS

Expression of SLC5A5 mRNA were negatively correlated with SLC2A1 mRNA and positively correlated with SLC2A4 mRNA. In PTC with BRAF mutations, expressions of SLC2A1, SLC2A3, HK2, and HK3 mRNA were higher than those in PTC without BRAF mutations. Expression of SLC5A5, SLC2A4, HK1, and G6PD mRNA was lower in PTC without BRAF mutation. PTCs with higher expression of SLC5A5 mRNA had more favorable disease-free survival, but no association with overall survival.

CONCLUSION

Expression of SLC5A5 mRNA was negatively correlated with SLC2A1 mRNA. This finding provides a molecular basis for the management of PTC with negative WBS using ¹⁸F-FDG PET scans. In addition, higher expression of SLC5A5 mRNA was associated with less PTC recurrence, but not with deaths.

Transcriptomic signature associated with carcinogenesis and aggressiveness of papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) is the fastest-growing disease caused by numerous molecular alterations in addition to previously reported DNA mutations. There is a compelling need to identify novel transcriptomic alterations that are associated with the pathogenesis of PTC with potential diagnostic and prognostic implications. Methods: We gathered and compared 242 expression profiles between paired PTC and adjacent normal tissues and identified and validated the coding and long non-coding RNAs (lncRNAs) associated with the extrathyroidal extension (ETE) of 655 PTC patients in two independent cohorts, followed by predicting their interactions with drugs. Co-expression, RNA interaction, Kaplan-Meier survival and multivariate Cox proportional regression analyses were performed to identify dysregulated lncRNAs and genes that correlated with clinical outcomes of PTC. Alternative splicing (AS), RNA circularization, and editing were also compared between transcriptomes to expand the repertoire of molecular alterations in PTC. Results: Numerous genes related to cellular microenvironment and steroid hormone response were associated with the ETE of PTC. Drug susceptibility predictions of the expression signature revealed two highly ranked compounds, 6-bromoindirubin-3'-oxime and lovastatin. Co-expression and RNA interaction analysis revealed the essential role of lncRNAs in PTC pathogenesis by modulating extracellular matrix and cell adhesion. Eight genes and two novel lncRNAs were identified that correlated with the aggressive nature and disease-free survival of PTC. Furthermore, this study provided the transcriptome-wide landscape of circRNAs in PTC and uncovered dissimilar expression profiles among circRNAs originating from the same host gene, suggesting the functional complexity of circRNAs in PTC carcinogenesis. The newly identified AS events in the SERPINA1 and FN1 genes may improve the sensitivity and specificity of these diagnostic biomarkers. Conclusions: Our study uncovered a comprehensive transcriptomic signature associated with the carcinogenesis and aggressive behavior of PTC, as well as presents a catalog of 10 potential biomarkers, which would facilitate PTC prognosis and development of new therapeutic strategies for this cancer.

Multifocality related factors in papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) is the main type of the well-differentiated thyroid carcinomas. Multifocality is regarded as a poor prognostic factor for PTC.

METHODS

Documents of 777 patients who underwent thyroidectomy were reviewed retrospectively. A total of 305 PTC patients were included. Patients with multifocal PTC were included in Group 1, and patients with unifocal PTC were included in Group 2.

RESULTS

There were 165 patients (54.0%) in Group 1 and 140 patients (46%) in Group 2. The pathological mixed variant of PTC was significantly higher in Group 1 (p = 0,005). Lymph node metastasis (LNM) was detected at 9.6% and 3.5% in Group 1 and Group 2, respectively (p = 0,028). Micro PTC rates were 28.4% and 40.7% in Group 1 and Group 2, respectively (p = 0,017). Tumor size and pathologically mixed-type and fine-needle aspiration biopsy (FNAB) results were significantly different between multifocal and unifocal Micro PTC (p < 0.05).

CONCLUSIONS

Multifocality is more frequent in patients with tumors ≥1 cm and mixed-type tumors. LNM is found more often in multifocal tumors. The presence of micropapillary tumors can be predicted preoperatively by ultrasound-guided FNAB. Mixed-type pathology is also a predictive factor for multifocality.

Ultrasound requested by general practitioners or for symptoms unrelated to the thyroid gland may explain higher prevalence of thyroid nodules in females

BACKGROUND

A higher prevalence of thyroid nodules/carcinoma in females is well-known from the literature. The reasons for this difference are not fully explained. We intended to assess gender variation in the referral for ultrasound-guided fine needle aspiration (FNA) of thyroid nodules, to study reasons for gender referral differences, and to assess differences in nodules characteristics between genders.

METHODS

Included were 272 consecutive patients, with 290 nodules submitted to FNA. Patients were questioned on the reason why ultrasound (US) examination was required. Electronic medical records were reviewed. Nodules' ultrasound/cytological characteristics were assessed. Variables studied: referral cause; referral pattern (hospital-specialist versus general-practitioner); number of nodules; age, thyroid function; nodule size, TIRADS classification, resistive index, Doppler pattern, Bethesda categorisation. Variables were compared between males and females referred for FNA. Significant variables were assessed with logistic regression.

RESULTS

Of the 272 patients, 215(79%) were women with a female:male referral ratio for FNA of 3.8:1. Non-parametric statistically significant differences (p < 0.05) were found between genders in: thyroid function, nodule size, referral pattern and referral cause. Nodule size and thyroid function tests became non-significant in logistic regression. Cause and referral pattern remained significantly associated with gender. Referral by a general-practitioner was associated with a 2.6-fold increase in odds of referring a female. Causes unrelated to the thyroid were associated with a 3.2-fold increase in odds of female reference.

CONCLUSIONS

A referral bias might be responsible for the higher rate of thyroid nodules in female patients, both due to referral by general practitioners and due to causes indirectly related to the thyroid gland.

Measurement properties of ThyPRO short-form (ThyPRO-39) for use in Chinese patients with benign thyroid diseases

PURPOSE

To evaluate the validity and reliability of a newly-translated Thyroid-specific Patient-Reported Outcome short-form (ThyPRO-39) instrument for ethnic-Chinese patients suffering from benign thyroid diseases.

METHODS

The translation and cross-cultural adaptation of the English ThyPRO-39 were performed using the double forward translation, reconciliation, single backward translation, and cognitive debriefing, followed by a panel review. Cross-sectional data of 308 patients with benign thyroid diseases were utilized for this psychometric evaluation of ThyPRO-39 instrument. Convergent validity between similar construct in the ThyPRO-39, SF-6D, and SF-12v2 was assessed using Spearman correlations. The internal construct validity was assessed by corrected item-total correlations. Sensitivity of the ThyPRO-39 domain scores was determined by performing known group comparisons by independent t test. The internal consistency reliability was assessed by Cronbach's alpha coefficient.

RESULTS

Significant floor effects were observed in 9 out of 13 domains of the ThyPRO-39. The hypothesized correlations between similar constructs in the ThyPRO-39 and the SF-12v2 and SF-6D were generally observed, supporting convergent validity. The internal construct validity was supported in most items, except eight items in six scales. Scale score of hyperthyroid symptoms of the ThyPRO-39 was significantly higher in the group with Graves' disease or hyperthyroid disease than the group without Graves' disease nor hyperthyroid disease. Scale scores of eye symptoms and impaired daily life were significantly higher in the incidental group than the non-incidental group. For six domains (hyperthyroid symptoms, hypothyroid symptoms, eye symptoms, tiredness, depressivity, and emotional susceptibility), Cronbach's alpha did not reach the recommended standard of 0.7.

CONCLUSIONS

This was the first psychometric study to translate and adapt the ThyPRO-39 instrument for non-Caucasian patients, and report its validity and reliability for use in Chinese patients with benign thyroid diseases. Given the low item-total correlations in eight items and low internal consistency reliability in respective scales of the ThyPRO-39, we suggest that the improvement of those eight items should produce a more valid and reliable ThyPRO-39 instrument.

Predicting 131I-avidity of metastases from differentiated thyroid cancer using 18F-FDG PET/CT in postoperative patients with elevated thyroglobulin

The quantitative relationship between iodine and glucose metabolism in metastases from differentiated thyroid cancer (DTC) remains unknown. Aim of the prospective study was to establish the value of ¹⁸F-FDG PET/CT in predicting ¹³¹I-avidity of metastases from DTC before the first radioiodine therapy. A total of 121 postoperative DTC patients with elevated stimulated serum thyroglobulin (ssTg) who underwent ¹³¹I adjuvant therapy or therapy after ¹⁸F-FDG PET/CT scan were enrolled. The Receiver operating characteristic curve was established to create an optimal cut-off point and evaluate the value of SUVmax for predicting ¹³¹I-avidity. In our study, the median SUVmax in ¹³¹I-nonavid metastatic target lesions was also significantly higher than that in ¹³¹I-avid metastatic target lesions (5.37 vs. 3.30; P = 0.000). At a cut-off value of 4.0 in SUVmax, the area under curve was 0.62 with the sensitivity, specificity, positive predictive value and negative predictive value of 75.3%, 56.7%, 76.1%, and 54.8%, respectively. These results suggest that ¹⁸F-FDG PET/CT may be of great value in identifying metastases in postoperative DTC patients with elevated ssTg before ¹³¹I administration, leading to an improved management of disease. ¹⁸F-FDG positive metastatic DTC with SUVmax of greater than 4.0 possesses higher probability of non-avidity to radioiodine.

Acquired resistance to BRAF inhibition induces epithelial-to-mesenchymal transition in BRAF (V600E) mutant thyroid cancer by c-Met-mediated AKT activation

Previously, the authors have identified that c-Met mediates reactivation of the PI3K/AKT pathway following BRAF inhibitor treatment in BRAF (V600E) mutant anaplastic thyroid cancer, thereby contributing to the acquired drug resistance. Therefore dual inhibition of BRAF and c-Met led to sustained treatment response, thereby maximizing the specific anti-tumor effect of targeted therapy. The present study goes one step further and aims to investigate the effect of acquired resistance of BRAF inhibitor on epithelial-to-mesenchymal transition (EMT) in BRAF mutant thyroid cancer cells and the effect of dual inhibition from combinatorial therapy. Two thyroid cancer cell lines, 8505C and BCPAP were selected and treated with BRAF inhibitor, PLX4032 and its effect on EMT were examined and compared. Further investigation was carried out in orthotopic xenograft mouse models. Unlike BCPAP cells, the BRAF inhibitor resistant 8505C cells showed increased expressions of EMT related markers such as vimentin, β-catenin, and CD44. The combinatorial treatment of PLX4032 and PHA665752, a c-Met inhibitor reversed EMT. Similar results were confirmed in vivo. c-Met-mediated reactivation of the PI3K/AKT pathway contributes to the drug resistance to PLX4032 in BRAF (V600E) mutant anaplastic thyroid cancer cells and further promotes tumor cell migration and invasion by upregulated EMT mechanism. Dual inhibition of BRAF and c-Met leads to reversal of EMT, suggesting a maximal therapeutic response.

Tertiary Care Experience of Sorafenib in the Treatment of Progressive Radioiodine-Refractory Differentiated Thyroid Carcinoma: A Korean Multicenter Study

BACKGROUND

Sorafenib, a multi-kinase inhibitor, is approved for the treatment of patients with radioactive iodine (RAI)-refractory differentiated thyroid cancer (DTC). This study evaluated the efficacy and safety of sorafenib in real-world clinical practice and compared the results to those of the DECISION trial. The clinical features associated with better clinical outcomes after sorafenib treatment were also evaluated.

METHODS

This multicenter, retrospective cohort study evaluated 98 patients with progressive RAI-refractory DTC who were treated with sorafenib in six tertiary hospitals in Korea. The primary objective was the progression-free survival (PFS) according to Response Evaluation Criteria In Solid Tumors v1.1. Overall survival, response rate (defined as the best objective response according to Response Evaluation Criteria In Solid Tumors v1.1), and safety were also evaluated.

RESULTS

The median PFS was 9.7 months; median overall survival was not reached during follow-up. Partial responses and stable disease were achieved in 25 (25%) and 64 (65%) patients, respectively. Stable disease of >6 months was achieved in 41 (42%) patients. Subgroup analyses identified several prognostic indicators of a better PFS: absence of disease-related symptoms (hazard ratio [HR] = 0.5; p = 0.041), lung-only metastasis (HR = 0.4; p = 0.048), a daily maintenance dose ≥600 mg (HR = 0.3; p = 0.005), and a thyroglobulin reduction ≥60% (HR = 0.4; p = 0.012). The mean daily dose of sorafenib was 666 ± 114 mg, and drug withdrawals due to adverse events (AEs) occurred in 13% of patients. AEs and serious AEs were reported in 93 (95%) and 40 (41%) patients, respectively. The most frequent AE was hand-foot skin reaction (76%).

CONCLUSIONS

The PFS of progressive RAI-refractory DTC patients treated with sorafenib was consistent with the findings of the DECISION trial. Disease-related symptoms, lung-only metastasis, a daily maintenance dose, and thyroglobulin reduction were significantly associated with PFS. These results suggest that sorafenib is an effective treatment option for patients with progressive RAI-refractory DTC.

Clinical characteristics and disease outcome of patients with non-medullary thyroid cancer and brain metastases

Brain metastases from non-medullary thyroid carcinoma (NMTC) are rare, with a reported frequency of ~1%, and patient survival time is <1 year after diagnosis. The optimal management of brain metastases in this setting continues to be debated. The aim of the present study was to evaluate a series of patients with brain metastases from NMTC attending a single tertiary medical center. The electronic database of Rabin Medical Center was reviewed for all patients with NMTC and distant metastases who were diagnosed and treated between 1970 and 2014. Those with brain metastases were identified and formed the study group. Data were collected from medical records comprising clinicopathological characteristics, time intervals for diagnosis and treatment, treatment modalities and outcome. Of the 172 patients with NMTC and distant metastases, 10 possessed brain metastases. These included 6 females and 4 males of median age 53.5 years (range, 18–81 years). All patients had lung metastases and 7 demonstrated bone metastases. The median interval between the diagnoses of NMTC and brain metastases was 40 months (range, 9–207 months). Of the 10 patients, 1 presented with brain metastases at primary diagnosis. Treatment of the brain metastases consisted of surgery, radiotherapy (external beam, stereotactic), and radioiodine, alone or in combination. A total of 2 patients received tyrosine kinase inhibitors. The median overall survival time from diagnosis of brain metastasis was 15 months. A total of 2 patients remained alive at the last follow-up (32 and 300 months, respectively). The present study demonstrated that brain metastases may occur in ≤6% of patients with NMTC and distant metastases. Brain metastases rarely present at diagnosis of NMTC and are associated with metastases in other distant sites. Systematic screening for brain metastases requires consideration in all patients with NMTC and distant metastases. Some patients show an indolent evolution with overall survival of >2 years, supporting an aggressive treatment approach.

Analysis of postoperative ultrasonography surveillance after total thyroidectomy in patients with papillary thyroid carcinoma: a multicenter study

Background In papillary thyroid carcinoma (PTC) patients, postoperative ultrasonography (US) surveillance is recommended at intervals of six or 12 months even though evidence is weak. Purpose To determine the optimal interval of postoperative US surveillance in patients after total thyroidectomy for the treatment of PTC using multicenter data. Material and Methods A total of 1400 patients from seven tertiary hospitals who underwent total thyroidectomy for treatment of PTC were included. Based on a retrospective review of clinical and pathologic results, multiple factors were analyzed according to recurrence/persistence or no recurrence/persistence. In recurrence/persistence group, the interval and number of follow-up US sessions in the initial detection of recurrence/persistence were investigated. Results Of the 1400 patients, 115 (8.2%) showed tumor recurrence/persistence on follow-up US. Of 115 recurrence/persistence cases, 89 (77.4%) were initially detected on US: nodal recurrence/persistence (n = 92), non-nodal recurrence/persistence (n = 22), and both (n = 1). Among the clinical and pathologic factors, only tumor size and N stage were significant predictors for recurrence/persistence. In the recurrence/persistence group, the mean interval and number of follow-up US sessions in the initial detection of recurrence/persistence was 22.3 ± 16.8 months and 2.2 ± 1.9, respectively. Approximately two-thirds of recurrence/persistence cases (76/115, 66.1%) were detected in follow-up US within two years after total thyroidectomy. Conclusion In PTC patients after total thyroidectomy, the optimal interval of the first US follow-up may be one to two years after thyroid surgery, and the appropriate number of postoperative US surveillance sessions within the first five years may be only one or two.

The Effects of Growth Inhibitory Peptide on Follicular Thyroid Cancer Cell Growth, Migration, and Invasion

Aims and background

Thyroid cancer is the most common endocrine neoplasm worldwide. Although differentiated thyroid cancers are associated with a favorable survival, the prognosis worsens dramatically for patients with distant metastasis. Metastases from follicular thyroid carcinoma (FTC) occur earlier and are more aggressive than those from papillary thyroid carcinoma. For FTC that is resistant to radioactive iodine, new treatments are urgently needed. Human alpha-fetoprotein (HAFP) is a tumor-associated fetal protein that has been demonstrated to regulate tumorigenesis. Growth inhibitory peptide (GIP), a synthetic 34-mer peptide isolated from the third domain of HAFP, has been shown to have antitumor growth ability in various human cancers. However, the effects of GIP in FTC have not yet been studied. The aim of this study was to investigate the antitumor ability of GIP in FTC.

Methods and study design

Using both PBS and GIP control peptide as a negative control, the antiproliferative activity of GIP in the WRO human FTC cell line was determined using a tetrazolium-based colorimetric assay. In addition, cell migration and invasion assays were used to measure tumor metastasis inhibition effects in vitro.

Results

GIP did not inhibit WRO cell proliferation in a time- or dose-dependent manner. However, in WRO cells treated with GIP for 4 days, migration was significantly inhibited at concentrations of 50 and 100 μM (33.3% and 19.5%, respectively; both P <0.05). Cell invasion was also significantly inhibited at 50 and 100 μM (67.1% and 39.0%, respectively; both P <0.05).

Conclusions

Although GIP failed to suppress FTC cell growth, it effectively interrupted both FTC cell migration and invasion abilities in vitro. Further validation in an animal model and elucidation of the underlying mechanisms will be required. GIP may potentially serve as an anti-FTC metastasis agent aiding current chemotherapy regimens.

Monitoring differentiated thyroid cancer patients with negative serum thyroglobulin

Aim: Serum antithyroglobulin antibody (TgAb) has been reported as a surrogate marker for differentiated thyroid cancer (DTC) in some conditions. We investigated changes in serum TgAb levels after stimulation with thyroid- stimulating hormone (TSH) and the clinical implications for monitoring DTC. Patients, methods: We retrospectively enrolled 53 DTC patients who had undergone total thyroidectomy and were negative for serum Tg and positive for TgAb. Patients underwent highdose radioactive iodine treatment, and serum TgAb was measured before (TgAbBAS) and after TSH stimulation (TgAbSTIM). TgAb was followed up 6 to 12 months later (TgAbF/U). The change in TgAb after TSH stimulation ΔTgAb- STIM) was calculated as a percentage of the baseline level. Patient disease status was classified into no residual disease (ND) and residual or recurred disease (RD) by follow-up imaging studies and pathologic data. The characteristics and diagnostic value of serum TgAb levels and ΔTgAbST|M were investigated with respect to disease status. Results: 38 patients were in the ND group and 15 were in the RD group. TgAbBAS, TgAbSTIM and TgAbF/U were significantly higher in the RD compared to the ND group (p = 0.0008, 0.0002, and < 0.0001, respectively). ΔTgAbSTIM was also significantly higher in the RD group (p = 0.0009). In the patients who presented with obviously high (> 50%) or low (< -50%) ΔTgAbSTIM, the proportions in the RD group were markedly different at 100% and 7%, respectively. ΔTgAbSTIM had significant diagnostic value for RD (p < 0.001). Conclusion: The change in serum TgAb level after TSH stimulation is different between the RD and ND groups, and thus, it may be used as a surrogate diagnostic marker for DTC when the serum Tg is negative and TgAb is positive.