Recombinant human thyrotropin-stimulated serum thyroglobulin combined with neck ultrasonography has the highest sensitivity in monitoring differentiated thyroid carcinoma

The history of thyroid ultrasound: Past, present, and future directions

The rapid evolution of ultrasound (US) technology has dramatically changed the medical field. Ideally suited for evaluation of anatomic disorders of the thyroid, coupled with its ease of use at the bedside, US has become an essential tool for Endocrinologists over the last 50 years. This noninvasive technology provides a sensitive and specific instrument for malignancy risk prediction of thyroid nodules, surveillance for recurrent thyroid cancer, and diagnosis of autoimmune thyroid disorders. While US has proven invaluable for such diagnostic purposes, its extensive use also has resulted in important negative consequences. This review will discuss the evolution of US equipment for the evaluation of thyroid disorders, its use in interventional procedures, and the unintended outcomes from the widespread adoption of this technology. Finally, this article will explore the potential future applications for US technology and its related advancements.

Differentiated thyroid carcinoma: what the nonspecialists needs to know

Differentiated thyroid carcinoma (DTC) accounts for most cases of thyroid cancer, and the heterogeneity of DTC requires that management decisions be taken by a multidisciplinary team involving endocrinologists, head and neck surgeons, nuclear medicine physicians, pathologists, radiologists, radiation oncologists, and medical oncologists. It is important for nonspecialists to recognize and refer patients with DTC who will benefit from a specialized approach. Recent advances in knowledge and changes in management of DTC call for the need to raise awareness on the part of these nonspecialist physicians, including general endocrinologists and medical oncologists at large. We provide an overview of diagnostic and therapeutic principles in DTC, especially those that bear direct implication on day-to-day management of these patients by generalists. Patients with DTC may be broadly categorized as having localized, locally persistent/recurrent, or metastatic disease. Current recommendations for DTC include a three-tiered system that classifies patients with localized disease into low, intermediate, or high risk of persistent or recurrent disease. Risk stratification should be performed at baseline and repeated on an ongoing basis, depending on clinical evolution. One of the overarching goals in the management of DTC is the need to personalize treatment by tailoring its modality and intensity according to ongoing prognostic stratification, evolving knowledge about the disease, and patient characteristics and preference. In metastatic disease that is refractory to radioactive iodine, thyroid tumors are being reclassified into molecular subtypes that better reflect their biological properties and for which molecular alterations can be targeted with specific agents.

Thyroid ultrasound and its ancillary techniques

Ultrasound (US) of the thyroid has been used as a diagnostic tool since the late 1960s. US is the most important imaging tool for diagnosing thyroid disease. In the majority of cases a correct diagnosis can already be made in synopsis of the sonographic together with clinical findings and basal thyroid hormone parameters. However, the characterization of thyroid nodules by US remains challenging. The introduction of Thyroid Imaging Reporting and Data Systems (TIRADSs) has improved diagnostic accuracy of thyroid cancer significantly. Newer techniques such as elastography, superb microvascular imaging (SMI), contrast enhanced ultrasound (CEUS) and multiparametric ultrasound (MPUS) expand diagnostic options and tools further. In addition, the use of artificial intelligence (AI) is a promising tool to improve and simplify diagnostics of thyroid nodules and there is evidence that AI can exceed the performance of humans. Combining different US techniques with the introduction of new software, the use of AI, FNB as well as molecular markers might pave the way for a completely new area of diagnostic accuracy in thyroid disease. Finally, interventional ultrasound using US-guided thermal ablation (TA) procedures are increasingly proposed as therapy options for benign as well as malignant thyroid diseases.

The role of 18 F-FDG-PET/CT in the management of differentiated thyroid cancer

INTRODUCTION

In previous literature, 18 F-FDG-PET/ CT imaging significantly impacted differentiated thyroid cancer (DTC) therapy. Low thyroglobulin (Tg) levels and negative Iodine-131 (131I) whole-body scan (WBS), along with negative 18 F-FDG-PET/ CT, suggested a lesser likelihood of active illness. Positive 18 F-FDG-PET/CT findings, however, were associated with a variety of signs of local recurrence and regional or distant metastases in patients with suspected WBS. We aim to evaluate the utility of 18 F-FDG-PET/CT in managing DTC patients with negative 131I post-therapy WBS and elevated Tg.

MATERIAL AND METHODS

We retrospectively reviewed 55 patients with DTC (76% papillary and 24% follicular). Patients underwent total thyroidectomy or several radioactive iodine (RAI) treatments or both. WBS was performed 5-7 days after RAI treatment. Inclusion criteria were elevated serum Tg, negative anti-Tg auto-antibodies (AbTg) during long-term follow-up, presence of 18F-FDG-PET/CT images, and negative or suspicious WBS.

RESULTS

54% of 18 F-FDG-PET/CTs detected at least one lesion, mainly, cervical lymph nodes (49.9%), mediastinal lymph nodes (40.4%), local recurrence (34%), and bone or tissue metastasis (36.2%). The three major sites of metastasis were lung, bone, and liver. 18 F-FDG-PET/CT identified recurrence or metastasis in 45% of patients with high serum Tg and negative WBS, modifying therapeutic management in half the patients for suitable treatment modality (surgery vs. tyrosine kinase inhibitor).

CONCLUSION

The findings redemonstrate that elevated Tg with negative or suspicious WBS necessitates 18 F-FDG-PET/CT for localization of recurrence. 18 F-FDG-PET/CT is useful in managing locally recurrent or metastatic DTC with high Tg levels. It influences treatment and accurately assesses disease severity.

Radioiodine therapy in advanced differentiated thyroid cancer: Resistance and overcoming strategy

Thyroid cancer is the most prevalent endocrine tumor and its incidence is fast-growing worldwide in recent years. Differentiated thyroid cancer (DTC) is the most common pathological subtype which is typically curable with surgery and Radioactive iodine (RAI) therapy (approximately 85%). Radioactive iodine is the first-line treatment for patients with metastatic Papillary Thyroid Cancer (PTC). However, 60% of patients with aggressive metastasis DTC developed resistance to RAI treatment and had a poor overall prognosis. The molecular mechanisms of RAI resistance include gene mutation and fusion, failure to transport RAI into the DTC cells, and interference with the tumor microenvironment (TME). However, it is unclear whether the above are the main drivers of the inability of patients with DTC to benefit from iodine therapy. With the development of new biological technologies, strategies that bolster RAI function include TKI-targeted therapy, DTC cell redifferentiation, and improved drug delivery via extracellular vesicles (EVs) have emerged. Despite some promising data and early success, overall survival was not prolonged in the majority of patients, and the disease continued to progress. It is still necessary to understand the genetic landscape and signaling pathways leading to iodine resistance and enhance the effectiveness and safety of the RAI sensitization approach. This review will summarize the mechanisms of RAI resistance, predictive biomarkers of RAI resistance, and the current RAI sensitization strategies.

Current Controversies in Low-Risk Differentiated Thyroid Cancer: Reducing Overtreatment in an Era of Overdiagnosis

CONTEXT

Low-risk differentiated thyroid cancer (DTC) is overdiagnosed, but true incidence has increased as well. Owing to its excellent prognosis with low morbidity and mortality, balancing treatment risks with risks of disease progression can be challenging, leading to several areas of controversy.

EVIDENCE ACQUISITION

This mini-review is an overview of controversies and difficult decisions around the management of all stages of low-risk DTC, from diagnosis through treatment and follow-up. In particular, overdiagnosis, active surveillance vs surgery, extent of surgery, radioactive iodine (RAI) treatment, thyrotropin suppression, and postoperative surveillance are discussed.

EVIDENCE SYNTHESIS

Recommendations regarding the diagnosis of DTC, the extent of treatment for low-risk DTC patients, and the intensity of posttreatment follow-up have all changed substantially in the past decade. While overdiagnosis remains a problem, there has been a true increase in incidence as well. Treatment options range from active surveillance of small tumors to total thyroidectomy followed by RAI in select cases. Recommendations for long-term surveillance frequency and duration are similarly broad.

CONCLUSION

Clinicians and patients must approach each case in a personalized and nuanced fashion to select the appropriate extent of treatment on an individual basis. In areas of evidential equipoise, data regarding patient-centered outcomes may help guide decision-making.

Active surveillance in differentiated thyroid cancer: a strategy applicable to all treatment categories response

Currently, the differentiated thyroid cancer (DTC) management is shifted toward a tailored approach based on the estimated risks of recurrence and disease-specific mortality. While the current recommendations on the management of metastatic and progressive DTC are clear and unambiguous, the management of slowly progressive or indeterminate disease varies according to different centers and different physicians. In this context, active surveillance (AS) becomes the main tool for clinicians, allowing them to plan a personalized therapeutic strategy, based on the risk of an unfavorable prognosis, and to avoid unnecessary treatment. This review analyzes the main possible scenarios in treated DTC patients who could take advantage of AS.

Thyroglobulin Assay Interferences: Clinical Usefulness of Mass-Spectrometry Methods

Context

Thyroglobulin autoantibodies (TgAbs) affect thyroglobulin immunometric assays (TgIMAs), causing falsely low results. Conversely, heterophilic antibodies (HAs) may cause falsely elevated results. Thyroglobulin (Tg) measurements by mass spectrometry (MS) resist antibody interference. The most effective use of TgIMA/TgMS in the evaluation of Tg remains unclear.

Objective

The objective of this work was to study the usefulness of TgMS vs TgIMA in the presence of Tg measurement interference by HA and TgAb.

Methods

In 163 thyroid cancer patients, Tg was postoperatively measured by TgIMA and TgMS. When TgIMA was elevated and TgMS undetectable, HA was assessed by serial dilution and pretreatment with HA blocking reagent. TgIMA and TgMS were compared in TgAb-positive patients with well-characterized clinical status.

Results

6 out of 45 cases with TgIMA >1 ng/mL had undetectable TgMS. HA interference was confirmed by serial dilution and HA blocking reagent addition. In TgAb-positive cases, TgIMA and TgMS were highly correlated (R² = 0.86). In patients with structural disease and TgAb, TgIMA and TgMS were detectable in 6/19 patients, and 9/19 cases, respectively. The TgMS concentration range in the 3 discrepant cases ranged from 0.5 to 2.0 ng/mL. Hence, the presence of TgAb was associated with inappropriately reduced Tg concentrations with both TgIMA and TgMS.

Conclusion

HA cause falsely elevated TgIMA with undetectable TgMS with significant frequency. TgMS can be used to rule out HA interference. Albeit resistant to TgAb in vitro, TgMS detects little Tg in patients with TgAb and structural disease. Hence, TgAb may reduce Tg concentrations in vivo. The implication is that no assay design may be able to overcome this problem. TgMS may not detect structural disease in TgAb-positive patients.

Paediatric differentiated thyroid carcinoma: a UK National Clinical Practice Consensus Guideline

This guideline is written as a reference document for clinicians presented with the challenge of managing paediatric patients with differentiated thyroid carcinoma up to the age of 19 years. Care of paediatric patients with differentiated thyroid carcinoma differs in key aspects from that of adults, and there have been several recent developments in the care pathways for this condition; this guideline has sought to identify and attend to these areas. It addresses the presentation, clinical assessment, diagnosis, management (both surgical and medical), genetic counselling, follow-up and prognosis of affected patients. The guideline development group formed of a multi-disciplinary panel of sub-speciality experts carried out a systematic primary literature review and Delphi Consensus exercise. The guideline was developed in accordance with The Appraisal of Guidelines Research and Evaluation Instrument II criteria, with input from stakeholders including charities and patient groups. Based on scientific evidence and expert opinion, 58 recommendations have been collected to produce a clear, pragmatic set of management guidelines. It is intended as an evidence base for future optimal management and to improve the quality of clinical care of paediatric patients with differentiated thyroid carcinoma.

Long-term follow-up ultrasonography surveillance in a large cohort of patients with papillary thyroid carcinoma

OBJECTIVE

This study aimed to investigate the predictive factors as well as the time and age course of recurrence/persistence in a large cohort of postoperative patients with papillary thyroid carcinoma (PTC) based on the long-term ultrasonography (US) follow-up data.

METHODS

Between January 2007 and December 2016, 3106 patients underwent surgery for PTC and at least two postoperative US follow-up examination over more than three years. Tumor recurrence/persistence was confirmed based on the follow-up US data and histopathological results. Univariate and multivariate analyses were performed to evaluate the predictive factors of tumor recurrence/persistence. Kaplan-Meier survival analysis was used to evaluate the recurrence-/persistence-free survival curve based on the US results.

RESULTS

A total of 321(10.3%) patients developed tumor recurrence/persistence during 54.3 months of mean follow-up (range 36-135 months), including 268(83.5%) cases of lymph node recurrence/persistence, 37 (11.5%) cases of non-lymph node recurrence/persistence, and 16(5%) cases of both types. Recurrence/persistence was observed using US examination at a mean interval of 23.6 ± 21.6 months (range 1-135 months) after surgery and peak incidence was observed 1-2 years after initial treatment. Younger (20-30 years old) and older (70-80 years old) patients had a higher proportion of tumor recurrence/persistence. Multifocality, advanced T and advanced N stages were independent risk factors of tumor recurrence/persistence.

CONCLUSION

Tumor recurrence/persistence of PTC usually occurs during the early postoperative period. For patients with multifocal cancer, advanced T and N stage, the US surveillance examination should be cautiously performed, especially in younger and older patients.

Thyroglobulin and thyroglobulin antibodies: assay-dependent management consequences in patients with differentiated thyroid carcinoma

OBJECTIVES

International guidelines recommend fixed cut-off values for thyroglobulin (Tg). These cut-offs do not take potential assay differences into account. This study aimed to evaluate if different assays for Tg and Tg antibodies (TgAb) affect management guidance for differentiated thyroid cancer (DTC) patients.

METHODS

In 793 samples derived from 413 patients with DTC, Tg and TgAb were simultaneously measured with two immunometric assays: Immulite 2000XPi and Kryptor compact plus. In addition, a qualitative measurement for TgAb interference (recovery test) was performed on the Kryptor compact plus platform. The extent to which different assays lead to different classifications of response to therapy was evaluated when applying the current cut-offs for Tg.

RESULTS

Mean Tg concentrations were 37.4% lower with Kryptor as compared with Immulite. Applying guideline based cut-off values for Tg, 33 (4.7%) samples had a Tg-on concentration ≥1.0 μg/L with Immulite and <1.0 μg/L with Kryptor. Of the samples tested as TgAb+ with at least one assay (n=125), 68 (54.4%) samples showed discrepancy in TgAb status. Differences between Immulite and Kryptor measurements resulted in a change in the response to therapy classification in 94 (12.0%) measurements derived from 67 (16.2%) individual patients.

CONCLUSIONS

A substantial portion of DTC patients were classified differently dependent on which Tg and TgAb assays are used, when applying the cut-off values as defined in clinical guidelines. Such differences can significantly affect clinical management. In the context of large between-method variation, the recommended Tg cut-offs in guidelines should be used with wisdom rather than as fixed cut-offs.

Imaging of Treated Thyroid and Parathyroid Disease

The thyroid and parathyroid glands are endocrine structures located in the visceral space of the infrahyoid neck. Imaging plays a critical role in the evaluation of patients with thyroid cancer, both in the pre and posttreatment setting. Disorders of thyroid function, that is, hyperthyroidism and hypothyroidism, are also fairly common, although imaging utilization is less frequent with these conditions. Parathyroid dysfunction results in disordered calcium metabolism. Imaging is frequently applied in the preoperative assessment of these patients undergoing parathyroidectomy; however, routine imaging in the postoperative setting is uncommon. Parathyroid carcinoma is rare; however, imaging may be used in the pre and posttreatment setting.

Optimization of follow-up in patients with papillary thyroid cancer who show no evidence of disease 9-12 months after treatment

BACKGROUND

Papillary thyroid cancer (PTC) has an excellent prognosis, and recurrence is rare in patients with no evidence of disease (NED) after initial treatment. Despite this, several guidelines recommend long and costly follow-up, with limited evidence of improved patient outcomes. This study aims to examine the value of follow-up in patients with NED after treatment for PTC, by determining the rate of recurrence, recurrence-associated morbidity, and death, and whether any recurrence was diagnosed through the follow-up programme.

METHODS

Patients operated for PTC at Lund University Hospital between January 2004 and December 2016 were eligible. Patients with T1a N0/NX were excluded as well as patients with any other thyroid malignancy. Data were collected retrospectively by searching the patients' medical records. NED was defined as thyroglobulin less than 1 ng/ml, thyroglobulin antibodies less than 20 kIU/l, and negative imaging. Biochemical recurrence was defined as thyroglobulin greater than 1 ng/ml, and/or thyroglobulin antibodies greater than 20 kIU/l. Structural recurrence was defined as a strong suspicion of recurrence on imaging and/or histological proof of recurrence.

RESULTS

Out of a cohort of 187 patients, there were 90 patients with NED who were followed for a median of 6.3 years. Three patients had biochemical recurrence; none of them had symptoms, nor were they treated for their recurrence. Three had structural recurrence; all were above 75 years old and only one was diagnosed through the follow-up programme. No patient died of PTC; five patients died during the follow-up.

CONCLUSION

Follow-up as it is designed today cannot identify recurrences accurately and seems to be of questionable benefit in younger patients with NED after treatment for PTC.

Histology is more ιmportant than persistent anti-Tg antibodies for progression of differentiated thyroid cancer

CONTEXT

Anti-thyroglobulin antibodies (anti-Tg), present in 20%-25% of differentiated thyroid cancer (DTC) patients, interfere with thyroglobulin measurements posing a challenge in the follow-up.

OBJECTIVES

The aim of this study was to identify clinical-histological factors that may affect anti-Tg persistence and disease outcome in DTC with positive anti-Tg.

METHODS

We retrospectively studied 234 DTC patients, with positive anti-Tg at diagnosis (females: 82.1%, age at diagnosis: 46.0 ± 14.4 yrs, median follow-up: 5 yrs (1.5-32 yrs). 221/234 (94.4%) received radioiodine (RAI) ablation. Patients were divided into two subgroups: those whose anti-Tg became undetectable (anti-Tg-NEG) and those whose anti-Tg remained positive (anti-Tg-POS) at the end of the follow-up period.

RESULTS

Anti-Tg-POS patients (n = 80, 34.2%) compared to anti-Tg-NEG (n = 154, 65.8%) had more frequently lymph node infiltration (36.3% vs 20.1%, P = .01), extrathyroidal extension (ETE, 35.0% vs 22.1%, P = .04), poorly differentiated DTC and increased tumour size (P ≤ .004). They received higher total RAI dose (P < .001). In most cases, additional RAI administration and/or additional surgeries did not lead to anti-Tg elimination. These had more frequently structural disease persistence/progression compared to anti-Tg-NEG (remission: 78.8% vs 95.5%, persistence: 13.8% vs 3.9%, progression: 7.5% vs 0.6%, P < .001). In Kaplan-Meier analysis, the probability of disease progression was higher in anti-Tg-POS. In Cox proportional hazard analysis, the predictors of disease progression were size (P = .002) and ETE (P = .006).

CONCLUSIONS

Worse histological features are more frequent in patients with anti-Tg persistence during follow-up. Further additional RAI administration and/or surgeries do not affect anti-Tg elimination in most cases. Anti-Tg persistence correlates with structural persistence although tumour size and extrathyroidal extension are the main predictors of disease progression.

2020 Imaging Guidelines for Thyroid Nodules and Differentiated Thyroid Cancer: Korean Society of Thyroid Radiology

Imaging plays a key role in the diagnosis and characterization of thyroid diseases, and the information provided by imaging studies is essential for management planning. A referral guideline for imaging studies may help physicians make reasonable decisions and minimize the number of unnecessary examinations. The Korean Society of Thyroid Radiology (KSThR) developed imaging guidelines for thyroid nodules and differentiated thyroid cancer using an adaptation process through a collaboration between the National Evidence-based Healthcare Collaborating Agency and the working group of KSThR, which is composed of radiologists specializing in thyroid imaging. When evidence is either insufficient or equivocal, expert opinion may supplement the available evidence for recommending imaging. Therefore, we suggest rating the appropriateness of imaging for specific clinical situations in this guideline.

Can shear wave elastography determine remnant thyroid tissue in the early postoperative period in patients with differentiated thyroid carcinoma?

PURPOSE

This study aims to investigate the usability of ultrasonography (US) and shear wave elastography (SWE) in detecting remnant thyroid tissue (RTT) within the first three postoperative months in patients who underwent total thyroidectomy (TT) for differentiated thyroid cancer (DTC) and who were scheduled for radioiodine (RAI) ablation therapy.

METHODS

Sixty-nine patients who underwent a TT operation due to DTC were included in the study. The participant's thyroid surgical bed was first evaluated by thyroid scintigraphy and then by greyscale US and SWE to investigate RTT. The participants were divided into two groups, those with and those without RTT. SWE quantitative data were compared between the two groups. Receiver operating characteristic (ROC) curve analysis was performed to determine the best cut-off values for stiffness and velocity in distinguishing RTT.

RESULTS

A total of 149 regions were analysed in 69 participants (43 females, 26 males). The average time elapsed after the operation was 65.2 ± 24.1 days. RTT was determined by scintigraphy and US-SWE in 38 (55%) patients. The stiffness and velocity values were significantly higher in the group with RTT than in the group without RTT. To distinguish RTT from the thyroid bed, the best cut-off values for stiffness and velocity were 15.7 kPa and 2.12 m/s, respectively.

CONCLUSIONS

US with SWE can detect RTT in the early postoperative period in patients who have undergone TT due to DTC and who are scheduled for RAI treatment. The use of US and SWE will be particularly beneficial in patients with RTT but who have false-negative Tg levels and RTT that is not I-131 avid.

Physician Confidence in Neck Ultrasonography for Surveillance of Differentiated Thyroid Cancer Recurrence

IMPORTANCE

Neck ultrasonography, a mainstay of long-term surveillance for recurrence of differentiated thyroid cancer (DTC), is routinely used by endocrinologists, general surgeons, and otolaryngologists; however, physician confidence in their ability to use ultrasonography to identify lymph nodes suggestive of cancer recurrence remains unknown.

OBJECTIVE

To evaluate physicians' posttreatment surveillance practices for DTC recurrence, specifically their use of and confidence in ultrasonography.

DESIGN, SETTING, AND PARTICIPANTS

Cross-sectional study of 448 physicians in private and academic hospitals who completed a survey on DTC posttreatment practices from October 2018 to August 2019 (response rate, 69%) and self-reported involvement in long-term surveillance for thyroid cancer recurrence. Physicians were identified by patients affiliated with the Surveillance, Epidemiology, and End Results Program registries in Georgia State and Los Angeles County. Of the respondents, 320 physicians who reported involvement with DTC surveillance were included in the analysis.

MAIN OUTCOMES AND MEASURES

Physician-reported long-term surveillance practices for DTC, including frequency of use and level of confidence in ultrasonography for detecting lymph nodes suggestive of cancer recurrence.

RESULTS

In the cohort of 320 physicians who reported involvement with DTC surveillance, 186 (60%) had been in practice for 10 years to less than 30 years; 209 (68%) were White; and 212 (66%) were men. The physicians included 170 (56%) endocrinologists, 67 (21%) general surgeons, and 75 (23%) otolaryngologists. Just 84 (27%) physicians reported personally performing bedside ultrasonography. Only 57 (20%) had high confidence (rated quite or extremely confident) in their ability to use bedside ultrasonography to identify lymph nodes suggestive of recurrence; 94 (33%) did not report high confidence in either their ability or a radiologist's ability to use ultrasonography to detect recurrence. Higher confidence in ultrasonography was associated with the general surgery subspecialty (odds ratio [OR], 5.7; 95% CI, 2.2-14.4; reference endocrinology) and with treating a higher number of patients per year (>50 patients: OR, 14.4; 95% CI, 4.4-47.4; 31-50 patients: OR, 8.4; 95% CI, 2.6-26.7; 11-30 patients: OR, 4.3; 95% CI, 1.5-12.1; reference 0-10 patients).

CONCLUSIONS AND RELEVANCE

Given the importance of neck ultrasonography in long-term surveillance for thyroid cancer, these findings of physicians' low confidence in their own ability and that of radiologists to use ultrasonography to detect recurrence point to a major obstacle to standardizing long-term DTC surveillance practices.

Pediatric differentiated thyroid carcinoma: An update from the APSA Cancer Committee

BACKGROUND

Differentiated thyroid carcinomas (DTCs) are rare in young children but represent almost 10% of all malignancies diagnosed in older adolescents.

METHODS

This article reviews the recent literature describing surgical therapeutic approaches to pediatric DTC, associated complications, and long-term recurrence and survival outcomes.

RESULTS

Similar to adult thyroid cancers, pediatric DTCs are more common in females and are associated with thyroid nodules, family history of thyroid cancer, radiation exposure, iodine deficiency, autoimmune thyroid disease, and genetic syndromes. Management of thyroid cancers in children involves ultrasound imaging, fine needle aspiration, and surgical resection with treatment decisions based on clinical and radiological features, cytology and risk assessment.

CONCLUSIONS

Total thyroidectomy and compartment based resection of clinically involved lymph node basins form the cornerstone of treatment of DTC. There is an evolving literature regarding the use of molecular genetics to inform treatment strategies and the use of targeted therapies to treat iodine refractory and surgically unresectable progressive disease.

TYPE OF STUDY

Summary review.

LEVEL OF EVIDENCE

This is a review article of previously published Level 1-5 articles that includes expert opinion (Level 5).

Associations of BRAF V600E, clinical pathology and imaging factors with the recurrence rate of papillary thyroid microcarcinoma

In the present study, the recurrence rate of papillary thyroid microcarcinoma (PTMC) was assessed by analyzing postoperative follow-up data of affected patients and its associations with BRAF V600E, clinical pathology and imaging factors were explored. A total of 506 patients with PTMC were selected who underwent surgery from January 2014 to March 2016. The maximal diameter of thyroid nodules was ≤1 cm and all patients who underwent BRAF V600E testing and evaluation for lymph node metastasis. Postoperatively, each patient was regularly followed up to detect recurrence. Categorical variables were comparatively analyzed using univariate Cox linear regression analysis to screen for protective and adverse factors influencing recurrence of PTMC. A stepwise Cox proportional hazards regression model analysis was performed to explore risk factors affecting recurrence. Among the 506 patients, 477 were followed up, 29 were lost to follow-up and 26 patients experienced recurrence. The 5-year recurrent rate of PTMC was 5.45%. The univariate Cox regression analysis indicated that PTMC recurrence was influenced by BRAF V600E, sex, multifocality, capsular invasion and lateral cervical lymph node metastasis (P<0.05), but not by age, tumor location on the thyroid, size, single central lymph node metastasis, distant metastasis and operative approach (P>0.05). The significant factors associated with recurrent PTMC were subjected to stepwise multivariate Cox proportional hazards regression model analysis and the results indicated that BRAF V600E, sex, multifocality and lateral cervical lymph node metastasis were independent factors influencing recurrence in patients with PTMC, with a statistically significant difference (P<0.05). In conclusion, BRAF V600E, sex, multifocality and lateral cervical lymph node metastasis are independent risk factors for recurrent PTMC.

Ultrasonography surveillance in papillary thyroid carcinoma patients after total thyroidectomy according to dynamic risk stratification

PURPOSE

To investigate the role of neck US surveillance in patients with papillary thyroid carcinoma (PTC) after total thyroidectomy according to dynamic risk stratification (DRS) based on response to initial therapy.

METHODS

This retrospective study included 812 patients with PTC who underwent total thyroidectomy with prophylactic central neck dissection from January 2003 through February 2007. The relative risk of recurrence/persistence according to DRS was evaluated with the multivariable Cox regression proportional hazard model.

RESULTS

There were 132 men and 680 women. The mean age at surgery was 45.2 years. Postoperative US was used for DRS. According to DRS, 676 patients had excellent response, 78 indeterminate response, 40 biochemical incomplete response, and 18 structural incomplete response to initial therapy. Neck US was performed during follow-up and detected locoregional recurrences in 21 patients (2.6%): 12 with excellent response, 2 with biochemical incomplete response, and 7 with structural incomplete response according to DRS. Only 1 patient (0.1%) with excellent response had a locoregional recurrence that exceeded 8 mm in its shortest diameter, which is the size cut-off for diagnostic US fine-needle aspiration in suspicious lymph nodes. This patient did not develop biochemical abnormalities during follow-up.

CONCLUSIONS

Postoperative neck US surveillance after total thyroidectomy with prophylactic central neck dissection is not essential in PTC patients who show excellent response to initial therapy. Future studies are needed to verify the role of US surveillance in patients who receive variable degrees of treatments.

Bioinformatic Identification of a Breast-Specific Transcript Profile

PURPOSE

To identify a breast-specific transcript profile for the first time, and present an updated bioinformatics strategy for searching tissue-specific transcripts and predicting their significance in cancer.

EXPERIMENTAL DESIGN

The RNA-seq data of 49 311 transcripts in 88 human tissues from the GTEx, the Illumina Body Map, and the RIKEN FANTOM5 project are integrated to screen breast-specific transcripts. Gene Expression Profiling Interactive Analysis, TGCA, and Kaplan-Meier Plotter are used to examine their expression in cancer tissues and values for prognosis prediction.

RESULTS

Only 96 transcripts in human genome are breast-specific for women. Among them, ankyrin repeat domain 30A (ANKRD30A) and long intergenic non-protein coding RNA 993 (LINC00993) are further analyzed. The two transcripts are also breast-specific in 33 types of common female cancer and are often dysregulated in breast cancer tissues. Their expression is higher in the luminal breast cancer while significantly downregulated in triple-negative breast cancer. Moreover, the high expression levels of ANKRD30A and LINC0993 in breast cancer tissues indicate a better prognosis of patients with breast cancer.

CONCLUSIONS AND CLINICAL RELEVANCE

Breast-specific transcripts in human genome are rare and poorly understood currently. The data indicate that these breast-specific biomarkers are promising candidates for screening early cancer, assessing treatment response, monitoring recurrence, identifying metastatic tumor origin, and serving as potential targets for immunotherapy.

Response to Therapy Assessment in Intermediate-Risk Thyroid Cancer Patients: Is Thyroglobulin Stimulation Required?

Introduction: The 2015 American Thyroid Association (ATA) guidelines recommend response to therapy (RTT) assessment 1-2 years after initial treatment in differentiated thyroid cancer (DTC) patients to guide thyrotropin (TSH) goals and long-term follow-up. We hypothesized that data collected during the first 2 years of follow-up may be sufficient to determine RTT without thyroglobulin (Tg) stimulation. Materials and Methods: Patients treated with total thyroidectomy and radioiodine for intermediate-risk DTC, followed for >2 years, and had sufficient follow-up data were included. Data on Tg, ultrasound, scans, and long-term outcomes were collected. Results: One-hundred twenty patients met inclusion criteria, with 68% women and mean age 55 ± 15 years. Intermediate risk was due to lymph-node involvement (72%), extrathyroidal extension (51%), vascular invasion (12%), and high-risk histology (9%). At the end of follow-up of 7 ± 4 years, 26% had persistent disease (14% biochemical, 12% structural). According to the ATA RTT system (using stimulated-Tg), 56% had excellent RTT, of whom only 2% had disease at the end of follow-up. In the "nonstimulated" system (which includes basal Tg, post-¹³¹I therapy whole-body scan (TxWBS) for assessment of residual lymph-node metastases after surgery, and structural imaging studies), 57% had excellent response, of whom none had disease at the end of follow-up. Only eight patients (7%) were classified differently due to recombinant human thyrotropin stimulation (as either excellent or indeterminate response), with no difference in predictive value, with a receiver-operator characteristic area under the curve of 0.903 with Tg-stimulation and of 0.918 without. Conclusions: In patients with no evidence of disease during the first 2 years of follow-up, the addition of stimulated-Tg adds little prognostic information. We suggest the use of excellent RTT based on basal Tg together with TxWBS and structural imaging studies.

I-131 Postablation SPECT/CT Predicts Relapse of Papillary Thyroid Carcinoma more Accurately than Whole Body Scan

BACKGROUND/AIM

The aim of the study was to prospectively compare I-131 postablation Whole Body scan (WBS) and Single Photon Emission Computerized Tomography/Computerized Tomography (SPECT/CT) scan on thyroid cancer patients.

PATIENTS AND METHODS

Overall, 58 patients with papillary thyroid carcinoma were submitted to total thyroidectomy and I-131 remnant ablation. Post-ablation WBS and SPECT/CT scans performed on the same day were compared. Results of SPECT/CT were confirmed by neck and upper mediastinum ultrasound scan and on specific cases by a fully diagnostic CT scan, other tests and definitive histology acting as the gold standard. A total of 36/58 patients were followed-up for 5 years to detect relapse.

RESULTS

Mac Nemar Chi square and Fisher's exact tests disclosed statistically significant differences between WBS and SPECT/CT scan, concerning cervical lymphadenopathy detection (p=0.031) and relapse prediction by NM stage (p=0.033), respectively; SPECT/CT was more accurate in both comparisons.

CONCLUSION

In papillary thyroid carcinoma I-131 post-ablation SPECT/CT scan detects cervical lymphadenopathy and predicts relapse by NM stage more accurately than WBS.

Less than 2% of the Low- and Intermediate-Risk Differentiated Thyroid Cancers Show Distant Metastases at Post-Ablation Whole-Body Scan

BACKGROUND

Recently, there has been a trend to reduce the use of radioiodine remnant ablation (RRA) in patients with low-risk (LR) and intermediate-risk (IR) differentiated thyroid cancer (DTC).

OBJECTIVES

The aim of this paper was to evaluate the diagnostic role of whole-body scan (ptWBS) performed after RRA in LR and IR DTC patients.

METHODS

We analyzed 545 DTC patients treated with total thyroidectomy and RRA in hypothyroidism followed by a ptWBS. Neck ultrasound (US) and serum thyroglobulin measurement were performed. According to the American Thyroid Association guidelines, patients were classified as LR (n = 345) and IR (n = 200).

RESULTS

In addition to the thyroid remnant, the ptWBS showed the presence of further areas of ¹³¹I uptake in 16/545 (2.9%) cases. ptWBS showed laterocervical lymph node metastases in 11/16 patients (10/11 were also detected by US), mediastinal uptake in 1/16, lung metastases in 3/16, and bone metastases in 1/16. Only 6/545 (1.1%) metastases were detected by ptWBS alone. After 7.8 years, 8/16 patients were free of disease, and 8 had persistent disease: 4 "biochemical" and 4 "structural." Remission was achieved in 3 cases after one single ¹³¹I course, in 1 case after surgery, and in the last 4 cases after several ¹³¹I courses.

CONCLUSIONS

The ptWBS diagnostic role was clinically relevant for the therapeutic strategies of our patients only in 1.1% of the cases. The cost-effectiveness of performing RRA and ptWBS in all LR and IR patients to find 1-2% of the cases with distant metastases remains controversial.

Neck Dissection in the Surgical Treatment of Thyroid Cancer

The incidence of thyroid cancer is increasing, largely attributable to overdetection related to prevalent diagnostic and radiologic imaging modalities. Papillary thyroid cancer remains the most common thyroid malignancy. It has a high tendency for regional metastasis to the cervical lymph nodes. The optimal management of the neck in patients with thyroid carcinoma has long been an important topic of debate. This article addresses central and lateral neck dissection, providing a simplified guide to the most up-to-date and evidence-based practices.

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.

Neck Ultrasound in Patients with Follicular Thyroid Carcinoma

There are limited data on the role of neck ultrasound (US) in the surveillance of patients with follicular thyroid cancer (FTC). Here, we analyze the likelihood of US to find structural disease in patients with FTC and evaluate if initial American Thyroid Association (ATA) risk stratification and the response to therapy categories [the latter based on thyroglobulin (Tg) levels] modify that likelihood. We conducted a retrospective cohort study of 32 patients with FTC in our institution. We included all patients with well-differentiated FTC who underwent total thyroidectomy and radioactive iodine (RAI) treatment without neck structural disease at the time of RAI and with Tg and US at least 6 months after RAI. After a median follow-up of 4.3 years, two patients (6.3%) had structural disease by US. None of the 18 patients with initial ATA low-risk disease had structural disease by US in contrast to higher, but not significant, frequency of 18.2% (2/11) in patients with initial ATA high-risk disease (p = 0.14). Based on Tg levels, 24/32 patients had excellent response to therapy and 8/32 had biochemical incomplete/indeterminate response. None of the patients with excellent response had structural disease by US versus 2/8 (25%) patients with biochemical incomplete/indeterminate response all of whom had other sites of structural disease (p = 0.054). Our findings suggest that neck US in FTC is unlikely to find structural disease with initial low-risk ATA or excellent response to therapy but can detect structural disease in some patients with initial ATA high-risk or incomplete/indeterminate responses to therapy.

Low or Undetectable Basal Thyroglobulin Levels Obviate the Need for Neck Ultrasound in Differentiated Thyroid Cancer Patients After Total Thyroidectomy and 131I Ablation

BACKGROUND

Neck ultrasound (NUS) is currently seen as a main component of follow-up of differentiated thyroid cancer (DTC) and is usually performed regardless of non-stimulated thyroglobulin (Tg) levels. The aim of this study was to determine whether there is a clinical benefit from such a routine NUS in DTC patients.

METHODS

A retrospective database study was conducted of 3176 cervical ultrasound exams performed in 773 patients between June 15, 1996, and July 1, 2012. The accuracy of ultrasound results was assessed based on the results of further diagnostic and/or therapeutic procedures within six months of a particular ultrasound.

RESULTS

A total of 2199 NUS exams were classified as true negative, 216 as true positive, 692 as false positive in 339 (43.9%) individual patients, 170 of whom were low risk, and 69 as false negative. Thus, overall sensitivity, specificity, positive predictive value, negative predictive value, and accuracy [confidence interval] were 75.8% [70.1-81.5%], 76.1% [74.3-77.8%], 23.8% [18.1-29.5%], 97.0 [96.2-97.7%], and 76.0% [74.3-77.7%], respectively. No significant differences were found between low- and high-risk patients. There were no significant differences between patients with an undetectable and a low detectable (<1 μg/L) Tg level. However, these two groups both showed significantly lower positive predictive value and higher negative predictive value than patients with a Tg ≥1 μg/L. From January 2007 onwards, true-positive and false-negative neck ultrasounds were no longer observed in patients with Tg <1 μg/L.

CONCLUSION

After total thyroidectomy and ¹³¹I ablation, neck ultrasound should be reserved only for anti-Tg antibody negative patients with a Tg level of ≥1 μg/L.

Appropriate Frequency and Interval of Neck Ultrasonography Surveillance during the First 10 Years after Total Thyroidectomy in Patients with Papillary Thyroid Carcinoma

BACKGROUND

No previous study has employed the frequency and interval of follow-up ultrasonography (US) during the first 10 years after total thyroidectomy in patients with papillary thyroid carcinoma (PTC). The aim of this study was to determine the appropriate frequency and interval of follow-up US during the first 10 years in patients who have undergone total thyroidectomy for PTC.

METHODS

Two hundred seventy-two patients underwent total thyroidectomy for PTC at our institution from January 2006 to December 2007. Nineteen patients were excluded because of lack of US follow-up data for the neck. Follow-up US was performed by one of two radiologists in all patients. Tumor recurrence/persistence was confirmed by histopathology.

RESULTS

The mean interval between surgery and the final follow-up US examination was 79.0 months, and the mean number of follow-up US sessions was 5.9 in the 253 evaluable patients. Eleven patients (4.3%) developed tumor recurrence/persistence, which was detected on follow-up US within 5 years after total thyroidectomy in all cases. T and N stages were independently associated with tumor recurrence/persistence. The interval between surgery and first suspicion of tumor recurrence/persistence on follow-up US was ≤12 months in six patients and 20, 35, 41, 53, and 60 months in the remaining five patients.

CONCLUSION

For detection of tumor recurrence/persistence after total thyroidectomy in patients with PTC, one or two sessions of follow-up US during the first 2 years, depending on T and N stages and one session of follow-up US in every second year during the following 8 years may be appropriate.

How reliable is secondary risk stratification with stimulated thyroglobulin in patients with differentiated thyroid carcinoma?

Objective: Primary risk factors in patients with differentiated thyroid carcinoma (DTC) are well established. In our institution, secondary risk stratification has been performed with stimulated Thyroglobulin (sTg; TSH > 30 mIU/l) within six months after primary therapy since 2001. In this study, we evaluated the predictive value of sTg for long-term disease- free survival (DFS). Patients, methods: Data of 202 consecutive patients with DTC were analyzed retrospectively. Median follow-up time was 6.4 years (12 months to 16.2 years). Patients were staged according to Union International Contre le Cancer (UICC) criteria. Primary risk stratification was carried out according to European Thyroid Association criteria. Initially, 134 patients (66%) were classified as low-risk and 68 patients (34%) as high-risk. The influence of established risk factors and sTg on DFS was analyzed at three different time points, up to 36 months after initial therapy. Results: In total, 169 (84%) of all patients remained in complete remission after surgery followed by radioiodine-therapy. Six patients (3%) developed tumour recurrence after initial complete remission. Primary risk factors for persistent disease were male sex, follicular or oncocytic tumour, primary tumour > 4 cm in diameter, initial lymph node involvement, initial metastatic disease and microscopic or macroscopic residual tumor. sTg ≤ 0.3 ng/ml measured within six months after initial therapy was a highly significant predictor (p ≤ 0.001) for lasting DFS, 99% of patients with sTg ≤ 0.3 ng/ml were in complete remission 36 months after initial therapy. Conclusions: A stimulated Tg ≤ 0.3 ng/ml within six months after initial therapy is a reliable predictor for long-term disease- free survival independent of primary risk stratification.

Thyroglobulin levels before radioactive iodine therapy and dynamic risk stratification after 1 year in patients with differentiated thyroid cancer

OBJECTIVES

We sought to assess the relationship between stimulated thyroglobulin (sTg) before radioactive iodine therapy (RIT), and the dynamic risk stratification 1 year after treatment, and to establish the utility of the sTg as a predictor of response to therapy in these patients. A retrospective chart review of patients with differentiated thyroid cancer (DTC) who underwent RIT after surgery and were followed for at least 1 year, was carried out.

SUBJECTS AND METHODS

Patients were classified according to the dynamic risk stratification 1 year after initial treatment. The sTg values before RIT were compared among the groups. ROC curve analysis was performed.

RESULTS

Fifty-six patients were enrolled (mean age 44.7 ± 14.4 years, 80.7% had papillary carcinoma). Patients with excellent response had sTg = 2.1 ± 3.3 ng/mL, those with indeterminate response had sTg = 8.2 ± 9.2 ng/mL and those with incomplete response had sTg = 22.4 ± 28.3 ng/mL before RIT (p = 0.01). There was a difference in sTg between excellent and incomplete response groups (p = 0.009) while no difference was found between indeterminate and either excellent or incomplete groups. The ROC curve showed an area under the curve of 0.779 assuming a sTg value of 3.75 ng/mL.

CONCLUSION

Our study results suggest that the higher the sTg before RIT, the greater the likelihood of an incomplete response to initial treatment. A sTg cut-off of 3.75 ng/mL was found to be a good predictor of response to initial treatment in patients with DTC.

Follow-up of patients with thyroglobulin-antibodies: Rising Tg-Ab trend is a risk factor for recurrence of differentiated thyroid cancer

PURPOSE

Differentiated thyroid cancer is the most common endocrine malignancy. Recurrences (5-20%) are the main reason for follow-up. Thyroglobulin (Tg) has proven to be an excellent disease marker, but thyroglobulin-antibodies (Tg-Ab) may interfere with Tg measurement, leading to over or underestimation. It is proposed that the Tg-Ab trend can be used as a marker for disease recurrence, yet few studies define trend and have a long-term follow-up. The objective of our study was to investigate the value of a well-defined Tg-Ab trend as a surrogate marker for disease recurrence during long-term follow-up.

METHODS

We retrospectively studied patients treated at the Nuclear Department of the University Medical Center Utrecht from 1998 to 2010 and the Netherlands Cancer Institute from 2000 to 2009. All patients with Tg-Ab 12 months after treatment were included. The definition of a rise was >50% increase of the Tg-Ab value in a 2 year time period. A decline as >50% decrease of the Tg-Ab value.

RESULTS

Twenty-five patients were included. None of the patients with declining or stable Tg-Ab without a concomitant rise in Tg developed a recurrence. Four patients did suffer a recurrence. Three of these patients had a rising Tg-Ab trend, in two of these patients Tg was undetectable.

CONCLUSIONS

Tg-Ab trend can be used as a crude surrogate marker for long-term follow-up of Tg-Ab patients. A rising trend in Tg-Ab warrants further investigation to detect recurrent disease. Stable or declining Tg-Ab levels do not seem to reflect a risk for recurrence.

Radioiodine Ablation following Thyroidectomy for Differentiated Thyroid Cancer: Literature Review of Utility, Dose, and Toxicity

Management recommendations for differentiated thyroid cancer are evolving. Total thyroidectomy is the backbone of curative-intent therapy, with radioiodine ablation (RAI) of the thyroid remnant routinely performed, in order to facilitate serologic surveillance and reduce recurrence risk. Several single-institution series have identified patient subsets for whom recurrence risk is sufficiently low that RAI may not be indicated. Further, the appropriate dose of RAI specific to variable clinicopathologic presentations remains poorly defined. While recent randomized trials demonstrated equivalent thyroid remnant ablation rates between low- and high-dose RAI, long-term oncologic endpoints remain unreported. While RAI may be employed to facilitate surveillance following total thyroidectomy, cancer recurrence risk reduction is not demonstrated in favorable-risk patients with tumor size ≤1 cm without high-risk pathologic features. When RAI is indicated, in patients without macroscopic residual disease or metastasis, the evidence suggests that the rate of successful remnant ablation following total thyroidectomy is equivalent between doses of 30-50 mCi and doses ≥100 mCi, with fewer acute side effects; however, in the setting of subtotal thyroidectomy or when preablation diagnostic scan uptake is >2%, higher doses are associated with improved ablation rates. Historical series demonstrate conflicting findings of long-term cancer control rates between dose levels; long-term results from modern series have yet to be reported. For high-risk patients, including those with positive surgical margins, gross extrathyroidal extension, lymph node involvement, subtotal thyroidectomy, or >5% uptake, higher-dose RAI therapy appears to provide superior rates of ablation and cancer control.

Preoperative ultrasound-guided carbon nanoparticles localization for metastatic lymph nodes in papillary thyroid carcinoma during reoperation: A retrospective cohort study

Due to the damaged anatomical structure and a large amount of fibrous and scar tissues in the surgical field, reoperation of papillary thyroid carcinoma is difficult. This study introduces a new method of locating metastatic lymph nodes during reoperation and evaluates the effectiveness and safety of the preoperative ultrasound-guided carbon nanoparticles (CNs) localization. This retrospective cohort study enrolled 52 patients who were diagnosed with lymph node metastasis by histopathology and underwent reoperation from October 2015 to February 2016. The modified radical neck dissection or selective neck node dissection was performed. A total of 26 patients underwent preoperative ultrasound-guided CNs injection, and other 26 patients did not. Tolerance, the result of injection, the number of resected metastatic lymph nodes, and postoperative complications were recorded and analyzed. In CNs group, 102 suspicious nonpalpable lesions in 26 patients were injected with CNs, and 99 of the 102 lesions were successfully identified by surgeon in the reoperation. The positive rate of resected lymph nodes in total, in the central compartment, and in the lateral compartment were 31.6%, 31.2%, and 32.8%, respectively, which was significantly higher than that in the control group (P < 0.001, P < 0.001, and P = 0.041). In addition, the positive rates of levels III, IV, and V in the CNs group were 35.6%, 21.9%, and 30.5%, respectively, which was significantly higher than that in the control group (P < 0.001, P = 0.005, and P = 0.01). In additional, in the CNs group, the rate of temporary hypoparathyroidism was significantly lower compared with the control group (0% vs 26.9%, P = 0.021). Preoperative ultrasound-guided CNs injection is a safe and effective method for localization of the metastatic lymph nodes during reoperation.

Thyroid cancer

Thyroid cancer is the fifth most common cancer in women in the USA, and an estimated over 62 000 new cases occurred in men and women in 2015. The incidence continues to rise worldwide. Differentiated thyroid cancer is the most frequent subtype of thyroid cancer and in most patients the standard treatment (surgery followed by either radioactive iodine or observation) is effective. Patients with other, more rare subtypes of thyroid cancer-medullary and anaplastic-are ideally treated by physicians with experience managing these malignancies. Targeted treatments that are approved for differentiated and medullary thyroid cancers have prolonged progression-free survival, but these drugs are not curative and therefore are reserved for patients with progressive or symptomatic disease.

Papillary thyroid carcinomas with biochemical incomplete or indeterminate responses to initial treatment: repeat stimulated thyroglobulin assay to identify disease-free patients

Papillary thyroid cancer (PTC) patients treated with thyroidectomy and radioiodine remnant ablation (RRA) often have detectable TSH-stimulated thyroglobulin (Tg) levels without localizable disease after primary treatment. To assess the value of repeat stimulated Tg assays in these patients' follow-up, we retrospectively analyzed 86 cases followed in 5 Italian thyroid-cancer referral centers. We enrolled 86 patients with PTCs treated with total/near-total thyroidectomy plus RRA between January 1,1990 and January 31, 2006. In all cases, the initial postoperative visit revealed stimulated serum Tg ≥1 ng/mL, negative Tg antibodies, and no structural evidence of disease. None received empiric radioiodine therapy. Follow-up (median: 9.6 years) included neck ultrasound and basal Tg assays (yearly) and at least 1 repeat stimulated Tg assay. Of the 86 patients analyzed (initial risk: low 63 %, intermediate 35 %, high 2 %), one (1 %) had ultrasound-detected lymph node disease and persistently elevated stimulated Tg levels at 3 years. In 17 (20 %), imaging findings were consistently negative, but the final stimulated Tg levels was still >1 ng/mL (median 2.07 ng/mL, range 1.02-4.7). The other 68 (80 %) appeared disease-free (persistently negative imaging findings with stimulated Tg levels ≤1 ng/mL). Mean intervals between first and final stimulated Tg assays were similar (5.2 and 4.8 years) in subgroups with versus without Tg normalization. Reclassification as disease-free was significantly more common when initial stimulated Tg levels were indeterminate (<10 ng/mL). In unselected PTC cohorts with incomplete/indeterminate biochemical responses to thyroidectomy and RRA, periodic remeasurement of stimulated Tg allows most patients to be classified as disease-free.

ENDOCRINE TUMOURS: Imaging in the follow-up of differentiated thyroid cancer: current evidence and future perspectives for a risk-adapted approach

The clinical and epidemiological profiles of differentiated thyroid cancers (DTCs) have changed in the last three decades. Today's DTCs are more likely to be small, localized, asymptomatic papillary forms. Current practice is, though, moving toward more conservative approaches (e.g. lobectomy instead of total thyroidectomy, selective use of radioiodine). This evolution has been paralleled and partly driven by rapid technological advances in the field of diagnostic imaging. The challenge of contemporary DTCs follow-up is to tailor a risk-of-recurrence-based management, taking into account the dynamic nature of these risks, which evolve over time, spontaneously and in response to treatments. This review provides a closer look at the evolving evidence-based views on the use and utility of imaging technology in the post-treatment staging and the short- and long-term surveillance of patients with DTCs. The studies considered range from cervical US with Doppler flow analysis to an expanding palette of increasingly sophisticated second-line studies (cross-sectional, functional, combined-modality approaches), which can be used to detect disease that has spread beyond the neck and, in some cases, shed light on its probable outcome.

Ultrasonographic Evaluation of Cervical Lymph Nodes in Thyroid Cancer

Objective To determine what ultrasonographic features can identify metastatic cervical lymph nodes, both preoperatively and in recurrences after complete thyroidectomy. Study Design Prospective. Setting Outpatient clinic, Department of Head and Neck Surgery, School of Medicine, University of São Paulo, Brazil. Subjects and Methods A total of 1976 lymph nodes were evaluated in 118 patients submitted to total thyroidectomy with or without cervical lymph node dissection. All the patients were examined by cervical ultrasonography, preoperatively and/or postoperatively. The following factors were assessed: number, size, shape, margins, presence of fatty hilum, cortex, echotexture, echogenicity, presence of microcalcification, presence of necrosis, and type of vascularity. The specificity, sensitivity, positive predictive value, and negative predictive value of each variable were calculated. Univariate and multivariate logistic regression analyses were conducted. A receiver operator characteristic (ROC) curve was plotted to determine the best cutoff value for the number of variables to discriminate malignant lymph nodes. Results Significant differences were found between metastatic and benign lymph nodes with regard to all of the variables evaluated ( P < .05). Logistic regression analysis revealed that size and echogenicity were the best combination of altered variables (odds ratio, 40.080 and 7.288, respectively) in discriminating malignancy. The ROC curve analysis showed that 4 was the best cutoff value for the number of altered variables to discriminate malignant lymph nodes, with a combined specificity of 85.7%, sensitivity of 96.4%, and efficiency of 91.0%. Conclusion Greater diagnostic accuracy was achieved by associating the ultrasonographic variables assessed rather than by considering them individually.

Current Guidelines for Postoperative Treatment and Follow-Up of Well-Differentiated Thyroid Cancer

Well-differentiated thyroid cancer is increasing in incidence but the disease-specific mortality remains very low. The only effective adjuvant treatment is radioactive iodine ablation. Guidelines regarding the use and dosage of radioactive iodine depend on pathologic features of the primary and metastatic tumor that define risk. Long-term treatment includes thyroid-stimulating hormone suppression and surveillance with serum thyroglobulin and radiologic assessment for nodal recurrence.

Surgical Management of Lymph Node Compartments in Papillary Thyroid Cancer

Although papillary thyroid cancer (PTC) commonly metastasizes to cervical lymph nodes, prophylactic central neck dissection is controversial. The primary treatment for lymph node metastases is surgical resection. Patients diagnosed with PTC should be assessed preoperatively by cervical ultrasound to evaluate central and lateral neck lymph node compartments. Sonographically suspicious lymph nodes in the lateral neck should be biopsied for cytology or thyroglobulin levels. Any compartment (central or lateral) that has definitive proof of nodal metastases should be formally dissected at the time of thyroidectomy.

Thyroid Cancer in Pediatrics

Well differentiated thyroid cancer (DTC) in children is characterized by a high rate of response to treatment and low disease-specific mortality. Treatment of children with DTC has evolved toward a greater reliance on evaluation and monitoring with serial serum thyroglobulin measurements and ultrasound examinations. Radioiodine therapy is recommended for thyroid remnant ablation in high-risk patients, treatment of demonstrated radioiodine-avid local-regional disease not amenable to surgical resection, or distant radioiodine-avid metastatic disease. Sufficient time should be given for benefits of radioiodine therapy to be realized, with follow-up monitoring. Re-treatment with radioiodine can be deferred until progression of significant disease manifests.

Significance of Low Levels of Thyroglobulin Autoantibodies Associated with Undetectable Thyroglobulin After Thyroidectomy for Differentiated Thyroid Carcinoma

BACKGROUND

The management of patients with differentiated thyroid carcinoma (DTC) showing low levels of serum thyroglobulin autoantibodies (TgAb) and undetectable Tg after thyroidectomy is unsettled. This study sought to elucidate the clinical significance of low levels of TgAb and to evaluate their interference with Tg measurement in vitro.

METHODS

Tg and TgAb levels were correlated with the post-thyroidectomy staging of 177 consecutive DTC patients undergoing (131)I ablation after total thyroidectomy (clinical study). Tg was measured by an immunometric assay (functional sensitivity: 0.1 ng/mL), and TgAb were evaluated by six assays (functional sensitivities: 1.2-96 IU/mL; positive cutoffs: 4-150 IU/mL). The changes in Tg concentration (Tg recovery) of diluted specimens from DTC patients were also measured after incubation with 67 sera from DTC patients with undetectable Tg and low levels of TgAb (in vitro study). DTC sera containing Tg were diluted serially (from 330 to 0.1 ng/mL) and incubated with TgAb samples; Tg was then measured.

RESULTS

In the clinical study: all patients had residual thyroid tissue, and 10 had metastatic disease. Depending on the TgAb assay, median Tg values were 7.0-10.9, 0.0-5.3, and 0.0-0.0 ng/mL in patients with undetectable, borderline (between functional sensitivities and positive cutoffs), and positive TgAb, respectively (p < 0.001). An undetectable Tg value was associated with borderline levels of TgAb in five assays. Only two patients with metastatic disease had undetectable Tg; both were TgAb positive by three or more assays. Conversely, no patient with undetectable Tg and undetectable or borderline TgAb by sensitive assays had metastatic disease. In the in vitro study, TgAb interfered significantly with Tg recovery (p < 0.001), but low levels of TgAb did not abolish Tg recovery.

CONCLUSIONS

While low levels of TgAb do not preclude Tg measurement in vitro, they can be associated with an undetectable Tg in DTC patients with residual thyroid tissue after thyroidectomy. However, the finding of low levels of TgAb by sensitive assays associated with an undetectable Tg rules out metastatic disease.

Thyroid carcinoma in children, adolescents and adults, both spontaneous and after childhood radiation exposure

Thyroid carcinoma is the most common second malignancy for childhood cancer survivors. Radiation exposure is linked to risk. Thyroid nodules in children have a high risk for malignancy, whether spontaneous or after radiation. Due to the extremely limited available paediatric data, we sought to review a series of patients with thyroid carcinoma, seen over 25 years. Forty-six patients were identified. Thirty-nine (84.8 %) had papillary thyroid carcinoma, five (10.9 %) follicular carcinoma and 2 (4.3 %) medullary thyroid carcinoma (MEN2B). Thirty-three (71.7 %) had childhood radiation exposure (17 females) with thyroid malignancy occurring 6-37 years later. The smallest nodule size found on surveillance to have thyroid malignancy was 4 mm. Thyroid cancer in patients 16 years and under was seen in 22 patients (47.8 %). All had total thyroidectomy, with initial central node clearance from 2005. Diagnostic rTSH stimulated I(123) scan was followed by ablative I(131) if any uptake was seen. Sixteen (32.6 %) had metastases. Twenty-four (52.2 %) had I(131), four requiring multiple courses. Forty-two remain alive and well.

CONCLUSION

Ultrasound screening is required for early diagnosis as small nodule size is not predictive of benign histology or absence of metastases. Central node clearance provides better outcome. Despite metastatic disease at presentation for some, prognosis is favourable.

WHAT IS KNOWN

• Incidence of thyroid cancer has been increasing and radiation exposure in childhood cancer survivors is clearly linked to risk. • Published guidelines in many places can only provide very low level evidence due to extremely limited available paediatric data. What is New: • Paper provides good evidence to confirm existing views with the largest cohort of thyroid cancer reported to date in the paediatric age group in Australia, and the largest cohort in Australia where there have been specific high risks of radiation exposure. The only other reported larger studies have come from the Children's Oncology Group and Childhood Cancer Survivor Study [24]. • Using diagnostic rTSH stimulated I(123) scan 6 weeks after surgery helps to determine if radioactive iodine ablation is necessary and limits unnecessary bone marrow exposure for young patients in whom future leukaemia is of greater concern.

Comparison of Antithyroglobulin Antibody Concentrations Before and After Ablation with 131I as a Predictor of Structural Disease in Differentiated Thyroid Carcinoma Patients with Undetectable Basal Thyroglobulin and Negative Neck Ultrasonography

BACKGROUND

Patients with differentiated thyroid carcinoma are submitted to a first assessment several months after initial therapy to evaluate their response to treatment. At that assessment, measurement of basal thyroglobulin (Tg) and antithyroglobulin antibodies (TgAb) and neck ultrasonography (US) are recommended. Serum Tg may be falsely negative in the presence of TgAb, and the management of patients with negative Tg but positive TgAb represents a challenge. The objective of this study was to correlate the variation in TgAb concentrations (comparison before and after ablation with (131)I) with the risk of structural disease.

METHODS

The sample consisted of 116 low- or intermediate-risk patients who had undetectable Tg, negative US at initial assessment, and positive TgAb 8-12 months after thyroidectomy and ablation with (131)I.

RESULTS

Comparison of TgAb concentrations before and after ablation with (131)I showed a reduction of >50% in 56 patients (group A), a reduction of <50% in 35 patients (group B), and an increase in 25 patients (group C). Metastases were detected in 5/116 (4.3%) patients during initial assessment (lymph nodes in two, pulmonary in two, and bone in one). They were diagnosed in 0/56, 2/35 (5.7%), and 3/25 (12%) patients of groups A, B, and C, respectively. During follow-up, metastases were detected in 7/111 (6.3%) patients (lymph nodes in six, and pulmonary in one). They occurred in 1/56 (1.8%), 3/33 (9%), and 3/22 (13.6%) patients of groups A, B, and C, respectively. Thus, structural disease was found in 1.8%, 14.3%, and 24% of groups A, B, and C, respectively. This rate was 4% in low-risk patients and 15.4% in intermediate-risk patients.

CONCLUSIONS

Among patients with undetectable Tg, negative US, and positive TgAb after ablation with (131)I, the frequency of structural disease was <5% in patients, with >50% reduction in TgAb. Among patients without a significant reduction in TgAb, approximately 10% of low-risk patients and >20% of intermediate-risk patients had structural disease. These results help define the indication for imaging methods other than US during initial assessment and long-term follow-up.

Ultrasound-based clinical prediction rule model for detecting papillary thyroid cancer in cervical lymph nodes: A pilot study

PURPOSE

To identify sonographic features of cervical lymph nodes (LNs) that are associated with papillary thyroid cancer (PTC) and to develop a prediction model for classifying nodes as metastatic or benign.

METHODS

This retrospective study included the records of postthyroidectomy patients with PTC who had undergone cervical ultrasound and LN biopsy. LN location, size, shape, hilum, echopattern, Doppler flow, and microcalcifications were assessed. Model selection was used to identify features associated with malignant LNs and to build a predictive, binary-outcome, generalized linear mixed model. A cross-validated receiver operating characteristic analysis was conducted to assess the accuracy of the model for classifying metastatic nodes.

RESULTS

We analyzed records from 71 LNs (23 metastatic) in 44 patients (16 with PTC). The predictive model included a nonhomogeneous echopattern (odds ratio [OR], 5.73; 95% confidence interval [CI], 1.07-30.74; p = 0.04), microcalcifications (OR, 4.91; 95% CI, 0.91-26.54; p = 0.06), and volume (OR, 2.57; 95% CI, 0.66-9.99; p = 0.16) as predictors. The model had an area under the curve of 0.74 (95% CI, 0.60-0.85), sensitivity of 65% (95% CI, 50% to 78%), and specificity of 85% (95% CI, 73% to 94%) at the Youden optimal cut point of 0.38.

CONCLUSIONS

Nonhomogeneous echopattern, microcalcifications, and node volume were predictive of malignant LNs in patients with PTC. A larger sample is needed to validate this model.

Recommendations for post-surgical thyroid ablation in differentiated thyroid cancer: a 2015 position statement of the Italian Society of Endocrinology

Post-surgical ablation of thyroid remnant with radioactive iodine (RAI) in differentiated thyroid cancer (DTC) is aimed to destroy any thyroid remnant in the thyroid bed (remnant ablation) and any microscopic foci of cancer cells eventually present within the thyroid remnant (adjuvant therapy). The present text is an attempt to offer practice guidelines for the indication of thyroid ablation and the preparation of DTC patients considering the latest achievement in the field and the changing epidemiology of DTC observed in the last 10 years.

METHODOLOGY

The executive committee of the Italian Society of Endocrinology appointed a task force of thyroid cancer expert including Nuclear Medicine Physicians and Endocrinologists to provide a consensus on the post-surgical ablation in thyroid cancer patients. The task force had no conflict of interest and had no commercial support. A number of specific topics were selected and the members selected relevant papers by searching in the Pubmed for articles published from 2000 to January 2015. Selected studies were categorized by level of evidence, and the recommendations were graded according to the level of evidence as high (A), moderate (B), or low (C).