Poorly differentiated thyroid carcinoma presenting with gross extrathyroidal extension: 1986-2009 Memorial Sloan-Kettering Cancer Center experience

ENDOCAN-TUTHYREF guidelines. Locoregional therapies for locally advanced and/or metastatic thyroid cancer

This article presents consensus recommendations by a multidisciplinary panel of endocrinologists, medical oncologists, pathologists, radiation oncologists, surgeons and nuclear medicine physicians. The recommendations specifically address iodine-refractory well-differentiated thyroid carcinoma and locally advanced and/or metastatic medullary thyroid carcinoma. Treatment algorithms based on risk-benefit assessments of various multimodal therapeutic approaches are proposed for each clinical scenario. Given the limited data available on the management of these rare but aggressive forms of thyroid cancer, these consensus recommendations provide essential guidance for multidisciplinary teams to ensure optimal care for patients with these complex thyroid carcinomas.

The 2024 revised clinical guidelines on the management of thyroid tumors by the Japan Association of Endocrine Surgery

The Japan Association of Endocrine Surgery published the first edition of the "Clinical guidelines on the management of thyroid tumors" in 2010 and the revised edition in 2018. The guideline presented herein is the English translation of the revised third edition, issued in 2024. The aim is to enhance health outcomes for patients suffering from thyroid tumors by facilitating evidence-based shared decision-making between healthcare providers and patients, as well as standardizing the management of thyroid tumors. The focus is on adult patients with thyroid tumors, addressing clinically significant issues categorized into areas such as an overview of the diagnosis and treatment of thyroid nodules, treatment strategies by histological type, radioactive iodine therapy, treatment of advanced differentiated carcinoma, pharmacotherapy, and complications and safety management associated with thyroid surgery. Thirty-two clinical questions were established in these areas. Following a comprehensive search of the literature and systematic review to evaluate the overall evidence, we aimed to present optimal recommendations by considering the balance of benefits and harms from the patient's perspective. We integrated evidence and clinical experience to determine the "Certainty of evidence" and "Strength of recommendations". Based on these, we illustrated overall flows of care as "Clinical algorithms". Necessary background knowledge of diseases and established clinical procedures for understanding the recommendations are presented in "Notes", while information that may be clinically useful but for which evidence remains insufficient is included in "Columns", based on the current state of evidence. Finally, future challenges for the next revision are presented as "Future research questions".

Aggressive Types of Malignant Thyroid Neoplasms

Differentiated thyroid cancer (DTC) includes many subtypes, which demonstrate favorable to aggressive behavior. During the past decades, efforts have been made to describe aggressive thyroid cancers. Within DTC, aggressive variants constitute rare entities with unique histopathological features and compromised survival, as local and distant metastatic disease is frequent. In recent years, the distinct category of poorly differentiated thyroid cancer was introduced in 2004 and the type of differentiated high-grade thyroid carcinoma was recently added in the 2022 WHO classification of thyroid neoplasms. Finally, anaplastic thyroid cancer exhibits a rapid, resistant to therapy, progression and confers the shortest survival. In this review, we will present the characteristics of these thyroid cancer types and also discuss the treatment, management, and follow-up of these difficult cases. Emphasis was given to recent bibliography of the last decade.

Poorly differentiated thyroid cancer: Clinical, pathological, mutational, and outcome analysis

INTRODUCTION

Poorly differentiated thyroid cancer (PDTC) remains a challenge not only for pathologists and surgeons because of the difficulties associated with the diagnostic process and the compelling need for difficult thyroidectomy, but it is also of high clinical relevance because it is responsible for mortality in non-anaplastic follicular cell-derived thyroid cancer.

MATERIALS AND METHODS

Cases of PDTC within a 30-year period were reviewed by two independent pathologists. Histological features like atypical mitosis, necrosis, capsular, and vascular invasion were studied. Mutation analysis was done for BRAF, RET/PTC, RAS, and PI3KCA, and P53 was performed using immunohistochemistry.

RESULTS

There were 39 patients with a median age of 53 years; 14 patients were more than 55 years of age. At presentation, 38.4% had compressive features and the median tumor size was 9 cm. At presentation, 67.7% had an extrathyroidal extension (ETE). R0 resection was achieved in 41%, with 12 cases resulting in a difficult thyroidectomy. Necrosis was seen in 65.7% and mitosis in 73.3% with well-differentiated components in 41%. The commonest mutation was RAS (23.1%). Survival was higher in the operable group (54.26, 95% confidence interval [CI]: 30.83-77.70 vs. 20.25, 95% CI: 0-54.07) months, respectively; however, 10-year survival was only 5% and only the tumor size and presence of mitosis were independent risk factors.

CONCLUSION

PDTC presents with worrisome features like large size, ETE, and rapid growth. Aggressive surgical resection with extended/radical thyroidectomy may result in better loco-regional control and improved survival. RAS was the frequent mutation detected. It is worthwhile to identify prognostic factors that can predict the course of PDTC.

Prognosis of Poorly Differentiated Thyroid Carcinoma: A Systematic Review and Meta-Analysis

BACKGRUOUND

Poorly differentiated thyroid carcinoma (PDTC) accounts for a small portion of thyroid carcinomas but contributes to a significant proportion of thyroid carcinoma-associated deaths. The clinicopathological prognostic factors and clinical outcomes of PDTC remain unclear. We aimed to evaluate the clinical outcomes of patients with PDTC after curative treatment.

METHODS

A comprehensive search was performed up to September 2023. We included studies investigating treatment outcomes in patients with PDTC who underwent initial surgery. The 5-year disease-free survival (DFS) and overall survival (OS) were extracted. In this meta-analysis, the enrolled PDTC histological criteria included 3rd, 4th, and 5th World Health Organization (WHO) and Memorial Sloan Kettering Cancer Center (MSKCC) classification. A random-effects model was used for the pooled proportion analysis. Meta-regression analysis was conducted to evaluate the prognostic factors.

RESULTS

Twenty retrospective studies published between 2007 and 2023, including 1,294 patients, met all inclusion criteria. Studies that diagnosed PDTC based on various histological criteria including 3rd WHO (n=5), 4th WHO (n=12), 5th WHO (n=2), and MSKCC (n=1) were included. Overall, 5-year DFS and 5-year OS were 49.4% (95% confidence interval [CI], 42.3 to 56.4) and 73.8% (95% CI, 66.5 to 79.9), with moderate heterogeneity of 58% and 55%, respectively. In meta-regression analysis, extrathyroidal extension (ETE) was a prognostic factor for OS.

CONCLUSION

The meta-analysis of DFS and OS in patients with PDTC show the moderate heterogeneity with a variety of histological criteria. ETE appears to have a significant impact on OS, regardless of histological criteria.

Management of Poorly Differentiated Thyroid Cancer and Differentiated High-Grade Thyroid Carcinoma

Thyroid carcinoma of follicular cell origin exists on a histopathologic and clinical spectrum. The authors focus on the category of tumors that fall between the very favorable well-differentiated thyroid carcinomas and the very unfavorable anaplastic thyroid carcinomas. These intermediately aggressive tumors include poorly differentiated thyroid carcinoma and the newly defined differentiated high-grade thyroid carcinoma. Both diagnoses require certain histopathologic requirements be met in order to accurately identify these tumors post-operatively. Management remains primarily surgical though adjunctive treatments such as molecular targeted therapies (eg, tyrosine kinase inhibitors) and differentiation therapy (to restore tumor response to radioactive iodine) are also becoming available.

A Comprehensive Review and Insights into the New Entity of Differentiated High-Grade Thyroid Carcinoma

Differentiated high-grade thyroid carcinoma (DHGTC) is a new subset within the spectrum of thyroid malignancies. This review aims to provide a comprehensive overview of DHGTC, focusing on its historical perspective, diagnosis, clinical characteristics, molecular profiles, management, and prognosis. DHGTC demonstrates an intermediate prognosis that falls between well-differentiated thyroid carcinoma and anaplastic thyroid carcinoma. Previously unenumerated, this entity is now recognized for its significant impact. Patients with DHGTC often present at an older age with advanced disease and exhibit aggressive clinical behavior. Molecularly, DHGTC shares similarities with other thyroid malignancies, harboring driver mutations such as BRAFV600E and RAS, along with additional late mutations. The unique behavior and histologic features of DHGTC underscore the necessity of precise classification for prognostication and treatment selection. This highlights the critical importance of accurate diagnosis and recognition by pathologists to enrich future research on this entity further.

Poorly differentiated thyroid carcinoma: molecular, clinico-pathological hallmarks and therapeutic perspectives

Poorly differentiated thyroid carcinoma (PDTC) is a rare and extremely aggressive tumor, accounting for about 2-15% of all thyroid cancer. PDTC has a distinct biological behavior compared to well-differentiated and anaplastic thyroid carcinoma and, in last years, it has been classified as a separate entity from both anatomopathological and clinical points of view. Nevertheless, there is still a lack of consensus among clinicians regarding inclusion criteria and definition of PDTC that affects its diagnosis and clinical management. Due to its rarity and difficulty in classification compared to other tumors, very few studies are available to date and series often include different histotypes in addition to PDTC. This review focuses on main studies concerning PDTC summarizing the evolution in the definition of its diagnosis criteria, clinicopathological features, management, and outcome. The data available confirm that the pathological evaluation and classification of PDTC are crucial and should therefore be standardized. Since the clinical presentation and prognosis of PDTC may vary widely depending on the different stage of the disease at diagnosis, the patient's management may differ in treatment and should be tailored to each patient. Finally, this review discusses advances in molecular insights of PDTC that, together with the implementation of both in vitro and in vivo models, will provide valuable insights into biological mechanisms of progression, metastasis, and invasion of this aggressive thyroid carcinoma. Further studies on larger, carefully selected series are needed to better assess the peculiar features of PDTC and to better define its management by focusing on the best diagnostic and therapeutic approaches.

Poorly differentiated thyroid carcinomas: conceptual controversy and clinical impact

Poorly differentiated thyroid carcinomas (PDTC) are rare diseases; nevertheless, they account for the majority of deaths from non-anaplastic follicular cell-derived thyroid carcinomas. Establishing the diagnosis and treatment of PDTC is challenging given the low incidence and the lack of standardization of diagnostic criteria. These limitations hamper the ability to compare therapeutic modalities and outcomes between recent and older studies. Recently, the 5th edition of the classification of endocrine tumors has been published, which includes changes in nomenclature and the addition of the disease entity of "differentiated high-grade follicular cell-derived carcinomas". On the other hand, the recently witnessed advances in molecular diagnostics have enriched therapeutic options and improved prognosis for patients. We herein review the various historical variations and evolution in the diagnostic criteria for PDTC. This systematic review attempts to clarify the evolution of the histological and molecular characteristics of this disease, its prognosis, as well as its treatment options.

A Review of Evidence for the Involvement of the Circadian Clock Genes into Malignant Transformation of Thyroid Tissue

(1) Background: In 2013, the results of a pioneer study on abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in cancerous thyroid nodules was published. In the following years, new findings suggesting the involvement of circadian clockwork dysfunction into malignant transformation of thyroid tissue were gradually accumulating. This systematic review provides an update on existing evidence regarding the association of these genes with thyroid tumorigenesis. (2) Methods: Two bibliographic databases (Scopus and PubMed) were searched for articles from inception to 20 March 2023. The reference lists of previously published (nonsystematic) reviews were also hand-searched for additional relevant studies. (3) Results: Nine studies published between 2013 and 2022 were selected. In total, 9 of 12 tested genes were found to be either up- or downregulated. The list of such genes includes all families of core circadian clock genes that are the key components of three transcriptional-translational feedback loops of the circadian clock mechanism (BMAL1, CLOCK, NPAS2, RORα, REV-ERBα, PERs, CRYs, and DECs). (4) Conclusions: Examination of abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in thyroid tissue can help to reduce the rate of inadequate differential preoperative diagnosis for thyroid carcinoma.

Ultrasound, laboratory and histopathological insights in diagnosing papillary thyroid carcinoma in a paediatric population: a single centre follow-up study between 2000-2022

Background

Papillary thyroid carcinoma (PTC) often coincides with autoimmune thyroiditis (AIT); whether this association is incidental or causal remains debated.

Objective

To evaluate the ultrasonographic, laboratory, and histopathological features of PTC in paediatric patients with and without AIT and its relationship to puberty.

Design

A retrospective cohort study.

Patients and methods

A retrospective analysis of medical records of 90 patients (69; 76.7% females). The mean age at PTC diagnosis was 13.8 years [range 6-18]. All patients were evaluated ultrasonographically before thyroid surgery. Thyroid nodules were categorised using the European Thyroid Imaging Reporting and Data System (EU-TIRADS PL), and cytopathology was assessed using Bethesda criteria. Neck ultrasound results and thyroid and autoimmune status were correlated with histopathological PTC assessment.

Results

The coexistence of PTC and AIT was found in 48.9% (44/90) of patients. The percentage of AIT was increasing with age; AIT was present only in 1/3 of prepubertal, close to 50% in pubertal, and over 60% in adolescent patients. The youngest patients (aged <10 years old) presented more often with goitre and lymphadenopathy and less often with AIT than adolescents (15-18 years of age). There were no differences in TPOAb, TgAb, and TSH levels between the age subgroups. Presurgical TgAb levels were higher than those of TPOAb in the youngest patients. Histopathological analysis revealed that the solid subtype was observed more often in prepubertal children and diffuse sclerosing in children below 14 years of age, whereas the classic subtype dominated in late pubertal. Univariate and multivariate analyses revealed that lymph nodes metastases (LNM) were associated with PTC diameter and fT4 level, whereas extrathyroidal extension with age and angioinvasion with PTC diameter and age. The correlations between age and fibrosis, and the presence of psammoma bodies in malignant tissues were close to significant. We did not observe an association between TSH levels and the presence of autoimmunity and PTC variables.

Conclusions

In paediatric patients the natural course of PTC may be less aggressive in adolescent patients than in younger children (especially < 10 years of age). We suggest that pre-operative evaluation of paediatric patients with thyroid nodules could include apart from assessment of thyroid hormones, evaluation of TPOAb, TgAb, and TRAb together with comprehensive neck ultrasonography.

"Time" for obesity-related cancer: The role of the circadian rhythm in cancer pathogenesis and treatment

The circadian rhythm is regulated by an intrinsic time-tracking system, composed both of a central and a peripheral clock, which influences the cycles of activities and sleep of an individual over 24 h. At the molecular level, the circadian rhythm begins when two basic helix-loop-helix/Per-ARNT-SIM (bHLH-PAS) proteins, BMAL-1 and CLOCK, interact with each other to produce BMAL-1/CLOCK heterodimers in the cytoplasm. The BMAL-1/CLOCK target genes encode for the repressor components of the clock, cryptochrome (Cry1 and Cry2) and the Period proteins (Per1, Per2 and Per3). It has been recently demonstrated that the disruption of circadian rhythm is associated with an increased risk of developing obesity and obesity-related diseases. In addition, it has been demonstrated that the disruption of the circadian rhythm plays a key role in tumorigenesis. Further, an association between the circadian rhythm disruptions and an increased incidence and progression of several types of cancer (e.g., breast, prostate, colorectal and thyroid cancer) has been found. As the perturbation of circadian rhythm has adverse metabolic consequences (e.g., obesity) and at the same time tumor promoter functions, this manuscript has the aim to report how the aberrant circadian rhythms affect the development and prognosis of different types of obesity-related cancers (breast, prostate, colon rectal and thyroid cancer) focusing on both human studies and on molecular aspects.

Advances in Thyroid Pathology: High Grade Follicular Cell-derived Thyroid Carcinoma and Anaplastic Thyroid Carcinoma

In the upcoming World Health Organization fifth edition classification of endocrine tumors, there were several major changes related to high grade follicular-derived thyroid carcinoma (HGFCTC) and anaplastic thyroid carcinoma (ATC) based on emerging evidence about the diagnostic criteria clinical behavior, prognostic factors, and molecular signatures of these tumors. In this review, we aim to summarize the major evolutions of HGFCTC and ATC. HGFCTC is a nonanaplastic carcinoma with high grade features (High mitotic count, tumor necrosis). It is subdivided into poorly differentiated thyroid carcinoma diagnosed using the Turin proposal and differentiated high grade thyroid carcinoma. The latter is defined by the presence of the cytoarchitectutal features of well-differentiated thyroid carcinoma (eg, papillae) but harbors elevated mitotic activity and/or tumor necrosis. Poorly differentiated thyroid carcinoma is predominantly RAS -driven and associated with RAI avidity and high propensity for distant metastasis, whereas differentiated high grade thyroid carcinoma is mostly BRAFV600E -driven. ATC may show a wide range of histologic features. Carcinoma of pure squamous phenotype is associated with a high frequency of BRAF V600E mutations and is now considered as a subtype of ATC. There is a stepwise molecular progression from well-differentiated carcinoma to HGFCTC to ATC manifested by 1) early and persistent driver alteration in the MAPK pathway, particularly BRAF V600E and RAS mutations, and 2) gain of secondary aggressive molecular signatures (such as TERT promoter and TP53 mutations) when tumors progress from well-differentiated to high grade to anaplastic carcinoma.

Molecular features of aggressive thyroid cancer

Poorly differentiated thyroid cancer (PDTC) and anaplastic thyroid cancer (ATC) have a worse prognosis with respect to well differentiated TC, and the loss of the capability of up-taking ¹³¹I is one of the main features characterizing aggressive TC. The knowledge of the genomic landscape of TC can help clinicians to discover the responsible alterations underlying more advance diseases and to address more tailored therapy. In fact, to date, the antiangiogenic multi-targeted kinase inhibitor (aaMKIs) sorafenib, lenvatinib, and cabozantinib, have been approved for the therapy of aggressive radioiodine (RAI)-resistant papillary TC (PTC) or follicular TC (FTC). Several other compounds, including immunotherapies, have been introduced and, in part, approved for the treatment of TC harboring specific mutations. For example, selpercatinib and pralsetinib inhibit mutant RET in medullary thyroid cancer but they can also block the RET fusion proteins-mediated signaling found in PTC. Entrectinib and larotrectinib, can be used in patients with progressive RAI-resistant TC harboring TRK fusion proteins. In addition FDA authorized the association of dabrafenib (BRAF^V600E inhibitor) and trametinib (MEK inhibitor) for the treatment of BRAF^V600E-mutated ATC. These drugs not only can limit the cancer spread, but in some circumstance they are able to induce the re-differentiation of aggressive tumors, which can be again submitted to new attempts of RAI therapy. In this review we explore the current knowledge on the genetic landscape of TC and its implication on the development of new precise therapeutic strategies.

Papillary Thyroid Carcinoma With Breast and Bone Metastasis

Papillary thyroid carcinoma is the most common thyroid malignant tumor and usually has a fine prognosis. The most common metastatic site is the cervical lymph node, and distant metastasis is rare. This report describes a female patient with papillary thyroid carcinoma who presented with multiple metastases in the cervical lymph nodes, breast, and spine. The patient's disease course lasted 11 years, and eventually metastatic cancer led to the patient's death. We also analyzed the survival rate and median survival time of papillary thyroid carcinoma with multiple organ metastases using data in the literature.

Prospects of Testing Diurnal Profiles of Expressions of TSH-R and Circadian Clock Genes in Thyrocytes for Identification of Preoperative Biomarkers for Thyroid Carcinoma

Thyroid Nodules (TN) are frequent but mostly benign, and postoperative rate of benign TN attains the values from 70% to 90%. Therefore, there is an urgent need for identification of reliable preoperative diagnosis markers for patients with indeterminate thyroid cytology. In this study, an earlier unexplored design of research on preoperative biomarkers for thyroid malignancies was proposed. Evaluation of reported results of studies addressing the links of thyroid cancer to the circadian clockwork dysfunctions and abnormal activities of Thyroid-Stimulating Hormone (TSH) and its receptor (TSH-R) suggested diagnostic significance of such links. However, there is still a gap in studies of interrelationships between diurnal profiles of expression of circadian clock genes and TSH-R in indeterminate thyroid tissue exposed to different concentrations of TSH. These interrelationships might be investigated in future in vitro experiments on benign and malignant thyrocytes cultivated under normal and challenged TSH levels. Their design requires simultaneous measurement of diurnal profiles of expression of both circadian clock genes and TSH-R. Experimental results might help to bridge previous studies of preoperative biomarkers for thyroid carcinoma exploring diagnostic value of diurnal profiles of serum TSH levels, expression of TSH-R, and expression of circadian clock genes.

Aggressive variants of follicular cell-derived thyroid carcinoma: an overview

PURPOSE

The incidence of thyroid carcinoma has increased globally in the past years. Papillary thyroid carcinoma (PTC) is the most frequent neoplasm of the thyroid gland comprehending the 90% of the thyroid carcinoma and has an indolent clinical behaviour. However, some variants of follicular cell-derived thyroid carcinoma, including variants of classic of PTC, have been identified that show a more aggressive biological behaviour. An accurate diagnosis of these entities is crucial for planning a more aggressive treatment and improving patients' prognosis of patients. The aim of this review is to present the main clinical, histological, and molecular features of aggressive variants of follicular cell-derived thyroid carcinoma, and to provide useful histological parameters for determining the most suitable therapeutic strategy for patients affected by these forms.

RESULTS

Variants of classic PTC such as the diffuse sclerosing variant (DSV), the tall cell variant (TCV), the columnar cell variant (CCV), the solid/trabecular variant (STV) and the hobnail variant (HV), and other variants of follicular cell-derived thyroid carcinoma, such as poorly differentiated thyroid carcinoma (PDTC), and anaplastic thyroid carcinoma (ATC), are associated with aggressive behaviour.

CONCLUSIONS

The correct identification and diagnosis of aggressive variants of follicular cell-derived thyroid carcinoma is important, as they allow the clinician to adopt the most refined therapeutic strategies in order to the survival of the patients.

Poorly differentiated thyroid carcinoma: a clinician's perspective

Poorly differentiated thyroid carcinoma (PDTC) is a rare thyroid carcinoma originating from follicular epithelial cells. No explicit consensus can be achieved to date due to sparse clinical data, potentially compromising the outcomes of patients. In this comprehensive review from a clinician's perspective, the epidemiology and prognosis are described, diagnosis based on manifestations, pathology, and medical imaging are discussed, and both traditional and emerging therapeutics are addressed as well. Turin consensus remains the mainstay diagnostic criteria for PDTC, and individualized assessments are decisive for treatment option. The prognosis is optimal if complete resection is performed at early stage but dismal in nearly half of patients with locally advanced and/or distant metastatic diseases, in which adjuvant therapies such as 131I therapy, external beam radiation therapy, and chemotherapy should be incorporated. Emerging therapeutics including molecular targeted therapy, differentiation therapy, and immunotherapy deserve further investigations to improve the prognosis of PDTC patients with advanced disease.

Postoperative external beam radiotherapy for locoregional control in iodine refractory differentiated thyroid cancer

Background

The role of postoperative external beam radiotherapy (EBRT) in patients with residual iodine refractory-differentiated thyroid cancer (IR-DTC) is still inconclusive. The aim of this retrospective study was to evaluate locoregional control (LRC) and overall survival (OS), and potential side effects after postoperative EBRT for both microscopic and macroscopic non-radically resected, locally advanced IR-DTC.

Methods

Between 1990 and 2016, 49 patients with locally advanced IR-DTC received EBRT for microscopic (R1; n = 28) or macroscopic (R2; n = 21) locoregional residual disease. For more insight into the added effect of EBRT, we performed an intrapatient sub-analysis in 32 patients who had undergone more than 1 surgical intervention, comparing LRC after primary, curative-intended surgery with LRC after repeated surgery plus EBRT. To estimate LRC and OS, we used Kaplan-Meier curves. From 2007 onward, we prospectively recorded toxicity data in our head and neck cancer database (n = 10).

Results

LRC rates 5 years after EBRT were higher for R1 (84.3%) than for R2 (44.9%) residual disease (P = 0.016). The 5-year OS rate after EBRT was 72.1% for R1 and 33.1% for R2 disease (P = 0.003). In the intrapatient analysis (n = 32), LRC rates were 6.3% 5 years after only initial surgery and 77.9% after repeated surgery with EBRT (P < 0.001). Acute toxicity was limited to grade I and II xerostomia, mucositis, and hoarseness; only one patient developed late grade III dysphagia.

Conclusions

Postoperative EBRT is associated with long-lasting LRC and OS with acceptable toxicity in patients with locally advanced IR-DTC, especially in microscopic residual disease.

Poorly Differentiated Thyroid Carcinoma: Single Centre Experience and Review of the Literature

There is controversy in the literature regarding a distinct subset of thyroid carcinoma whose histologically classification falls between well-differentiated and anaplastic carcinomas, previously identified as 'poorly differentiated thyroid carcinoma' (PDTC), or 'insular carcinoma', in view of the peculiar morphological characteristics of the cell groupings. The correct diagnosis and treatment of this entity have important prognostic and therapeutic significance. In this review, we describe the epidemiology, diagnosis, and management of PDTC and report our single centre experience to add to the limited evidence existing in the literature.

Novel Inhibitor-Based Therapies for Thyroid Cancer-An Update

Thyroid cancers (TCs) are the most common tumors of the endocrine system and a constant rise in the number of TC cases has been observed for the past few decades. TCs are one of the most frequent tumors in younger adults, especially in women, therefore early diagnosis and effective therapy are especially important. Ultrasonography examination followed by fine needle biopsy have become the gold standard for diagnosis of TCs, as these strategies allow for early-stage detection and aid accurate qualification for further procedures, including surgical treatment. Despite all the advancements in detection and treatment of TCs, constant mortality levels are still observed. Therefore, a novel generation line of targeted treatment strategies is being developed, including personalized therapies with kinase inhibitors. Recent molecular studies on TCs demonstrate that kinase inhibitor-based therapies might be considered as the most promising. In the past decade, new kinase inhibitors with different mechanisms of action have been reported and approved for clinical trials. This review presents an up-to-date picture of new approaches and challenges of inhibitor-based therapies in treatment of TCs, focusing on the latest findings reported over the past two years.

Secretory Carcinoma of the Thyroid in a 49-Year-Old Man Treated with Larotrectinib: Protracted Clinical Course of Disease Despite the High-Grade Histologic Features

Secretory carcinoma of the thyroid gland is histologically and genetically similar to its mammary and salivary gland counterparts. Unlike differentiated thyroid carcinomas of follicular cell origin, thyroid SC is not a thyroglobulin-producing tumor and would not be amenable to radioactive iodine therapy. Instead, these carcinomas may respond to targeted therapy with TRK inhibitors, which further emphasizes the importance of their recognition among morphologically similar thyroid entities. Based on eleven cases reported to date, most primary thyroid SC tend to present as locally advanced malignancies and are characterized by frequent recurrences and long-term survival. High-grade histologic features, increased mitotic count and necrosis have been described but their impact on clinical course and outcome remains unclear. We hereby report the case of a primary SC with high-grade features arising in the thyroid of a 49-year-old man, who was treated with Larotrectinib for his second recurrence. The patient achieved a durable response that lasted for 18 months but then he continued to progress and died of disease 181 months after the diagnosis.

Differentiating pulmonary metastasis from benign lung nodules in thyroid cancer patients using dual-energy CT parameters

OBJECTIVES

To explore the importance of quantitative characteristics of dual-energy CT (DECT) between pulmonary metastasis and benign lung nodules in thyroid cancer.

METHODS

In this retrospective study, we identified 63 patients from our institution's database with pathologically proven thyroid cancer who underwent DECT to assess pulmonary metastasis. Among these patients, 22 had 55 pulmonary metastases, and 41 had 97 benign nodules. If nodules showed increased iodine uptake on I-131 single-photon emission computed tomography-computed tomography or increased size in follow-up CT, they were considered metastatic. We compared the clinical findings and DECT parameters of both groups and performed a receiver operating characteristic analysis to evaluate the optimal cutoff values of the DECT parameters.

RESULTS

Patients with metastases were significantly older than patients with benign nodules (p = 0.048). The DECT parameters of the metastatic nodules were significantly higher than those of the benign nodules (iodine concentration [IC], 5.61 ± 2.02 mg/mL vs. 1.61 ± 0.98 mg/mL; normalized IC [NIC], 0.60 ± 0.20 vs. 0.16 ± 0.11; NIC using pulmonary artery [NIC_PA], 0.60 ± 0.44 vs. 0.15 ± 0.11; slope of the spectral attenuation curves [λHU], 5.18 ± 2.54 vs. 2.12 ± 1.39; and Z-effective value [Z_eff], 10.0 ± 0.94 vs. 8.79 ± 0.75; all p < 0.001). In the subgroup analysis according to nodule size, all DECT parameters of the metastatic nodules in all subgroups were significantly higher than those of the benign nodules (all p < 0.05). The cutoff values for IC, NIC, λHU, NIC_PA, and Z_eff for diagnosing metastases were 3.10, 0.29, 3.57, 0.28, and 9.34, respectively (all p < 0.001).

CONCLUSIONS

DECT parameters can help to differentiate metastatic and benign lung nodules in thyroid cancer.

KEY POINTS

• DECT parameters can help to differentiate metastatic and benign lung nodules in patients with thyroid cancer. • DECT parameters showed a significant difference between benign lung nodules and lung metastases, even for nodules with diameters ≥ 3 mm and < 5 mm. • Among the DECT parameters, the highest diagnostic accuracy for differentiating pulmonary metastases from benign lung nodules was achieved with the NIC and IC, followed by the NIC_PA and λHU, and their cutoff values were 0.29, 3.10, 0.28, and 3.57, respectively.

Neoadjuvant lenvatinib for inoperable thyroid cancer: A case report and literature review

Background

Poorly differentiated thyroid cancer (PDTC) is now classified as a separate thyroid tumor entity. It has male predominance and poor prognosis compared to differentiated TC.

Case

We report a case of a patient with PDTC who was previously deemed inoperable. A trial of neoadjuvant lenvatinib therapy was given to the patient after that the tumor become operable and the surgery went successfully.

Conclusions

Lenvatinib is a feasible option in patients with inoperable TC and can stabilize the lesion size or even reduce it, leading to a more favorable surgical outcome.

Thyroid Cancers: From Surgery to Current and Future Systemic Therapies through Their Molecular Identities

Differentiated thyroid cancers (DTC) are commonly and successfully treated with total thyroidectomy plus/minus radioiodine therapy (RAI). Medullary thyroid cancer (MTC) is only treated with surgery but only intrathyroidal tumors are cured. The worst prognosis is for anaplastic (ATC) and poorly differentiated thyroid cancer (PDTC). Whenever a local or metastatic advanced disease is present, other treatments are required, varying from local to systemic therapies. In the last decade, the efficacy of the targeted therapies and, in particular, tyrosine kinase inhibitors (TKIs) has been demonstrated. They can prolong the disease progression-free survival and represent the most important therapeutic option for the treatment of advanced and progressive thyroid cancer. Currently, lenvatinib and sorafenib are the approved drugs for the treatment of RAI-refractory DTC and PDTC while advanced MTC can be treated with either cabozantinib or vandetanib. Dabrafenib plus trametinib is the only approved treatment by FDA for BRAFV600E mutated ATC. A new generation of TKIs, specifically for single altered oncogenes, is under evaluation in phase 2 and 3 clinical trials. The aim of this review was to provide an overview of the current and future treatments of thyroid cancer with regards to the advanced and progressive cases that require systemic therapies that are becoming more and more targeted on the molecular identity of the tumor.

Clinicopathological Characteristics and Prognosis of Poorly Differentiated Thyroid Carcinoma Diagnosed According to the Turin Criteria

OBJECTIVE

Poorly differentiated thyroid carcinoma (PDTC) is the primary cause of death in patients with nonanaplastic follicular cell-derived thyroid carcinoma. We purposed to identify the clinical and pathological characteristics of PDTC and their relationship with prognosis.

METHODS

A retrospective analysis was conducted on patients diagnosed with PDTC at our institution from 2010 to 2018. All of their histopathology slides were reviewed by 2 experienced pathologists based on the Turin criteria. Furthermore, information regarding clinical characteristics, pathological characteristics, treatment strategy, and follow-up events were collected. The Kaplan-Meier method was used for survival analysis, while the log-rank test was used to compare survival curves. Then, the Cox proportional hazards model was used to perform univariate and multivariate analyses.

RESULTS

Twenty-six patients with PDTC who met the Turin criteria were enrolled in this study. The median follow-up period of the included 26 patients was 76 months, while the 3- and 5-year survival rates were 40% and 18%, respectively. Notably, univariate analysis revealed that tumor size >4 cm (P = .038), extrathyroidal extension (ETE) (P = .020), distant metastases (P = .047), poorly differentiated areas >60% (P = .049), and Ki-67 labeling index >30% (P = .040) were associated with poor prognosis. On the other hand, multivariate analysis identified ETE (P = .007) and distant metastases (P = .031) as independent risk factors for poor prognosis.

CONCLUSION

PDTC is a rare carcinoma with high invasiveness and poor prognosis. Patients with ETE or distant metastases may have adverse outcomes.

Impact of Gross Strap Muscle Invasion on Outcome of Differentiated Thyroid Cancer: Systematic Review and Meta-Analysis

Background: Gross strap muscle invasion (gSMI) in patients with differentiated thyroid cancer (DTC) was defined as high-risk recurrent group in the 2015 American Thyroid Association guidelines. However, controversy persists because several studies suggested gSMI had little effect on disease outcome. Herein, a systematic review and meta-analysis was conducted to investigate impact of gSMI on outcome of DTC. Methods: A systematic search of electronic databases (PubMed, EMBASE, Cochrane Library, and MEDLINE) for studies published until February 2020 was performed. Case-control studies and randomized controlled trials that studied the impact of gSMI on outcome of DTC were included. Results: Six studies (all retrospective studies) involving 13,639 patients met final inclusion criteria. Compared with no extrathyroidal extension (ETE), patients with gSMI were associated with increased risk of recurrence (P = 0.0004, OR, 1.46; 95% CI: 1.18-1.80) and lymph node metastasis (LNM) (P < 0.00001, OR 4.19; 95% CI: 2.53-6.96). For mortality (P = 0.34, OR 1.47; 95% CI: 0.67-3.25), 10 year disease-specific survival (P = 0.80, OR 0.91; 95% CI: 0.44-1.88), and distant metastasis (DM) (P = 0.21, OR 2.94; 95% CI: 0.54-15.93), there was no significant difference between gSMI and no ETE group. In contrast with maximal ETE(extension of the primary tumor to the trachea, esophagus, recurrent laryngeal nerve, larynx, subcutaneous soft tissue, skin, internal jugular vein, or carotid artery), patients with gSMI were associated with decreased risk of recurrence (P < 0.0001, OR, 0.58; 95% CI: 0.44-0.76), mortality (P = 0.0003, OR 0.20; 95% CI: 0.08-0.48), LNM (P = 0.0003, OR 0.64; 95% CI: 0.50-0.81), and DM (P = 0.0009, OR 0.28; 95% CI: 0.13-0.59). Conclusions : DTC patients with gSMI had a higher risk of recurrence and LNM than those without ETE. However, in contrast with maximal ETE, a much better prognosis was observed in DTC patients with only gSMI.

The revised clinical practice guidelines on the management of thyroid tumors by the Japan Associations of Endocrine Surgeons: Core questions and recommendations for treatments of thyroid cancer

The Japan Associations of Endocrine Surgeons has developed the revised version of the Clinical Practice Guidelines for Thyroid Tumors. This article describes the guidelines translated into English for the 35 clinical questions relevant to the therapeutic management of thyroid cancers. The objective of the guidelines is to improve health-related outcomes in patients with thyroid tumors by enabling users to make their practice evidence-based and by minimizing any variations in clinical practice due to gaps in evidential knowledge among physicians. The guidelines give representative flow-charts on the management of papillary, follicular, medullary, and anaplastic thyroid carcinoma, along with recommendations for clinical questions by presenting evidence on the relevant outcomes including benefits, risks, and health conditions from patients' perspective. Therapeutic actions were recommended or not recommended either strongly (◎◎◎ or XXX) based on good evidence (😊)/good expert consensus (+++), or weakly (◎, ◎◎ or X, XX) based on poor evidence (😣)/poor expert consensus (+ or ++). Only 10 of the 51 recommendations given in the guidelines were supported by good evidence, whereas 35 were supported by good expert consensus. While implementing the current guidelines would be of help to achieve the objective, we need further clinical research to make our shared decision making to be more evidence-based.

Poorly differentiated thyroid carcinoma

Poorly differentiated thyroid carcinoma (PDTC) is an aggressive form of follicular cell derived thyroid carcinoma with a prognosis intermediate between the indolent well differentiated thyroid carcinomas and the rapidly growing often fatal anaplastic carcinoma. While all investigators agree on the presence of this entity, there is disagreement in regard to its definition. In 2006, a set of criteria based solely on mitotic index ≥5/10 high power fields and/or tumor necrosis was proposed by a group of researchers from Memorial Sloan Kettering Cancer Center (MSKCC criteria) in New York. A year later, alternative diagnostic criteria of PDTC, so called the Turin proposal, were advocated by an international consensus group. The Turin proposal requires three criteria: 1) solid/trabecular/insular growth pattern; 2) absence of nuclear features of papillary carcinoma; and 3) at least one of the following three features: mitotic index ≥3/10 high power fields (HPFs), necrosis, or convoluted nuclei. In this review, we summarize the histology, diagnostic criteria (Turin proposal and MSKCC criteria) with their pros and cons, the prognostic factors, and molecular profile of PDTC, aiming to provide a practical and compreshensive review of this challenging entity.

Synergistic effect of clinicopathological factors on mortality risk in patients with differentiated thyroid cancer: An analysis using the SEER database

OBJECTIVES

In this study, we analyzed the effects of histology subtypes, lymph node N-stages, and the presence of extrathyroidal extensions on cancer-specific survival (CSS) and overall survival (OS) in patients with differentiated thyroid cancer.

MATERIALS AND METHODS

Cox proportional hazards regression analyses were carried out to evaluate the correlations between clinicopathological factors and CSS/OS. The combined effects of these factors on CSS and OS were then analyzed to determine the relative excess risk, attributable proportion, and synergy index. Kaplan-Meier curves were used to evaluate the mortality rate.

RESULTS

A total of 86033 cases were included in the analysis. Histology subtype, N-stage, and extrathyroidal extension were all found to be risk factors for CSS (hazard ratio [HR] = 1.8, 95% confidence intervals [CI]: 1.4-2.3, p < 0.001; HR = 1.9, 95% CI: 1.6-2.3, p < 0.001; HR = 1.4, 95% CI: 1.0-1.9, p = 0.035, respectively). The risk factors for OS were histology subtype and N-stage (HR = 1.3, 95% CI; 1.2-1.5, p < 0.001; HR = 1. 4, 95% CI: 1.3-1.5, p < 0.001, respectively) but not extrathyroidal extension (HR = 1.1, 95% CI: 0.9-1.3, p = 0.228). Furthermore, histology subtype and N-stage, histology subtype and extrathyroidal extension, and N stage and extrathyroidal extension (relative excess risk, attributable proportion, and synergy index: 48.8, 0.9, 7.6; 50.2, 0.7, 3.9; 7.0, 0.3, 1.6; respectively) were found to have significant synergistic effects.

CONCLUSION

Patients with follicular thyroid carcinoma (FTC) and extrathyroidal extension or lymph node metastasis are at a higher risk of mortality. Histology subtype, N-stage, and extrathyroidal extension appear to have synergistic effects on the increased risk of poor CSS in patients. This result can in the further development of treatment guidelines to improve the outcome of FTC patients.

Modern surgery for advanced thyroid cancer: a tailored approach

Surgical treatment of advanced thyroid malignancy can be morbid, compromising normal functions of the upper aerodigestive tract. There is a paucity of guidelines dedicated to the management of advanced disease. In fact, there is not even a uniform definition for advanced thyroid cancer currently. The presence of local invasion, bulky cervical nodes, distant metastases or recurrent disease should prompt careful preoperative evaluation and planning. Surgical strategy should evolve from multidisciplinary discussion that integrates individual disease characteristics and patient preference. Intraoperative neuromonitoring has important applications in surgery for advanced disease and should be used to guide surgical strategy and intraoperative decision-making. Recent paradigm shifts, including staged surgery and use of neoadjuvant targeted therapy hold potential for decreasing surgical morbidity and improving clinical outcomes. Modern surgical planning provides optimal treatment for each patient through a tailored approach based on exact extent and type of disease as well as incorporating appreciation of surgical complications, patient preferences and intraoperative findings.

Targeted Therapy for Advanced Thyroid Cancer: Kinase Inhibitors and Beyond

The treatment of advanced thyroid cancer has undergone rapid evolution in the last decade, with multiple kinase inhibitor drug approvals for each subtype of thyroid cancer and a number of other commercially available drugs that have been studied for this indication. Although most of the US Food and Drug Administration (FDA)-approved drugs are antiangiogenic multikinase inhibitors-vandetanib, cabozantinib, sorafenib, lenvatinib-there are two FDA indications that are mutation specific-dabrafenib/trametinib for BRAF-mutated anaplastic thyroid cancer and larotrectinib for NTRK-fusion thyroid cancer. Furthermore, other mutation-specific drugs, immunotherapies, and novel strategies for advanced thyroid cancer are under investigation. Understanding the molecular basis of thyroid cancer, the drugs of interest for treatment of advanced thyroid cancer, and how these drugs can be administered safely and in the appropriate clinical scenario are the topics of this review.

Case report: lenvatinib in neoadjuvant setting in a patient affected by invasive poorly differentiated thyroid carcinoma

We report a case of an elderly woman presenting with a huge cervical mass invading the tracheal lumen. Diagnosed as invasive poorly differentiated thyroid cancer, after an endotracheal biopsy, stenting and radiotherapy, it was judged eligible for total thyroidectomy, but surgery was delayed due to pulmonary thromboembolism. The patient was therefore treated with lenvatinib with a neoadjuvant intent until hemodynamic stability was obtained. Thyroidectomy and radioiodine therapy were then performed and the postdose scan revealed an area of modest uptake in the anterior part of the neck. The patient is now in a good clinical status and she continues her follow-up program without any adjuvant therapy.

An algorithmic approach to overcome diagnostic challenges in FNAC in large-cell poorly differentiated thyroid carcinomas

INTRODUCTION

Poorly differentiated thyroid carcinoma (PDTC) is a distinct entity and a rare carcinoma of thyroid follicular origin with an intermediate prognosis. It is defined by the Turin criteria set in 2007. Although this entity is well known, with widely available literature on histological features, specific studies describing the cytological features of PDTC (especially the large cell type) are lacking. In this study, we describe the cytological and clinical features of PDTC showing large cells (PDTC-LC) with abundant cytoplasm.

MATERIALS

Twelve cases of PDTC showing abundant cytoplasm between 2007 and 2016 were retrieved from the departmental archives and studied.

RESULTS

The cases occurred predominantly in women with a mean age of 54.3 years. The mean tumor size was 4.3 cm. Fine-needle aspiration cytology (FNAC) smears showed singly scattered large cells with abundance of cytoplasm admixed with microfollicular and insular pattern. Lymph node metastasis was noted in 7 cases and distant metastasis to bone and visceral organs were also seen in 7 cases.

CONCLUSIONS

Microfollicular pattern may lead to these cases being misinterpreted as a differentiated follicular neoplasm on FNAC, and the dissociated large cells may mimic Hürthle cell neoplasm. Immunocytochemistry is not helpful in this scenario, although it does resolve the diagnostic dilemma when the differential diagnoses include medullary thyroid carcinoma and metastatic tumors. It is important to identify these tumors on FNAC as this facilitates proper management.

Clinicopathological and Survival Outcomes of Well-Differentiated Thyroid Carcinoma Undergoing Dedifferentiation: A Retrospective Study from FUSCC

BACKGROUND

Recently, several studies have reported that dedifferentiation occurs in fatal well-differentiated thyroid cancer (WDTC) cases. This study aimed at investigating the clinicopathological characteristics of WDTC undergoing dedifferentiation.

METHODS

A total of 63 WDTC patients harboring dedifferentiated phenotype were enrolled in the study. The Kaplan-Meier method and Cox regression analysis were used to perform survival analyses. Harrell index of concordance (C-index) and Akaike information criterion (AIC) were calculated to compare the predictive value for prognosis among several prognostic classification systems.

RESULTS

The median cause-specific survival (CSS) of patients was 138 months, with the CSS rate of 64.0% and 53.3% at 5 and 10 years, respectively. Presence of the anaplastic thyroid cancer (ATC) phenotype significantly increased the risk of poor CSS (P = 0.033), and age was the only independent risk factor for disease progression (P = 0.015). The C-index and AIC of the age, grade, extent, size (AGES) prognostic classification system for the CSS were 0.723 and 59.937, respectively.

CONCLUSIONS

The presence of dedifferentiated phenotypes can be responsible for the poor outcomes in WDTC patients. The AGES system demonstrates to be an optimal prognostic system for WDTC undergoing dedifferentiation.

Application of intensity-modulated radiotherapy in unresectable poorly differentiated thyroid carcinoma

Poorly differentiated thyroid carcinoma (PDTC) is a rare and aggressive malignancy with high rates of invasion and distant metastasis. This study was to explore the ability of intensity-modulated radiotherapy (IMRT) combined with chemotherapy to manage unresectable PDTC. Between February 2011 and April 2012, 5 patients with unresectable PDTC were treated by IMRT at our institution and were included in this analysis. The median radiotherapy dose to the gross tumor volume (GTV) was 66 Gy/33 fractions/6.4 weeks. All patients received chemotherapy, and one patient with tumor compression symptoms had a tracheotomy before treatment. The mean survival time of the 5 patients was 41.6 months. The direct causes of death were distant metastases (40%) and progression of the locoregional disease (20%). In conclusion, IMRT combined with chemotherapy for unresectable PDTC might be beneficial to improve locoregional control. Further new therapies are needed to control metastases.

Dual Inhibition of HDAC and Tyrosine Kinase Signaling Pathways with CUDC-907 Inhibits Thyroid Cancer Growth and Metastases

Purpose: There is currently no standard therapy for anaplastic thyroid cancer (ATC) and poorly differentiated thyroid cancer (PDTC), which account for two-thirds of thyroid cancer-related deaths. Driver mutations in the PI3K/AKT and RAF/RAS/MEK/ERK pathways are common in ATC and PDTC. Histone deacetylases (HDAC) regulate cancer initiation and progression. Our aim was to determine the therapeutic efficacy of simultaneously targeting these pathways in thyroid cancer with a single agent and to evaluate biomarkers of treatment response.Experimental Design: CUDC-907 is a first-in-class compound, functioning as a dual inhibitor of HDACs and the PI3K/AKT pathway. We investigated its antiproliferative effect in vitro and in vivoResults: CUDC-907 significantly inhibited cellular proliferation in thyroid cancer cell lines, induced G₂-M arrest with decreased levels of the checkpoint regulators cyclin B1, AURKA, AURKB, PLK1, and increased p21 and p27. Treatment induced apoptosis with increased caspase-3/7 activity and decreased survivin levels and decreased cellular migration and invasion. CUDC-907 treatment caused H3 hyperacetylation and decreased HDAC2 expression. HDAC2 was upregulated in ATC and other thyroid cancer histologic subtypes. CUDC-907 treatment reduced both p-AKT and p-ERK1/2 levels. Finally, CUDC-907 treatment, in a metastatic mouse model of thyroid cancer, showed significant inhibition of growth and metastases, and tumors from treated mice had decreased HDAC2 expression, suggesting that this may be a useful biomarker of response.Conclusions: Dual inhibition of HDAC and the tyrosine kinase signaling pathways with CUDC-907 is a promising treatment strategy for advanced, metastatic thyroid cancer. Clin Cancer Res; 23(17); 5044-54. ©2017 AACR.

Extrathyroidal Extension Is Associated with Compromised Survival in Patients with Thyroid Cancer

BACKGROUND

Patients with thyroid cancer who have extrathyroidal extension (ETE) are considered to have more advanced tumors. However, data on the impact of ETE on patient outcomes remain limited. The purpose of this study was to evaluate the association between ETE and survival in patients with thyroid cancer.

METHODS

The National Cancer Database (1998-2012) was queried for all adult patients with differentiated thyroid cancer and medullary thyroid cancer. Patients were divided into three groups: no ETE (T1 and T2 tumors), minimal ETE (T3 tumors <4 cm), and extensive ETE (T4 tumors <4 cm). Patient demographic, clinical, and pathologic factors were evaluated for all patients. A Cox proportional hazards model was developed for each histology to identify factors associated with survival.

RESULTS

In total, 241,118 patients with differentiated thyroid cancer met the inclusion criteria; 86.9% had no ETE, 9.1% minimal ETE, and 4.0% extensive ETE. Compared with patients with no ETE, patients with minimal and extensive ETE were more likely to have larger tumors (1.4 cm vs. 1.8 cm and 2.0 cm, respectively), lymphovascular invasion (8.6% vs. 28.0% and 35.1%, respectively), positive margins after thyroidectomy (6.1% vs. 35.2% and 45.9%, respectively), and regional lymph node metastases (32.5% vs. 67.0% and 74.6%, respectively; all p < 0.01). After adjustment, minimal ETE (hazard ratio [HR] = 1.13; p < 0.01) and extensive ETE (HR = 1.74; p < 0.01) were associated with compromised survival for patients with differentiated thyroid cancer. In total, 3415 patients with medullary thyroid cancer met the inclusion criteria; 87.9% had no ETE, 7.1% minimal ETE, and 5.0% extensive ETE. Compared with patients with no ETE, patients with minimal and extensive ETE were more likely to have larger tumors (1.7 cm vs. 2.2 cm and 2.2 cm, respectively), lymphovascular invasion (19.2% vs. 68.9% and 79.3%, respectively), positive margins after thyroidectomy (5.8% vs. 44.1% and 51.9%, respectively), and regional lymph node metastases (39.0% vs. 90.5% and 94.4%, respectively; all p < 0.01). After adjustment, extensive ETE (HR = 1.63; p = 0.01) was associated with compromised survival for patients with medullary thyroid cancer.

CONCLUSION

In patients with differentiated and medullary thyroid cancers, ETE is associated with compromised survival. Given these findings, ETE should be included in the thyroid cancer treatment guidelines.

Recurrence and Survival After Gross Total Removal of Resectable Undifferentiated or Poorly Differentiated Thyroid Carcinoma

BACKGROUND

This study aimed to evaluate the recurrence and survival after initial curative-intent surgery of resectable anaplastic thyroid cancer (ATC) and poorly differentiated thyroid cancer (PDTC).

METHODS

A retrospective analysis was conducted on patients with ATC and PDTC who had been treated between 1985 and 2013. Among them, 119 patients who had undergone surgery with curative intent were included in this study. The outcome measures included the clinical response to treatment and the recurrence rates of three separate thyroid cancer groups: ATC, differentiated thyroid cancer (DTC) with anaplastic foci, and PDTC.

RESULTS

Initial remission was achieved in 100 (84.0%) patients, with higher percentages in patients with DTC with anaplastic foci (97.8%) and PDTC (96.7%) compared with ATC (60.5%). The overall recurrence rate after initial remission was 30.8% in ATC, 25.9% in PDTC, and 6.7% in DTC with anaplastic foci. Pathologic diagnosis, preexisting goiter or tumors, along with tracheal and lymphatic/vascular invasion were correlated with recurrence (p < 0.001; p = 0.001, 0.006, 0.003, and 0.016, respectively). All patients without initial remission died due to local failure, and most patients with recurrence, apart from two PDTC patients, had distant metastasis. Overall mortality after initial curative-intent surgery was 58.1% in ATC, 8.7% in DTC with anaplastic foci, and 20% in PDTC.

CONCLUSIONS

The initial remission of resectable tumors was higher and the recurrence rate was lower in DTC with anaplastic foci and PDTC compared with ATC. Careful monitoring of the development of distant metastasis is necessary, especially in patients with aggressive pathology with tracheal and lymphovascular invasion.

Changes of Clinicopathologic Characteristics and Survival Outcomes of Anaplastic and Poorly Differentiated Thyroid Carcinoma

BACKGROUND

This study aimed to analyze the temporal changes of the clinicopathologic characteristics, and the long-term outcomes, of various types of anaplastic thyroid cancer (ATC) and poorly differentiated thyroid cancer (PDTC).

METHODS

A retrospective analysis was conducted on patients with ATC and PDTC who were treated from 1985 to 2013. The outcome measures included the clinical response to treatment and the survival rates of three separate thyroid cancer groups: ATC, PDTC, and differentiated thyroid cancer (DTC) with anaplastic foci.

RESULTS

The five-year disease-specific survival rate was significantly higher, both in DTC with anaplastic foci and in PTDC (81.3% and 65.8%, respectively), than it was in ATC (14.3%; p < 0.001). The proportion of cases of DTC with anaplastic foci has been increasing over time, while that of ATC has decreased. The survival rate was found to be significantly higher in resectable tumors (71.4% and 26.5%, respectively; p < 0 .001). In ATC, external beam radiation therapy showed longer survival rates than did surgery-based treatment in unresectable tumors (19.2 vs. 7.7 months, p = 0.006). Adjuvant treatment with external beam radiation or radioactive iodine increased survival duration in PDTC and in DTC with anaplastic foci. Lymphatic invasion was the most significant postoperative prognosticator in ATC (p = 0.013).

CONCLUSIONS

The choice of treatment of ATC and PDTC could be modified according to resectability and lymphatic invasion of the cancer.

Pediatric Differentiated Thyroid Carcinoma of Follicular Cell Origin: Prognostic Significance of Histologic Subtypes

BACKGROUND

Thyroid cancers are rare in the pediatric age group, and unlike in adults, few data are available regarding the clinical implication of histologic subtypes in the pediatric population. The purpose of the current study was to determine the prognostic significance of histologic subtypes of differentiated thyroid cancer (DTC) in a large series of children and adolescents followed at a single institution.

METHODS

A retrospective review was conducted of all pediatric DTC patients who were treated and followed between 1988 and 2012. Sixty-two patients (median age at diagnosis 13.8 years, median age at follow-up 18 years, 77% female) were assessed. The most common subtypes included classic papillary thyroid carcinoma (PTC; 48%), diffuse sclerosing PTC (16%), and follicular variant PTC (15%); 37% were considered "high-risk" histologies based on adult criteria.

RESULTS

In a multivariate model, only extensive extrathyroidal extension (ETE), defined as the presence of two or more microscopic foci of tumor cells ≤1 mm in size each or any foci >1 mm in size invading beyond the thyroid capsule into perithyroid soft tissue or organs, was significantly associated with extent of disease at presentation. At last follow-up, 76% of subjects had no evidence of disease, 18% had persistent disease, and 5% had recurrent/progressive disease. Event-free survival was associated with extent of disease at presentation (p = 0.01), extensive ETE at diagnosis (p < 0.01), and male sex (p = 0.01), but not histologic subtype (p = 0.20).

CONCLUSIONS

Pediatric DTC carries an excellent prognosis. Extensive ETE at diagnosis was found to be an independent predictor of extent of disease at presentation, as well as event-free survival. Unlike in the adult population, "high-risk" histologic subtypes did not independently predict extent of disease at presentation or event-free survival in this pediatric population with DTC.

Follicular cell-derived thyroid cancer

Follicular cell-derived thyroid cancers are derived from the follicular cells in the thyroid gland, which secrete the iodine-containing thyroid hormones. Follicular cell-derived thyroid cancers can be classified into papillary thyroid cancer (80-85%), follicular thyroid cancer (10-15%), poorly differentiated thyroid cancer (<2%) and undifferentiated (anaplastic) thyroid cancer (<2%), and these have an excellent prognosis with the exception of undifferentiated thyroid cancer. The advent and expansion of advanced diagnostic techniques has driven and continues to drive the epidemic of occult papillary thyroid cancer, owing to overdiagnosis of clinically irrelevant nodules. This transformation of the thyroid cancer landscape at molecular and clinical levels calls for the modification of management strategies towards personalized medicine based on individual risk assessment to deliver the most effective but least aggressive treatment. In thyroid cancer surgery, for instance, injuries to structures outside the thyroid gland, such as the recurrent laryngeal nerve in 2-5% of surgeries or the parathyroid glands in 5-10% of surgeries, negatively affect quality of life more than loss of the expendable thyroid gland. Furthermore, the risks associated with radioiodine ablation may outweigh the risks of persistent or recurrent disease and disease-specific mortality. Improvement in the health-related quality of life of survivors of follicular cell-derived thyroid cancer, which is decreased despite the generally favourable outcome, hinges on early tumour detection and minimization of treatment-related sequelae. Future opportunities include more widespread adoption of molecular and clinical risk stratification and identification of actionable targets for individualized therapies.

Neoadjuvant chemotherapy in 13 patients with locally advanced poorly differentiated thyroid carcinoma based on Turin proposal - a single institution experience

BACKGROUND

There is a paradigm that chemotherapy is ineffective in thyroid carcinoma. The aim of our study was to find out whether neoadjuvant chemotherapy before thyroid surgery had an effect on the size of primary tumour in patients with poorly differentiated thyroid carcinoma (PDTC) based on Turin proposal.

PATIENTS AND METHODS

Altogether, 13 patients (8 women, 5 men; median age 61 years) with PDTC based on Turin proposal were treated with neoadjuvant chemotherapy between 1986 and 2005. Tumour diameter was from 4.5 to 18 cm (median 9 cm). Regional and distant metastases were detected in 6 and 9 patients, respectively. Eight patients had pT4 tumour.

RESULTS

Altogether, 29 (range 1-5) cycles of chemotherapy were given. Tumour diameter decreased in all the patients and by more than 30% in 5 patients (= 38%). Two of these five patients had also preoperative external beam irradiation (EBRT). Total thyroidectomy, lobectomy and neck dissection were performed in 10, 3 and 5 cases, respectively. R0 and R1 resection was done in 5 and 8 cases, respectively. Eight patients had postoperative EBRT of the neck and upper mediastinum. The 5-year and 10-year cause-specific survival rates of patients were 66% and 20%, respectively.

CONCLUSIONS

After neoadjuvant chemotherapy a partial tumour regression was observed in 38% of patients with PDTC based on Turin proposal.

Thyroid circadian timing: roles in physiology and thyroid malignancies

The circadian clock represents an anticipatory mechanism, well preserved in evolution. It has a critical impact on most aspects of the physiology of light-sensitive organisms. These rhythmic processes are governed by environmental cues (fluctuations in light intensity and temperature), an internal circadian timing system, and interactions between this timekeeping system and environmental signals. Endocrine body rhythms, including hypothalamic-pituitary-thyroid (HPT) axis rhythms, are tightly regulated by the circadian system. Although the circadian profiles of thyroid-releasing hormone (TRH), thyroid-stimulating hormone (TSH), thyroxine (T4), and triiodothyronine (T3) in blood have been well described, relatively few studies have analyzed molecular mechanisms governing the circadian regulation of HPT axis function. In this review, we will discuss the latest findings in the area of complex regulation of thyroid gland function by the circadian oscillator. We will also highlight the molecular makeup of the human thyroid oscillator as well as the potential link between thyroid malignant transformation and alterations in the clockwork.

Poorly differentiated thyroid cancer

PURPOSE OF REVIEW

Poorly differentiated thyroid carcinomas (PDTCs) comprise a small subset of heterogeneous thyroid tumors, occupying an intermediate area between well differentiated follicular or papillary carcinoma and anaplastic carcinomas, from both a histopathogenetic and a clinical point of view. PDTCs are more aggressive than the well differentiated, but less aggressive than the anaplastic thyroid cancers. They have a distinct biological behavior, and the classification of these tumors into a separate group appears justified.

RECENT FINDINGS

The criteria used to diagnose PDTC have been an area of controversy. The multiple definitions of PDTC make the literature difficult to interpret. No clinical features can accurately diagnose PDTCs. Thus, the results of histocytology, immunohistochemistry, and molecular genetics tests aid in diagnosis. Given the aggressiveness of PDTCs, with increased recurrence and decreased survival rates, a multimodality treatment approach is required.

SUMMARY

We conducted a comprehensive review of the current diagnostic and therapeutic tools in the management of patients with PDTCs. The present article aims to review the various aspects of this tumor type, from morphology to immunohistochemistry, and molecular abnormalities from a practical and daily practice-oriented point of view.

Obatoclax overcomes resistance to cell death in aggressive thyroid carcinomas by countering Bcl2a1 and Mcl1 overexpression

Poorly differentiated tumors of the thyroid gland (PDTC) are generally characterized by a poor prognosis due to their resistance to available therapeutic approaches. The relative rarity of these tumors is a major obstacle to our understanding of the molecular mechanisms leading to tumor aggressiveness and drug resistance, and consequently to the development of novel therapies. By simultaneously activating Kras and deleting p53 (Trp53) in thyroid follicular cells, we have generated a novel mouse model that develops papillary thyroid cancer invariably progressing to PDTC. In several cases, tumors further progress to anaplastic carcinomas. The poorly differentiated tumors are morphologically and functionally similar to their human counterparts and depend on MEK/ERK signaling for proliferation. Using primary carcinomas as well as carcinoma-derived cell lines, we also demonstrate that these tumors are intrinsically resistant to apoptosis due to high levels of expression of the Bcl2 family members, Bcl2a1 (Bcl2a1a) and Mcl1, and can be effectively targeted by Obatoclax, a small-molecule pan-inhibitor of the Bcl2 family. Furthermore, we show that Bcl2 family inhibition synergizes with MEK inhibition as well as with doxorubicin in inducing cell death. Thus, our studies in a novel, relevant mouse model have uncovered a promising druggable feature of aggressive thyroid cancers.

Poorly differentiated thyroid carcinoma with sternal invasion. A case report and review of the literature

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Only 4 cases of concomitant thyroidectomy and sternal resection and reconstruction have been reported.

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We report a 66-year-old female with a poorly differentiated thyroid carcinoma and direct sternal invasion who underwent total thyroidectomy and partial sternal resection and chest wall reconstruction.

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In previous case reports the sternal tumor was not in continuity with the thyroid tumor.

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Despite developing an early local recurrence, there was no clinical or radiographic evidence of recurrent disease 5-years postoperatively.

INTRODUCTION

Surgical resection of poorly differentiated thyroid carcinoma with direct invasion of the sternum has not been previously reported. Only 4 cases of concomitant thyroidectomy and sternal resection and reconstruction for sternal metastases have been published.

PRESENTATION OF CASE

A 66-year-old female with a poorly differentiated thyroid carcinoma and direct sternal invasion underwent total thyroidectomy and resection of the manubrium and both clavicular heads, and chest wall reconstruction with polypropylene mesh and bilateral myocutaneous pectoralis major muscle flaps. Postoperatively, the patient received radioactive iodine ablation. She developed a local recurrence, requiring additional ablation with radioactive iodine and external beam radiation therapy. Although there was no clinical or radiographic evidence of recurrent disease 5-years postoperatively, a possible local recurrence was discovered 4 months later.

DISCUSSION

In previous case reports the sternal metastases were not in continuity with the thyroid tumor. In our patient, however, there was evidence of direct extension between the thyroid tumor and the sternal mass that were connected together with cords of tumor.

CONCLUSION

In our patient with poorly differentiated thyroid carcinoma invading the sternum, total thyroidectomy and resection of the manubrium with sternal reconstruction, combined with adjuvant radioactive iodine ablation and external beam radiation therapy was associated with prolonged survival after 5 years despite a small local recurrence.