Current understanding and management of medullary thyroid cancer

Correlation of 18F-sodium fluoride uptake and radiodensity in extraosseous metastases of medullary thyroid carcinoma

Objective

Although 18F-sodium fluoride (18F-NaF) uptake is frequently observed in extraosseous metastases of medullary thyroid carcinoma (MTC) with calcification, itcan also occur in metastatic sites without visible calcium deposition, leading to the hypothesis that visually undetectable calcium accumulation may be responsible for this uptake. The aim of this study was to indirectly support this hypothesis by analyzing the correlation between the degree of 18F-NaF uptake and radiodensity in extraosseous MTC metastases, since calcium deposition can increase attenuation even when not visually detectable.

Subjects and methods

Extraosseous metastatic lesions of 15 patients with MTC were evaluated using 18F-NaF positron-emission tomography (PET)/computed tomography (CT)and segmented by levels of standardized uptake value (SUV). The correlation between mean SUV and mean Hounsfield unit (HU) values was assessed for the entire group of segments and for two subgroups with different mean HU values.

Results

Very high correlations were observed between mean SUV and mean HU values for both the entire group of segments and the subgroup with a mean HU value greater than 130 (p = 0.92 and p = 0.95, respectively; p < 0.01). High correlation (p = 0.71) was also observed in the subgroup with mean HU values ranging from 20 to 130 (p < 0.01).

Conclusion

The findings of the present study suggest that there is an association between 18F-NaF uptake and calcium deposition in extraosseous metastasesof MTC, supporting the hypothesis that visually undetectable calcium accumulation may be responsible for 18F-NaF uptake in regions without visible calcium deposition.

Unlocking the potential of oncology biomarkers: advancements in clinical theranostics

INTRODUCTION

Cancer biomarkers have revolutionized the field of oncology by providing valuable insights into tumor changes and aiding in screening, diagnosis, prognosis, treatment prediction, and risk assessment. The emergence of "omic" technologies has enabled biomarkers to become reliable and accurate predictors of outcomes during cancer treatment.

CONTENT

In this review, we highlight the clinical utility of biomarkers in cancer identification and motivate researchers to establish a personalized/precision approach in oncology. By extending a multidisciplinary technology-based approach, biomarkers offer an alternative to traditional techniques, fulfilling the goal of cancer therapeutics to find a needle in a haystack.

SUMMARY AND OUTLOOK

We target different forms of cancer to establish a dynamic role of biomarkers in understanding the spectrum of malignancies and their biochemical and molecular characterization, emphasizing their prospective contribution to cancer screening. Biomarkers offer a promising avenue for the early detection of human cancers and the exploration of novel technologies to predict disease severity, facilitating maximum survival and minimum mortality rates. This review provides a comprehensive overview of the potential of biomarkers in oncology and highlights their prospects in advancing cancer diagnosis and treatment.

Improved Adherence to ATA Medullary Thyroid Cancer Treatment Guidelines

BACKGROUND

The 2009 American Thyroid Association (ATA) guidelines for medullary thyroid cancer (MTC) were created to unify national practice patterns. Our aims were to (1) evaluate national adherence to ATA guidelines before and after 2009, (2) identify factors that are associated with concordance with guidelines, and (3) evaluate whether there is an association between survival and concordant treatment.

PATIENTS AND METHODS

Patients with MTC were identified from the 2009 to 2015 National Cancer Database. Adherence to ATA recommendations regarding extent of surgery (R61-R66) was analyzed. Logistic regression was used to determine predictors of discordance and propensity score matching was used to compare concordant treatment rates between time periods. Kaplan-Meier survival analysis was used to determine association between survival and concordant treatment.

RESULTS

There were 3421 patients with MTC, and of these 3087 had M0 disease and 334 had M1 disease. We found that 72% of M0 cases adhered to R61-66, and 68% of M0 cases without advanced local disease were adherent to R61-63. Following propensity score matching, the adherence rate was 67% before 2009 and 74% after. Patient factors associated with discordant treatment were female gender, older age, treatment at a nonacademic facility, and living within 50 miles of the treatment facility. Adherence to guidelines was associated with improved overall survival (OS) (p < 0.01).

CONCLUSIONS

Treatment of MTC was discordant from guidelines in 26% of cases from 2009 to 2015 compared with 33% prior to 2009 in a propensity matched analysis, and was most often in cases with localized, noninvasive disease. Improved adherence to guidelines may improve overall survival.

Management of neuroendocrine tumor liver metastases

BACKGROUND

Neuroendocrine Tumors (NETs) are a group of tumors that arise from neuroendocrine cells, and are increasing in incidence worldwide. These tumors often metastasize to the liver, and management of these neuroendocrine tumor liver metastases (NELMs) requires a multi-disciplinary approach. We aim to provide a comprehensive update for treatment of NELMs.

METHODS

We completed a comprehensive systemic review of papers involving the diagnosis, treatment, and outcomes of NELMs. We identified 1612 records via Scopus database literature search. Two independent authors reviewed these records, with 318 meeting criteria for inclusion in the final systemic review.

RESULTS

Primary tumor resection with resection of liver metastases is the treatment of choice for patients with NELMs. Liver-directed therapies and liver transplantation can be considered for patients with unresectable liver metastases. Systemic medical therapy is used for managing tumor burden and symptoms caused by NELMs.

CONCLUSIONS

Advancement in liver-directed and targeted systemic therapies provide improved options for patients with unresectable tumors. Given the complexity of NELMs, management of NELMs necessitates multidisciplinary teams at comprehensive health centers.

Challenges in the care of patients with RET-altered thyroid cancer: a multicountry mixed-methods study

BACKGROUND

The discovery of driver oncogenes for thyroid carcinomas and the identification of genomically targeted therapies to inhibit those oncogenes have altered the treatment algorithm in thyroid cancer (TC), while germline testing for RET mutations has become indicated for patients with a family history of RET gene mutations or hereditary medullary TC (MTC). In the context of an increasing number of selective RET inhibitors approved for use, this paper aims to describe challenges and barriers affecting providers' ability to deliver optimal care for patients with RET-altered TC across the patient healthcare journey.

METHODS

A mixed-method educational and behavioral needs assessment was conducted in Germany (GER), Japan (JPN), the United Kingdom (UK), and the United States (US) prior to RET-selective inhibitor approval. Participants included medical oncologists (MO), endocrinologists (EN) and clinical pathologists (CP) caring for patients affected with TC. Data collection tools were implemented in three languages (English, German, Japanese). Qualitative data were coded and thematically analyzed in NVivo. Quantitative data were analyzed via frequency and crosstabulations in SPSS. The findings presented here were part of a broader study that also investigated lung cancer challenges and included pulmonologists.

RESULTS

A total of 44 interviews and 378 surveys were completed. Suboptimal knowledge and skills were self-identified among providers, affecting (1) assessment of genetic risk factors (56%, 159/285 of MOs and ENs), (2) selection of appropriate genetic biomarkers (59%, 53/90 of CPs), (3) treatment plan initiation (65%, 173/275 of MOs and ENs), (4) management of side effects associated with multitargeted tyrosine kinase inhibitors (78%, 116/149 of MOs and ENs), and (5) transfer of patients into palliative care services (58%, 160/274 of MOs and ENs). Interviews underscored the presence of systemic barriers affecting the use of RET molecular tests and selective inhibitors, in addition to suboptimal knowledge and skills necessary to manage the safety and efficacy of targeted therapies.

CONCLUSION

This study describes concrete educational needs for providers involved in the care of patients with RET-altered thyroid carcinomas. Findings can be used to inform the design of evidence-based education and performance improvement interventions in the field and support integration into practice of newly approved RET-selective inhibitors.

Genetically engineered mouse models of head and neck cancers

The head and neck region is one of the anatomic sites commonly afflicted by cancer, with ~1.5 million new diagnoses reported worldwide in 2020 alone. Remarkable progress has been made in understanding the underlying disease mechanisms, personalizing care based on each tumor's individual molecular characteristics, and even therapeutically exploiting the inherent vulnerabilities of these neoplasms. In this regard, genetically engineered mouse models (GEMMs) have played an instrumental role. While progress in the development of GEMMs has been slower than in other major cancer types, several GEMMs are now available that recapitulate most of the heterogeneous characteristics of head and neck cancers such as the tumor microenvironment. Different approaches have been employed in GEMM development and implementation, though each can generally recapitulate only certain disease aspects. As a result, appropriate model selection is essential for addressing specific research questions. In this review, we present an overview of all currently available head and neck cancer GEMMs, encompassing models for head and neck squamous cell carcinoma, nasopharyngeal carcinoma, and salivary and thyroid gland carcinomas.

Clinical characteristics, treatment, and long-term outcome of patients with brain metastases from thyroid cancer

Brain metastases (BM) in patients with thyroid cancer (TC) are rare with an incidence of 1% for papillary and follicular, 3% for medullary and up to 10% for anaplastic TC (PTC, FTC, MTC and ATC). Little is known about the characteristics and management of BM from TC. Thus, we retrospectively analyzed patients with histologically verified TC and radiologically verified BM identified from the Vienna Brain Metastasis Registry. A total of 20/6074 patients included in the database since 1986 had BM from TC and 13/20 were female. Ten patients had FTC, 8 PTC, one MTC and one ATC. The median age at diagnosis of BM was 68 years. All but one had symptomatic BM and 13/20 patients had a singular BM. Synchronous BM at primary diagnosis were found in 6 patients, while the median time to BM diagnosis was 13 years for PTC (range 1.9-24), 4 years for FTC (range 2.1-41) and 22 years for the MTC patient. The overall survival from diagnosis of BM was 13 months for PTC (range 1.8-57), 26 months for FTC (range 3.9-188), 12 years for the MTC and 3 months for the ATC patient. In conclusion, development of BM from TC is exceedingly rare and the most common presentation is a symptomatic single lesion. While BM generally constitute a poor prognostic factor, individual patients experience long-term survival following local therapy.

Voltage-Gated Sodium Channel NaV1.7 Inhibitors with Potent Anticancer Activities in Medullary Thyroid Cancer Cells

Our results from quantitative RT-PCR, Western blotting, immunohistochemistry, and the tissue microarray of medullary thyroid cancer (MTC) cell lines and patient specimens confirm that VGSC subtype NaV1.7 is uniquely expressed in aggressive MTC and not expressed in normal thyroid cells and tissues. We establish the druggability of NaV1.7 in MTC by identifying a novel inhibitor (SV188) and investigate its mode of binding and ability to inhibit INa current in NaV1.7. The whole-cell patch-clamp studies of the SV188 in the NaV1.7 channels expressed in HEK-293 cells show that SV188 inhibited the INa current in NaV1.7 with an IC50 value of 3.6 µM by a voltage- and use-dependent blockade mechanism, and the maximum inhibitory effect is observed when the channel is open. SV188 inhibited the viability of MTC cell lines, MZ-CRC-1 and TT, with IC50 values of 8.47 μM and 9.32 μM, respectively, and significantly inhibited the invasion of MZ-CRC-1 cells by 35% and 52% at 3 μM and 6 μM, respectively. In contrast, SV188 had no effect on the invasion of TT cells derived from primary tumor, which have lower basal expression of NaV1.7. In addition, SV188 at 3 μM significantly inhibited the migration of MZ-CRC-1 and TT cells by 27% and 57%, respectively.

An unusual cause of chronic diarrhea in a Middle-Aged adult: A diagnostic challenge

Diarrhea is a common symptom in medical practice that often gets overlooked. This article is intended to increase the awareness of physicians and other providers on a subtle but important cause of chronic diarrhea.

[111In]In-CP04 as a novel cholecystokinin-2 receptor ligand with theranostic potential in patients with progressive or metastatic medullary thyroid cancer: final results of a GRAN-T-MTC Phase I clinical trial

INTRODUCTION

Medullary thyroid cancer (MTC) is a rare malignant tumour of the parafollicular C-cells with an unpredictable clinical course and currently suboptimal diagnostic and therapeutic options, in particular in advanced disease. Overexpression of cholecystokinin-2 receptors (CCK2R) represents a promising avenue to diagnostic imaging and targeted therapy, ideally through a theranostic approach.

MATERIALS AND METHODS

A translational study (GRAN-T-MTC) conducted through a Phase I multicentre clinical trial of the indium-111 labelled CP04 ([¹¹¹In]In-CP04), a CCK2R-seeking ligand was initiated with the goal of developing a theranostic compound. Patients with proven advanced/metastatic MTC or short calcitonin doubling time were enrolled. A two-step concept was developed through the use of low- and high-peptide mass (10 and 50 μg, respectively) for safety assessment, with the higher peptide mass considered appropriate for therapeutic application. Gelofusine was co-infused in a randomized fashion in the second step for the evaluation of potential reduction of the absorbed dose to the kidneys. Imaging for the purpose of biodistribution, dosimetry evaluation, and diagnostic assessment were performed as well as pre-, peri-, and postprocedural clinical and biochemical assessment.

RESULTS

Sixteen patients were enrolled. No serious adverse events after application of the compound at both peptide amounts were witnessed; transient tachycardia and flushing were observed in two patients. No changes in biochemistry and clinical status were observed on follow-up. Preliminary dosimetry assessment revealed the highest dose to urinary bladder, followed by the kidneys and stomach wall. The effective dose for 200 MBq of [¹¹¹In]In-CP04 was estimated at 7±3 mSv and 7±1 mSv for 10 μg and 50 μg CP04, respectively. Administration of Gelofusine reduced the dose to the kidneys by 53%, resulting in the organ absorbed dose of 0.044±0.019 mSv/MBq. Projected absorbed dose to the kidneys with the use of [¹⁷⁷Lu]Lu-CP04 was estimated at 0.9±0.4 Gy/7.4 GBq. [¹¹¹In]In-CP04 scintigraphy was positive in 13 patients (detection rate of 81%) with superior diagnostic performance over conventional imaging.

CONCLUSION

In the present study, [¹¹¹In]In-CP04 was shown to be a safe and effective radiopharmaceutical with promising theranostic characteristics for patients with advanced MTC.

Immunotherapy of Neuroendocrine Neoplasms: Any Role for the Chimeric Antigen Receptor T Cells?

Simple Summary

Neuroendocrine neoplasms (NENs) comprise a heterogeneous group of tumors arising in different organs whose clinical course is variable according to histological differentiation and metastatic spread. Therapeutic options have recently expanded, but there is a need for new effective therapies, especially in less differentiated forms. Chimeric antigen receptor T cells (CAR-T) have shown efficacy in several cancers, mainly hematological, but data on NENs are scattered. We aimed to analyze the available preclinical and clinical data about CAR-T in NENs, to highlight their potential role in clinical practice. A significant therapeutic effect of CAR-T cells in NENs emerges from preclinical studies. Results from clinical trials are expected in order to define their effective role in these cancers.

Abstract

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors with variable clinical presentation and prognosis. Surgery, when feasible, is the most effective and often curative treatment. However, NENs are frequently locally advanced or already metastatic at diagnosis. Consequently, additional local or systemic therapeutic approaches are required. Immunotherapy, based on chimeric antigen receptor T cells (CAR-T), is showing impressive results in several cancer treatments. The aim of this narrative review is to analyze the available data about the use of CAR-T in NENs, including studies in both preclinical and clinical settings. We performed an extensive search for relevant data sources, comprising full-published articles, abstracts from international meetings, and worldwide registered clinical trials. Preclinical studies performed on both cell lines and animal models indicate a significant therapeutic effect of CAR-T cells in NENs. Ongoing and future clinical trials will clarify the possible role of these drugs in patients with highly aggressive NENs.

An Appraisal and Update of Fluorodeoxyglucose and Non-Fluorodeoxyglucose-PET Tracers in Thyroid and Non-Thyroid Endocrine Neoplasms

Endocrine neoplasms and malignancies are a diverse group of tumors with varied clinical, histopathologic, and functional features. These tumors vary from sporadic to hereditary, isolated entities to multiple neoplastic syndromes, functioning and non functioning tumors, unifocal locally invasive, and advanced to multifocal tumors with disseminated distant metastases. The presence of various specific biomarkers and specific receptor targets serves as valuable tools for diagnosis, prognosis, and management. PET-CT with FDG and a multitude of novel and specific radiotracers towards specific therapeutic targets mandates personalization of their use, so as to ensure maximum clinical benefit in the management of these neoplasms.

Medullary Thyroid Cancer: An Experience from a Tertiary Care Hospital of a Developing Country

Background

Medullary thyroid carcinoma (MTC) is a rare type of thyroid cancer that occasionally occurs as part of MEN2A. The universal treatment of MTC is total thyroidectomy with central lymph node dissection. For disease progression, carcinoembryonic antigen (CEA) and calcitonin (CTN) need to be followed. Our aim was to study the presence and patterns of the above-mentioned characteristics of MTC in our population.

Methodology

This retrospective study was conducted in a tertiary care hospital of Pakistan in which data of thirty-two medullary thyroid cancer patients over the past 20 years were reviewed and analysed after fulfilment of inclusion criteria. Their clinical, pathological, biochemical and treatment modalities were recorded through a retrospective review of their medical record files.

Results

The mean age of patients was 42.88 ± 2.67 years in our study, with a male-to-female ratio of 2:1. Patients with sporadic MTC were 68.8%, while 31.2% were familial. The rates of metastasis were highest in bones followed by lungs and liver. Total thyroidectomy was performed in 26 (81.2%) patients and among those chemotherapy and XRT were performed in one and two patients, respectively. Histologically, the mean tumour size was 7.62 ± 3.64 cm. Median pre-surgery calcitonin was 5756 pg/ml that decreased to 29.3 pg/ml post-surgery. Median pre-surgery CEA level was 246.5 ng/ml that decreased to 6.39 ng/ml post-surgery. Two patients were RET positive.

Conclusion

MTC usually presents in the fourth decade of life with male predominance and mostly sporadic occurrence. Total thyroidectomy with subsequent serial calcitonin and CEA levels thereafter are the mainstay of treatment and follow-up.

What is the status of immunotherapy in thyroid neoplasms?

Immunotherapy has changed the treatment of patients with advanced cancer, with different phase III trials showing durable responses across different histologies. This review focuses on the preclinical and clinical evidence of potential predictive biomarkers of response and efficacy of immunotherapy in thyroid neoplasms. Programmed death-ligand 1 (PD-L1) staining by immunohistochemistry has shown higher expression in anaplastic thyroid cancer (ATC) compared to other subtypes. The tumor mutational burden in thyroid neoplasms is low but seems to be higher in ATC. Immune infiltrates in the tumor microenvironment (TME) differ between the different thyroid neoplasm subtypes. In general, differentiated thyroid cancer (DTC) has a higher number of tumor-associated lymphocytes and regulatory T cells (Tregs), while ATC and medullary thyroid cancer (MTC) display a high density of tumor-associated macrophages (TAMs). Nevertheless, results from clinical trials with immunotherapy as monotherapy or combinations have shown limited efficacy. Further investigation into new strategies aside from anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4)/programmed death 1 (PD-1)/PD-L1 antibodies, validation of predictive biomarkers, and better population selection for clinical trials in thyroid neoplasms is more than needed in the near future.

Development of Functional Thyroid C Cell-like Cells from Human Pluripotent Cells in 2D and in 3D Scaffolds

Medullary thyroid carcinoma contributes to about 3–4% of thyroid cancers and affects C cells rather than follicular cells. Thyroid C cell differentiation from human pluripotent stem cells has not been reported. We report the stepwise differentiation of human embryonic stem cells into thyroid C cell-like cells through definitive endoderm and anterior foregut endoderm and ultimobranchial body-like intermediates in monolayer and 3D Matrigel culture conditions. The protocol involved sequential treatment with interferon/transferrin/selenium/pyruvate, foetal bovine serum, and activin A, then IGF-1 (Insulin-like growth factor 1), on the basis of embryonic thyroid developmental sequence. As well as expressing C cell lineage relative to follicular-lineage markers by qPCR (quantitative polymerase chain reaction) and immunolabelling, these cells by ELISA (enzyme-linked immunoassay) exhibited functional properties in vitro of calcitonin storage and release of calcitonin on calcium challenge. This method will contribute to developmental studies of the human thyroid gland and facilitate in vitro modelling of medullary thyroid carcinoma and provide a valuable platform for drug screening.

Patient-Reported Outcomes with Selpercatinib Treatment Among Patients with RET-Mutant Medullary Thyroid Cancer in the Phase I/II LIBRETTO-001 Trial

BACKGROUND

Medullary thyroid cancer (MTC) standard of care includes multikinase inhibitors (MKIs), which can exacerbate disease-related diarrhea, primarily because of non-RET kinase inhibition. We report diarrhea and other patient-reported outcomes (PROs) with selpercatinib, a highly selective RET inhibitor, among patients with RET-mutant MTC in the ongoing, phase I/II LIBRETTO-001 trial.

MATERIALS AND METHODS

Instrument completion time points were baseline (cycle 1, day 1) and approximately every other 28-day cycle until cycle 13 (every 12 weeks thereafter) for the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30, and baseline, weekly during cycle 1, and day 1 of every cycle for the modified Systemic Therapy-Induced Diarrhea Assessment Tool (mSTIDAT). A ≥ 10-point change from baseline in domain score was considered clinically meaningful. PROs were summarized through cycle 13 in all patients and by subgroups with or without prior exposure to MKIs vandetanib and/or cabozantinib (V/C).

RESULTS

Among the overall MTC population (n = 226), 88 (39%) and 124 (55%) patients comprised the V/C-naïve and previous V/C subgroups, respectively. Compliance was >85% for both instruments at each time point. Most patients maintained/improved in all health-related quality of life (HRQoL) subscales throughout treatment. Improvements in diarrhea were clinically meaningful in 43.5% of patients overall and in 36.8% and 51.3% of V/C-naïve and previous V/C subgroups, respectively. At baseline, 80.4% of all patients reported diarrhea on mSTIDAT. The percentage of patients who reported diarrhea was reduced to less than half of all patients (range: 33.3%-48.3%) after cycle 2.

CONCLUSION

These interim results demonstrate that patients with RET-mutant MTC improved/remained stable on all domains of HRQoL during treatment with selpercatinib. Future analyses will be conducted as the data mature.

IMPLICATIONS FOR PRACTICE

Patients with metastatic medullary thyroid cancer (MTC) frequently experience disease-related diarrhea that can significantly impair daily living. Standards of care for the treatment of MTC include RET-targeted therapies as well as multikinase inhibitors (MKIs). Over 40% of patients with RET-mutant MTC who received selpercatinib, a highly selective RET inhibitor, reported clinical meaningful improvements in diarrhea in a phase I/II study. Patient-reported diarrhea improved in 36.8% of patients who had no previous treatment with MKIs and in 51.3% of patients who had previous treatment with MKIs. The percentage of patients who reported diarrhea prior to selpercatinib initiation (80.4%) was reduced to less than half (range: 33.3%-48.3%) after cycle 2 of selpercatinib treatment.

Anti-CEA Pretargeted Immuno-PET Shows Higher Sensitivity Than DOPA PET/CT in Detecting Relapsing Metastatic Medullary Thyroid Carcinoma: Post Hoc Analysis of the iPET-MTC Study

Pretargeting parameters for the use of anti-carcinoembryonic antigen (CEA) bispecific monoclonal antibody TF2 and the ⁶⁸Ga-labeled IMP288 peptide for immuno-PET have been optimized in a first-in-humans study performed on medullary thyroid carcinoma (MTC) patients (the iPET-MTC study). The aim of this post hoc analysis was to determine the sensitivity of immuno-PET in relapsing MTC patients, in comparison with conventional imaging and ¹⁸F-l-dihydroxyphenylalanine (¹⁸F-DOPA) PET/CT. Methods: Twenty-five studies were analyzed in 22 patients. All patients underwent immuno-PET 1 and 2 h after ⁶⁸Ga-IMP288 injection pretargeted by TF2, in addition to neck, thoracic, abdominal, and pelvic CT; bone and liver MRI; and ¹⁸F-DOPA PET/CT. The gold standard was histology or confirmation by one other imaging method or by imaging follow-up. Results: In total, 190 lesions were confirmed by the gold standard: 89 in lymph nodes, 14 in lungs, 46 in liver, 37 in bone, and 4 in other sites (subcutaneous tissue, heart, brain, and pancreas). The number of abnormal foci detected by immuno-PET was 210. Among these, 174 (83%) were confirmed as true-positive by the gold standard. Immuno-PET showed a higher overall sensitivity (92%) than ¹⁸F-DOPA PET/CT (65%). Regarding metastatic sites, immuno-PET had a higher sensitivity than CT, ¹⁸F-DOPA PET/CT, or MRI for lymph nodes (98% vs. 83% for CT and 70% for ¹⁸F-DOPA PET/CT), liver (98% vs. 87% for CT, 65% for ¹⁸F-DOPA PET/CT, and 89% for MRI), and bone (92% vs. 64% for ¹⁸F-DOPA PET/CT and 86% for MRI), whereas sensitivity was lower for lung metastases (29% vs. 100% for CT and 14% for ¹⁸F-DOPA PET/CT). Tumor SUV_max at 60 min ranged from 1.2 to 59.0, with intra- and interpatient variability. Conclusion: This post hoc study demonstrates that anti-carcinoembryonic antigen immuno-PET is an effective procedure for detecting metastatic MTC lesions. Immuno-PET showed a higher overall sensitivity than ¹⁸F-DOPA PET/CT for disclosing metastases, except for the lung, where CT remains the most effective examination.

How I treat medullary thyroid cancer

Medullary thyroid cancer (MTC) represents a rare neuroendocrine neoplasm originating from neoplastic C-cells in the thyroid gland. While localized disease is potentially curable with an optimized surgical approach, the number of relapses is high, and a considerable number of patients present with primary metastatic disease. Multidisciplinary management including standardized surveillance following surgery, but also early involvement of medical oncologists, is therefore important. Several oncogenic pathways are involved in the pathogenesis of MTC including vascular endothelial growth factor receptor, epidermal growth factor receptor, MET, and most importantly RET, and the multi-tyrosine kinase inhibitors vandetanib and cabozantinib have been approved for advanced MTC based on data from phase III studies. As activating RET mutations represent the most important driver, specific RET inhibitors were introduced and suggest high response rates with limited off-target toxicities. The current review provides a practical overview on clinical presentation and management from early to advanced MTC.

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Systemic treatment options in advanced MTC remain limited with particularly immunotherapy being ineffective.

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Multi-tyrosine kinase inhibitors remain the standard of care for advanced MTC.

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Recent approval of selective RET inhibitors is promising.

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Testing of RET mutations should be included routinely into the diagnostic algorithm.

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Multidisciplinary teams should be involved to guarantee the best outcome for our patients.

Diagnostic Challenges of Medullary Thyroid Carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) comprises 1-2% of all thyroid cancers, yet 15% of all thyroid cancer-related deaths. While up to 20% of cases may be predicted due to autosomal dominant germline mutations, 80% of cases are sporadic. However, due to non-specific presenting symptoms and diagnostic imaging, prompt diagnosis and treatment has remained elusive. This article will further investigate the limitations of MTC diagnosis and look into future areas for diagnostic improvement.

METHODS

Relevant articles were identified using a systematic PubMed and Google Scholar search.

RESULTS

Prophylactic total thyroidectomy for the 20% of MTC cases that are present in autosomal dominant disorder provides definitive treatment. Serum calcitonin (Ctn) screening has several technical limitations due to population variability and laboratory assay interference, but advances in laboratory technology and combined use with fine needle aspiration increase its sensitivity. Other serum assays such as carcinoembryonic antigen and procalcitonin have limited applicability. Thyroid ultrasound remains the gold standard for the initial diagnostic planning, with limited application for CT, MRI, and PET imaging.

CONCLUSION

With complete surgical resection the only definitive treatment, early MTC diagnosis has presented an elusive challenge, mainly due to its relative rarity and difficulty in finding an economic screening strategy. Careful family history combined with fine needle aspiration with serum Ctn analysis can improve diagnostic sensitivity and specificity to greater than 95%.

Ultrasonic Characteristics of Medullary Thyroid Carcinoma: Differential From Papillary Thyroid Carcinoma and Benign Thyroid Nodule

ABSTRACT

The aim of this study was to evaluate the differences in ultrasonic features of patients with medullary thyroid carcinoma (MTC), papillary thyroid carcinoma (PTC), and benign thyroid nodules. This study included 53 cases of MTC, 151 cases of PTC, and 200 cases of benign thyroid nodule which were pathologically confirmed. There were no significant differences in sex and thyroid gland involvement among the MTC, PTC, and benign thyroid nodule groups. The age among the 3 groups was statistically different (P = 0.002). The TNM stage of MTC was significantly higher than that of PTC (P < 0.001). Compared with PTC, the lesion size, shape, margin, echogenicity, internal nodule component, and blood flow were significantly different in MTC (P < 0.001, P < 0.001, P < 0.001, P < 0.001, P = 0.045, P < 0.001). However, there were no differences in the form of calcification and cervical lymph node involvement between the 2 groups (P = 0.671, P = 0.128). Except for the lesion size and shape (P = 0.068, P = 0.444), MTC group have significant differences in the grade of Thyroid Imaging Reporting and Data System, lesion margin, echogenicity, internal nodule component, calcification, cervical lymph node, and blood flow compared with benign thyroid nodule group (P < 0.001, P = 0.014, P = 0.032, P < 0.001, P < 0.001, P < 0.001). Our data indicate that ultrasound have important value in preoperative diagnosis of MTC. The ultrasonic features of MTC include relatively large nodules, aspect ratio less than 1, smooth edge, solid hypoechoic, microcalcification, and rich blood flow. It is necessary to combine multiple ultrasonic features for the differential diagnosis of MTC, PTC, and benign thyroid nodules.

Medullary thyroid cancer: molecular factors, management and treatment

Medullary thyroid cancer (MTC) is an infrequent neuroendocrine tumor, which amounts to 3–5% of all thyroid malignancies. Approximately 75–80% of MTCs are sporadic neoplasms. The rest of 20–25% are familial cases that belong to multiple endocrine neoplasia (MEN) syndromes, specifically MEN2 and MEN3. These cases of familial MTC are attributed to an activating germline mutation of a tyrosine kinase receptor gene, the rearranged during transfection (RET) proto-oncogene, located on chromosome 10q11.21. These mutations are also found in some cases of sporadic MTC. This review sets forth in summary the accepted guidelines and approaches regarding diagnosis, management, and treatment of MTC. Surgical resection is the standard care, and an early, prophylactic intervention is performed in genetic cases. Further investigation and understanding of the molecular pathways involved in the growth and advancement of MTC is required in order to provide efficient therapy in cases of progressive disease.

Diagnostic value of [18F]Fluorocholine PET/CT in detection of primary medullary thyroid cancer

OBJECTIVE

Medullary thyroid cancer (MTC) is a challenging neuroendocrine malignancy where the role of nuclear medicine imaging is currently limited. This paper investigates the potential diagnostic value of [¹⁸F]Fluorocholine PET/CT in primary MTC.

METHODS

We prospectively enrolled 25 patients (10 male, 15 female) with suspicion for primary MTC based on fine-needle aspiration biopsy (FNAB). All patients had a baseline three phase [¹⁸F]Fluorocholine PET/CT (2.5 MBq/kg): two regional head and neck and upper mediastinum studies at 5 min (first phase) and 120 min (third phase) and a whole-body PET/CT (from the skull vertex to mid-thighs) at 60 min (second phase). Any non-physiological radiotracer uptake was regarded as MTC positive. All patients referred to surgery had a preoperative neck-US. True lesion status was assessed using either histopathology, FNAB results or follow-up imaging and laboratory (calcitonin, CEA) results. Results with p < 0.05 were considered statistically significant.

RESULTS

Nineteen of 25 patients (76%) were surgically treated and histopathology reports were obtained. Patient-based sensitivity and positive predictive value for detection of any MTC lesion using [¹⁸F]Fluorocholine PET/CT were both 100%. Neck-US was more specific (100% vs 70%; p = 0.002) and had a higher positive predictive value than [¹⁸F]Fluorocholine PET/CT (100% vs 55%; p = 0.018) for N1a and N1b staging. [¹⁸F]Fluorocholine PET/CT had a higher sensitivity (100% vs 50%; p = 0.025) and higher negative predictive value (100% vs 81%; p = 0.026) than neck-US for N1b staging. The optimal SUV_max cut-off to differentiate malignant from benign neck lesions at 60 and 120 min was 2.56. Patients with M1 stage on PET/CT had higher calcitonin (median of 5,372 vs 496.6 pg/ml; p = 0.005) and CEA concentrations (median of 95.8 vs 18.65 µg/l; p = 0.034) compared to patients with M0 disease.

CONCLUSION

[¹⁸F]Fluorocholine PET/CT appears to be a promising radiotracer for primary staging of MTC by increasing diagnostic accuracy for N staging and detecting possible distant metastatic sites at initial presentation of disease.

Adoptive T cell immunotherapy for medullary thyroid carcinoma targeting GDNF family receptor alpha 4

Metastatic medullary thyroid cancer (MTC) is a rare but often aggressive thyroid malignancy with a 5-year survival rate of less than 40% and few effective therapeutic options. Adoptive T cell immunotherapy using chimeric antigen receptor (CAR)-modified T cells (CAR Ts) is showing encouraging results in the treatment of cancer, but development is challenged by the availability of suitable target antigens. We identified glial-derived neurotrophic factor (GDNF) family receptor alpha 4 (GFRα4) as a putative antigen target for CAR-based therapy of MTC. We show that GFRα4 is highly expressed in MTC, in parafollicular cells within the thyroid from which MTC originates, and in normal thymus. We isolated two single-chain variable fragments (scFvs) targeting GFRα4 isoforms a and b by antibody phage display. CARs bearing the CD3ζ and the CD137 costimulatory domains were constructed using these GFRα4-specific scFvs. GFRα4-specific CAR Ts trigger antigen-dependent cytotoxicity and cytokine production in vitro, and they are able to eliminate tumors derived from the MTC TT cell line in an immunodeficient mouse xenograft model of MTC. These data demonstrate the feasibility of targeting GFRα4 by CAR T and support this antigen as a promising target for adoptive T cell immunotherapy and other antibody-based therapies for MTC.

Unexpected Pathogenic RET p.V804M Variant Leads to the Clinical Diagnosis and Management of Medullary Thyroid Carcinoma

Patient: Female, 62-year-old

Final Diagnosis: Medullary thyroid microcarcinoma

Symptoms: No pain or swelling in her neck • no dysphagia or odynophagia • no changes in voice

Medication: —

Clinical Procedure: Genetic analysis

Specialty: Genetics

Biodegradable dendritic Boltorn™ nanoconstructs: A promising avenue for cancer theranostics

The family of Boltorn™ H40 dendrimers is an imperative subclass of hyperbranched biodegradable polymers (HBPs), which has received mounting attention as a result of its inimitable chemical, physical and biodegradable properties. These properties embrace three-dimensional dendrimeric nanoarchitecture to avert tanglement between polymer branches, adequate spatial cavities for increased encapsulation of guest molecules, good solubility as well as low viscosity to improve processability, and a huge number of surface functional groups for chemical manipulations. Similarly, low toxicity, non-immunogenicity, and natural biodegradation are significant and critical advantages in therapeutic applications as compared to other dendritic polymers. All these characteristics of Boltorn™ H40 are of pronounced importance for planning and developing advanced targeted cargo delivery carriers for cancer therapy. The present review highlights the applications of Boltorn™ H40 HBPs for the transport of chemotherapeutic agents to manage various types of cancers.

Comparison of 18F-NaF PET/CT with Other Imaging Methods in the Detection of Bone Metastases in Patients with Medullary Thyroid Cancer: a Report of a Series of 31 Cases

PURPOSE

To compare the 18F-NaF PET/CT studies (18F-NaF) with other imaging methods in the detection of skeletal metastases (SM) in patients with medullary thyroid cancer (MTC).

METHODS

We retrospectively analyzed 31 patients with MTC who performed 18F-NaF to assess SM. The results of the 18F-NaF were compared with other imaging methods performed for metastasis detection: 99Tc-MDP bone scan (BS), magnetic resonance imaging (MRI), contrast-enhanced CT (CT), and 68Ga-Dotatate and 18F-FDG PET/CT studies. A qualitative analysis comparing the 18F-NaF findings with the ones of the other methods was performed, and the results were classified as superior (>), equal (=), and inferior (<).

RESULTS

Eleven patients had no bone metastases detected on any of the imaging methods used. Twenty patients presented SM depicted on 18F-NaF. Of these 20 patients, 12 performed bone scan (in 9 18F-NaF > BS and in 3 18F-NaF = BS), 1 performed 18F-FDG (18F-NaF > 18F-FDG), 4 performed 68Ga-Dotatate (in 2 18F-NaF > 68Ga-Dotatate and in 2 18F-NaF = 68Ga-Dotatate), 20 performed CT of at least one body segment (in 15 18F-NaF = CT and in 5 18F-NaF > CT), and 16 performed MRI of at least one body segment, and in all of them, the 18F-NaF was equal to the MRI. Beside this, the 18F-NaF detected SM in body segments not routinely scanned in MRI and CT.

CONCLUSION

In patients with MTC, the 18F-NaF seems to be equal or superior to other imaging modalities in the detection of SM and allows the analysis of the whole skeletal in a single study.

Medullary Thyroid Cancer in Patients Older than 45-Epidemiologic Trends and Predictors of Survival

Simple Summary

Sporadic medullary thyroid cancer can occur anytime in life although they tend to present at a later age (≥45 years old) when the tumors are more easily discernible or become symptomatic. We present, in this study, a group of patients diagnosed with medullary thyroid cancer at or after 45 years of age when they are more likely to develop sporadic forms of medullary thyroid cancer with regard to their natural history and prognosis. In this study, we evaluated factors affecting survival in such patients. We found that the incidence of medullary thyroid cancer in patients ≥45 years of age is increasing. Our findings suggest that patients should be offered surgical resection at an early stage to improve their outcomes.

Abstract

Sporadic medullary thyroid cancer (MTC) can occur anytime in life although they tend to present at a later age (≥45 years old) when the tumors are more easily discernible or become symptomatic. We aimed to identify the factors affecting the survival in patients ≥45 years of age diagnosed with MTC. We analyzed the Surveillance, Epidemiology, and End Results (SEER) registry from 1973–2016 focusing on patients ≥45 years of age with MTC as an isolated primary. A total of 2533 patients aged ≥45 years with MTC were identified. There has been a statistically significant increase of 1.19% per year in the incidence of MTC for this group of patients. The disease was more common in females and the Caucasian population. Most patients had localized disease on presentation (47.6%). Increasing age and advanced stage of presentation were associated with worse survival with HR 1.05 (p < 0.001) and HR 3.68 (p < 0.001), respectively. Female sex and surgical resection were associated with improved survival with HR 0.74 (p < 0.001) and 0.36 (p < 0.001), respectively. In conclusion, the incidence of MTC in patients ≥45 years of age is increasing. Patients should be offered surgical resection at an early stage to improve their outcomes.

Notch Signaling in Thyroid Cancer

Thyroid cancer is the most common malignancy of the endocrine system with a steadily rising incidence. The term "thyroid cancer" encompasses a spectrum of subtypes, namely papillary thyroid cancer, follicular thyroid cancer, anaplastic thyroid cancer, and medullary thyroid cancer. Each subtype differs histopathologically and in degrees of cellular differentiation, which may be in part due to signaling of the Notch pathway. The Notch pathway is an evolutionarily conserved signal transduction mechanism that regulates cell proliferation, differentiation, survival, stem cell maintenance, embryonic and adult development, epithelial-mesenchymal transition, and angiogenesis. Its role in cancer biology is controversial, as it has been shown to play both an oncogenic and tumor-suppressive role in many different types of cancers. This discordance holds true for each subtype of thyroid cancer, indicating that Notch signaling is likely cell type and context dependent. Whether oncogenic or not, Notch signaling has proven to be significantly involved in the tumorigenesis of thyroid cancer and has thus earned interest as a therapeutic target. Advancement in the understanding of Notch signaling in thyroid cancer holds great promise for the development of novel treatment strategies to benefit patients.

Differential Diagnosis of Diarrhea in Patients With Neuroendocrine Tumors

Patients with neuroendocrine tumors (NETs) and carcinoid syndrome experience diarrhea that can have a debilitating effect on quality of life. Diarrhea also may develop in response to other hormonal syndromes associated with NETs, surgical complications, medical comorbidities, medications, or food sensitivities. Limited guidance on the practical approach to the differential diagnosis of diarrhea in these patients can lead to delays in appropriate treatment. This clinical review and commentary underscore the complexity in identifying the etiology of diarrhea in patients with NETs. Based on our collective experience and expertise, we offer a practical algorithm to guide medical oncologists and other care providers to expedite effective management of diarrhea and related symptoms in patients with NETs.

Small Cell Variant of Medullary Thyroid Carcinoma: A Possible Treatment

Small cell variant of medullary thyroid carcinoma is an extremely rare histologic entity with a paucity of data. As such, there is a lack of literature and clinical experience regarding this disease. In this report, we examine a case of small cell variant of medullary thyroid carcinoma that presented with intractable nausea, vomiting and diarrhea. While these symptoms were essentially refractory to the standard symptomatic treatment, further laboratory analysis revealed dramatically elevated calcitonin levels and mildly raised thyroid-stimulating hormone levels. Interestingly, repletion of thyroid hormone and treatment with lanreotide resulted in an abatement of our patient’s symptoms. This temporal clinical improvement highly suggests a potential role involving thyroid-stimulating hormone and calcitonin levels in the pathogenesis of this disease, and consequently suggests a role for thyroxine in treating the associated gastrointestinal symptoms. 

Genomic and Transcriptomic Characterization of Sporadic Medullary Thyroid Carcinoma

Background: Sporadic medullary thyroid carcinoma (MTC) is a relatively uncommon neuroendocrine malignancy and the molecular tumorigenesis of its sporadic type (sMTC) is only partially understood. In this study, we performed a study focusing on the genomic and transcriptomic characterization of sMTC. Methods: Twenty-nine sMTC patients were included. Whole-exome sequencing (WES) was carried out in 18 patients, including both tumor samples and matched noncancerous tissues. Whole transcriptome sequencing (RNA-Seq) was performed in all 29 tumors. WES, RNA-Seq, and copy number alteration (CNA) data were analyzed. A Cell Counting Kit-8 (CCK-8) assay was used to evaluate cell proliferation. Results: Among the somatic mutations, RET was the only recurrently cancer-related mutated gene (5/18, 27.8%). In the germline, FAT1 and FAT4, two members of the FAT gene family, were identified as the two most common mutated genes. CNA analysis found that FAT1 and FAT4, both located on chromosome 4q, were also two of the genes most commonly affected by somatic chromosomal deletions (4/18, 22.2%). Using TT and MZ-CRC-1 cell lines, the CCK-8 assay showed that FAT1 and FAT4 knockdown could promote MTC cell proliferation. Based on the gene expression profile, patients were clustered into two molecular subtypes: the mesenchymal-like subtype is characterized by epithelial-mesenchymal transition, while the proliferative-like subtype is associated with enrichment of cell cycle pathways. Most events of structural recurrence (80%) occurred in the proliferative-like subtype. Conclusion: In addition to RET, these findings demonstrate that FAT1/FAT4 genomic alterations appear to be frequent in sMTC. Two molecular subtypes of sMTC with distinct biological behavior could be identified. However, these results need to be validated by larger samples and more comprehensive experiments in the future, especially for the frequency and function of FAT1/FAT4 germline variants.

Clinical impact of 68Ga-DOTATATE PET-CT imaging in patients with medullary thyroid cancer

PURPOSE

Medullary thyroid cancer (MTC) arises from neuroendocrine C cells of the thyroid. There is no single diagnostic imaging method that can reveal all MTC recurrences or metastases. ⁶⁸Ga-DOTATATE is an alternative PET radiotracer that showed acceptable efficacy in the detection of MTC. In this study, we aimed to reveal the clinical efficacy and impact of this radiotracer on the management of patients with MTC.

METHODS

The ⁶⁸Ga-DOTATATE PET-CT records of 38 patients with confirmed MTC were included in the study. The demographic data, clinical indication for the scan, previous therapies, and tumor marker levels were recorded. The site and SUVmax of the lesions were also noted. A consensus was reached on the additional value of ⁶⁸Ga-DOTATATE PET-CT, and sites with discordant results on conventional imaging (CI). Finally, changes in management after the scan were evaluated.

RESULTS

⁶⁸Ga-DOTATATE PET-CT outperformed CI in 14/38 (37%) patients. In these 14 patients, metastatic lymph nodes were detected in 8, bone metastases in 4, and both bone and lymph nodes metastases in 2 patients. In 16/38 (42%) patients, ⁶⁸Ga-DOTATATE PET-CT performed equally well as CI. In 5/38 (13%) patients, CI outperformed PET-CT. Most of the patients (4/5) in this group had hepatic metastases. ⁶⁸Ga-DOTATATE PET-CT positivity was also correlated with tumor marker expression [median calcitonin; PET-positive: 743 ± 5439 vs PET-negative: 45 ± 17 (p:0.012), median CEA; PET-positive: 41 ± 162 vs PET-negative: 2.6 ± 1.4 (p:0.015)]. ⁶⁸Ga-DOTATATE PET-CT changed the clinical management of 13/38 (34%) patients. The information provided by PET-CT resulted in neck surgery in 5/13 patients, external radiotherapy in 3/13 and both in one patient. Four of these thirteen patients were found to be eligible for peptide receptor radionuclide therapy.

CONCLUSION

⁶⁸ Ga-DOTATATE is an essential part of the work-up for patients with MTC. This modality outperformed CI in 14/38 (37%) patients and changed the clinical management in 13/38 (34%) patients. Prospective randomized studies with image-guided therapy decisions are needed to further reveal the impact of PET imaging in patients with MTC.

Medullary Thyroid Carcinoma Presenting as Metastatic Disease to the Breast

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that is derived from C cells of the thyroid gland. It is a rare aggressive tumor, known to metastasize to lymph nodes, liver, bones, and lungs. A 41-year-old female, who presented with a breast mass, was initially diagnosed with invasive ductal carcinoma. She was also found to have a thyroid mass which was later diagnosed as MTC. On a rereview of the breast pathology, the morphologic features were strikingly similar to the MTC. Further investigation revealed that this was in fact a very rare case of MTC that had metastasized to the breast. We have identified 20 cases of MTC metastasizing to the breast in the literature that supports its occurrence as a real possibility. Albeit rare, medullary thyroid carcinoma should be considered in the differential diagnosis of a breast mass.

Thyroid cancer histological subtypes based on tumor size: National perspective

BACKGROUND

Thyroid tumor size is an important prognostic factor. The aim of this study is to examine the histological subtypes and management of thyroid cancer based on tumor size (≤4 cm vs >4 cm).

METHODS

Retrospective cohort study utilizing the National Cancer Database, 2004-2014.

RESULTS

A total of 152 387 patients were included, 13 614 (8.9%) of whom had a tumor size >4 cm. Histological subtypes of tumors >4 cm were: 69.6% papillary thyroid carcinoma, 17.5% FTC, 7.9% HCC, and 2.8% medullary thyroid carcinoma (MTC). High-volume hospitals for thyroid surgery were less likely to perform two-stage thyroidectomy, particularly for tumors ≤4 cm. Low-volume hospitals had a higher risk of staged thyroidectomy for MTC ≤4 cm (19.8%) compared with high-volume hospitals (8.7%) (P < .001).

CONCLUSIONS

This study describes the prevalence of thyroid cancer subtypes. In the era of a conservative approach to differentiated thyroid carcinoma, there could be a potential increase in the risk of staged thyroidectomy.

Tumor detection of the thyroid and salivary glands using hyperspectral imaging and deep learning

The performance of hyperspectral imaging (HSI) for tumor detection is investigated in ex-vivo specimens from the thyroid (N = 200) and salivary glands (N = 16) from 82 patients. Tissues were imaged with HSI in broadband reflectance and autofluorescence modes. For comparison, the tissues were imaged with two fluorescent dyes. Additionally, HSI was used to synthesize three-band RGB multiplex images to represent the human-eye response and Gaussian RGBs, which are referred to as HSI-synthesized RGB images. Using histological ground truths, deep learning algorithms were developed for tumor detection. For the classification of thyroid tumors, HSI-synthesized RGB images achieved the best performance with an AUC score of 0.90. In salivary glands, HSI had the best performance with 0.92 AUC score. This study demonstrates that HSI could aid surgeons and pathologists in detecting tumors of the thyroid and salivary glands.

Carcinoembryonic antigen should be concurrently checked with calcitonin to identify distant metastases in medullary thyroid cancer

Aim: This study investigates if serum calcitonin or carcinoembryonic antigen (CEA) levels can differentiate between locoregional and metastatic medullary thyroid cancer. Methods: A single institution retrospective analysis was performed on 88 patients with medullary thyroid cancer between 2008 and 2014. Results: In M0disease, calcitonin (p < 0.001) and CEA (p = 0.003) significantly decreased postoperatively. Not only was the correlation significant between calcitonin and CEA preoperatively (r = 0.72; p < 0.001) and postoperatively (r = 0.68; p < 0.001), calcitonin could extrapolate CEA levels (p < 0.001). These findings were statistically insignificant in metastatic disease. Conclusion: Independently, calcitonin and CEA fail to differentiate between locoregional and metastatic disease. Both are essential for prognostication: loss of concordance is suspicious for metastatic disease. Hence, discordant CEA and calcitonin levels should be an indication to pursue additional imaging.

Salinomycin and its derivatives as potent RET transcriptional inhibitors for the treatment of medullary thyroid carcinoma

Rearranged during transfection kinase (RET) is a validated molecular target in medullary thyroid cancer (MTC), as activating mutations in RET are often associated with the development of MTC. The present study reports the first preclinical characterization of salinomycin and selected analogs as potent RET transcriptional inhibitors. Reverse transcription‑PCR and immunoblotting revealed that salinomycin profoundly decreased RET expression in the TT human MTC cell line by inhibiting RET transcription. Moreover, salinomycin resulted in remarkable anti‑proliferative activity against MTC that is driven by RET (gain of function mutation) by selectively inhibiting the intracellular PI3K/Akt/mTOR signaling pathway. Also, flow cytometry and fluorescence‑activated cell sorting showed that salinomycin induces G1 phase arrest and apoptosis by reducing the expression of retinoblastoma protein, E2F1, cyclin D and CDK4. The structure‑activity relationship of salinomycin was investigated in this study. Some of the salinomycin derivatives showed the ability to reduce RET expression where others fail to alter RET expression. These results suggest that the RET‑suppressing effect of salinomycin may be largely attributed to disruption of the Wnt pathway, presumably through interference with the ternary LRP6‑Frizzled‑Wnt complex. Furthermore, these findings support the further preclinical evaluation of salinomycin and its analogs as a promising new class of therapeutic agents for the improved treatment of MTC.

Long-Term Oncologic Outcomes After Curative Resection of Familial Medullary Thyroid Carcinoma

INTRODUCTION

Long-term outcomes after curative resection in patients with germline RET mutations and medullary thyroid cancer (MTC) are highly variable and mutation-specific oncologic outcomes are not well-described.

METHODS

Sixty-six patients identified from 1986 to 2017 from a single-institution cancer database were assessed for recurrence and survival using Kaplan-Meier estimates, and correlated with clinicopathologic features using log-rank or Cox proportional hazards.

RESULTS

Median follow-up was 9.3 years (range 0.3-31.5), median tumor diameter was 1.5 cm (range 0.1-7.5), and preoperative calcitonin was known in 41 patients [median 636 (range 0-9600)]. Overall survival (OS) of the cohort was 94% at 10 years, the cumulative incidence of locoregional recurrence was 38% at 10 years, and 19/24 (79%) patients underwent repeat neck operation. The cumulative incidence of distant recurrence was 27% at 10 years. Predictors of distant recurrence were tumor size, positive lymph nodes, and pre- and postoperative carcinoembryonic antigen, but not calcitonin. M918T mutation-bearing patients had 10-year distant recurrence-free survival of 0%, compared with 83% in all other patients (p < 0.001), and equivalent 10-year OS (100% vs. 92%; p = 0.49).

CONCLUSIONS

Structural and metastatic recurrence is common in patients with germline RET mutations, and MTC and can occur 20 years after initial treatment, however survival remains high. Management should focus on optimal surveillance strategies and long-term control of structural disease.

Medullary Thyroid Carcinoma: An Update on Imaging

Medullary thyroid carcinoma (MTC), arising from the parafollicular C cells of the thyroid, accounts for 1–2% of thyroid cancers. MTC is frequently aggressive and metastasizes to cervical and mediastinal lymph nodes, lungs, liver, and bones. Although a number of new imaging modalities for directing the management of oncologic patients evolved over the last two decades, the clinical application of these novel techniques is limited in MTC. In this article, we review the biology and molecular aspects of MTC as an important background for the use of current imaging modalities and approaches for this tumor. We discuss the modern and currently available imaging techniques—advanced magnetic resonance imaging (MRI)-based techniques such as whole-body MRI, dynamic contrast-enhanced (DCE) technique, diffusion-weighted imaging (DWI), positron emission tomography/computed tomography (PET/CT) with 18F-FDOPA and 18F-FDG, and integrated positron emission tomography/magnetic resonance (PET/MR) hybrid imaging—for primary as well as metastatic MTC tumor, including its metastatic spread to lymph nodes and the most common sites of distant metastases: lungs, liver, and bones.

RET Kinase-Regulated MicroRNA-153-3p Improves Therapeutic Efficacy in Medullary Thyroid Carcinoma

Background: Medullary thyroid carcinoma (MTC) presents a disproportionate number of thyroid cancer deaths due to limited treatment options beyond surgery. Gain-of-function mutations of the human REarranged during Transfection (RET) proto-oncogene have been well-established as the key driver of MTC tumorigenesis. RET has been targeted by tyrosine kinase inhibitors (TKIs), such as cabozantinib and vandetanib. However, clinical results have been disappointing, with regular dose reductions and inevitable progression. This study aimed to identify RET-regulated microRNAs (miRNAs) and explore their potential as novel therapeutic targets. Methods: Small RNA sequencing was performed in MTC TT cells before and after RET inhibition to identify RET-regulated miRNAs of significance. In vitro gain-of-function studies were performed to investigate cellular and molecular effects of potential miRNAs on cell phenotypes. Systemic delivery of miRNA in MTC xenografts using EDV™ nanocells, targeted to epidermal growth factor receptor on tumor cells, was employed to assess the therapeutic potential and possible modulation of TKI responses. Results: The study demonstrates the tumor suppressive role of a specific RET-regulated miRNA, microRNA-153-3p (miR-153-3p), in MTC. Targeted intravenous delivery of miR-153-3p impeded the tumor growth in MTC xenografts. Furthermore, combined treatment with miR-153-3p plus cabozantinib caused greater growth inhibition and appeared to reverse cabozantinib resistance. Mechanistically, miR-153-3p targets ribosomal protein S6 kinase B1 (RPS6KB1) of mTOR signaling and reduced downstream phosphorylation of Bcl-2 associated death promoter. Conclusion: This study provides evidence to establish systemic miRNA replacement plus TKIs as a novel therapeutic for patients with metastatic, progressive MTC.

Expression of Prox1 in Medullary Thyroid Carcinoma Is Associated with Chromogranin A and Calcitonin Expression and with Ki67 Proliferative Index, but Not with Prognosis

Medullary thyroid carcinoma (MTC) has been shown to express Prospero homeobox protein 1 (Prox1), a transcription factor whose expression is altered in a variety of human cancers. We conducted a retrospective study on a series of 32 patients with MTC to test the correlation of Prox1 expression in MTC with clinicopathological features and to evaluate its prognostic significance. Correlation of Prox1 immunohistochemical expression with tumor size, proliferative index (Ki67), and calcitonin and CEA serum levels prior to surgery was tested for significant correlations. The difference in Prox1 and Ki67 immunohistochemical expression according to the immunohistochemical staining intensity of CEA, chromogranin A, and calcitonin was tested using the Kruskal-Wallis H test and linear regression analysis. The prognostic value of Prox1 and Ki67 for our patient cohort was assessed by Kaplan-Meier log rank survival analysis. We demonstrated a positive correlation between Prox1 expression and Ki67 index. Prox1 also showed significant difference in expression according to chromogranin A and calcitonin immunohistochemical expression, with higher Prox1 expression in tumors with stronger chromogranin A or calcitonin staining. Prox1 expression did not correlate with PFS or OS based on Kaplan-Meier log rank survival analysis. In conclusion, Prox1 expression in MTC is positively correlated with Ki67 and with the immunohistochemical expression of chromogranin A and calcitonin. However, the present study does not support a role for Prox1 in MTC prognosis.

Epigenetic regulation of RET receptor tyrosine kinase and non-coding RNAs in MTC

Medullary thyroid carcinoma (MTC) is an aggressive and rare cancer with limited treatment options for metastatic disease. Due to this, there is a need for a better understanding of MTC biology in the hope of improved treatments. One area of improved understanding of cancer biology is epigenetics. Epigenetics is defined as cellular processes which alter gene expression independent of changes in the primary DNA sequence. These processes include modifications such as DNA methylation, microRNA deregulation and post-translational histone modifications, all of which have been implicated in tumorigenesis of MTC. Transcription of the main driver of MTC - the REarranged during Transfection (RET) proto-oncogene can also be modulated by epigenetic alterations. This review will present a review of MTC and its epigenetic links with a particular focus on targeting epigenetic mechanisms as novel therapeutic strategies.

Educational Case: Endocrine Neoplasm: Medullary Thyroid Carcinoma

Medullary thyroid cancer is a rare neuroendocrine tumor that arises the neural crest-derived parafollicular C cells and accounts for approximately 5% to 10% of thyroid cancers worldwide. These tumor can occur sporadically or as part of hereditary tumor syndromes, such as multiple endocrine neoplasia 2 and familial medullary thyroid cancer. The most common clinical presentation is a solitary thyroid nodule. The genetic defect in these disorders involves the RET proto-oncogene which is important for diagnosis of medullary thyroid cancer (including screening for hereditary medullary thyroid cancer) and for treatment guidance. This review summarizes the molecular basis and clinicopathologic features of medullary thyroid carcinoma.

Management of treatment-related toxicities in advanced medullary thyroid cancer

Progress in the treatment of advanced medullary thyroid cancer (MTC) has resulted from the approval of 2 drugs within the past 5 years, vandetanib and cabozantinib. These multikinase inhibitors (MKIs) possess overlapping specificities for multiple kinase targets implicated in the progression of MTC. Both drugs are associated with toxicities, including hypertension, hemorrhage/perforation, diarrhea and other gastrointestinal events, several dermatologic events, and hypothyroidism. In addition, vandetanib is uniquely associated with QTc prolongation through interaction with myocardial potassium channels, and cabozantinib is uniquely associated with hand-foot skin reaction. Treatment-related toxicities occur frequently and can be severe or life-threatening, and patients undergoing long-term treatment will likely experience adverse events (AEs). Here we offer specific practical recommendations for managing AEs commonly occurring with vandetanib and cabozantinib. The recommended approach relies on early recognition and palliation of symptoms, dose interruption, and dose reduction as necessary in order for the patient to maintain the highest tolerable dose for as long as possible and optimal quality of life. Treatment guidelines do not specify a recommended sequence for treating with vandetanib and cabozantinib; however, most patients will receive both drugs during their lifetime. The choice for first-line therapy is individualized after a risk-benefit assessment and depends on physician preference and patient-related factors, such as comorbid conditions. Because most generalist practices may not be familiar with the intricacies of agents such as vandetanib and cabozantinib, we commend that patients with advanced MTC be managed and treated by a thyroid cancer specialist with coordination of care within a multidisciplinary team.

Medullary Thyroid Cancer: Overview and Case Study of a Rare Cancer

BACKGROUND

Medullary thyroid cancer (MTC) is a rare cancer that has historically been managed by endocrinologists. In 2011, the first of several multi- targeted tyrosine kinase inhibitors was approved as treatment for MTC. These drugs have changed the management of MTC to teams that include oncologists and oncology nurses.

OBJECTIVES

This article illustrates MTC diagnostics, surveillance, management of adverse drug reactions, and disease progression through a case study.

METHODS

An overview of MTC is offered, followed by an in-depth case study that examines MTC from the patient's perspective.

FINDINGS

Oncology nurses can influence patient outcomes through the provision of patient education, support, and management of disease and treatment complications.

National Trends in the Surgical Treatment of Non-advanced Medullary Thyroid Cancer (MTC): An Evaluation of Adherence with the 2009 American Thyroid Association Guidelines

BACKGROUND

Medullary thyroid cancer (MTC) represents the third most common type of thyroid cancer, and the prognosis depends on the stage of the disease at diagnosis and completeness of tumor resection. In 2009, the American Thyroid Association (ATA) published guidelines with evidence-based recommendations for the treatment of MTC. This study aimed to determine national adherence rates of the treatment according to the ATA guidelines specific for MTC.

METHODS

Patients diagnosed with MTC from 2004 to 2013 were identified from the National Cancer Database. Guideline adherence rates for the treatment of MTC before and after the publication of ATA guidelines were analyzed and compared to determine patient and clinical variables that affected treatment.

RESULTS

A total of 3693 patients diagnosed with MTC were identified. We found 60.3 % of the patients had localized MTC and 39.7 % had regional metastases. Older age, female sex and having Medicaid or being uninsured were directly correlated with more advanced disease upon diagnosis (p < 0.001). Overall, a greater proportion of patients received care in accordance with the recommendations following the ATA guidelines' publication in 2009: 61.4 % of patients treated between 2004 and 2008 versus 66.8 % of patients treated between 2009 and 2013 received care in accordance with the recommendations (p < 0.01). Factors such as older age, African American race, localized disease at diagnosis, lower estimated median zip code household income and being treated in a community versus an academic hospital were associated with a lower likelihood of receiving care in accordance with the guidelines.

CONCLUSION

Adherence rates to the ATA recommendations for the treatment of MTC increased modestly following the publication of guidelines in 2009 with the largest increase seen in community hospitals. Being older, African American, diagnosed with localized disease and treated in a community hospital rather than in an academic institution was correlated with a lower likelihood of receiving treatment in accordance with the guidelines. Efforts should be made to continuously increase the adherence rates to the MTC ATA guidelines and to decrease socioeconomic disparities that continue to exist in the treatment of MTC.

Antineoplastic effects of histone deacetylase inhibitors in neuroendocrine cancer cells are mediated through transcriptional regulation of Notch1 by activator protein 1

Notch signaling is minimally active in neuroendocrine (NE) cancer cells. While histone deacetylase inhibitors (HDACi) suppress NE cancer growth by inducing Notch, the molecular mechanism underlying this interplay has not yet been defined. NE cancer cell lines BON, H727, and MZ-CRC-1 were treated with known HDACi Thailadepsin-A (TDP-A) and valproic acid (VPA), and Notch1 mRNA expression was measured with RT-PCR. Truncated genomic fragments of the Notch1 promotor region fused with luciferase reporter were used to identify the potential transcription factor (TF) binding site. The key regulatory TF was identified with the electrophoretic mobility shift assay (EMSA). The effect of HDACi on Notch1 level was determined before and after silencing the TF. TDP-A and VPA induced Notch1 mRNA in a dose-dependent manner. A functional DNA motif at -80 to -52 from the Notch1 start codon responsible for the HDACi-dependent Notch1 induction was identified. Mutation of this core sequence failed to induce luciferase activity despite HDACi treatment. EMSA showed the greatest gel shift with AP-1 in nuclear extracts. Knockdown of AP-1 significantly attenuated the effect of HDACi on Notch1 induction. Interestingly, AP-1 transfection did not alter Notch1 level, suggesting that AP-1 is necessary but insufficient for HDACi activation of Notch1. Therefore, AP-1 is the TF that binds to a specific transcription-binding site within the Notch1 promotor region to trigger Notch1 transcription. Elucidating the HDACi activation mechanism may lead to the development of novel therapeutic options against NE cancers and facilitate the identification of clinical responders and prevent adverse effects.

Histone deacetylase inhibitor thailandepsin-A activates Notch signaling and suppresses neuroendocrine cancer cell growth in vivo

Novel therapies for neuroendocrine (NE) cancers are desperately needed as they frequently present as metastatic disease and cause debilitating symptoms by secreting excessive hormones. Induction of Notch isoforms has a tumor suppressive effect in NE cancer cell lines, and we have observed that histone deacetylase inhibitors (HDACi) potently activate Notch. In this study, we describe the potential for Burkholderia thailandensis-derived class I HDACi thailandepsin A (TDP-A) as a Notch activator and therapeutic agent against NE cancer. IC₅₀ for TDP-A was determined to be 4-6 nM in NE cancer cell lines (BON, MZ-CRC-1, and TT) without cytotoxicity to lung fibroblasts. The binding characteristics of TDP-A to its target HDAC1 was examined using bioluminescence resonance energy transfer (BRET). Western blot and flow cytometry analysis showed that TDP-A induces cell cycle arrest and apoptosis in a dose-dependent manner. TDP-A dose-dependently activated the Notch pathway as measured by increasing functional CBF1-luciferase reporter signal and mRNA and protein expressions of Notch isoforms, which were attenuated by pretreatment with γ-secretase inhibitor DAPT. Furthermore, TDP-A lead to changes in expression level of downstream targets of Notch pathway and reduced expression of NE cancer markers. An in vivo study demonstrated that TDP-A suppressed NE cancer progression. These results show that TDP-A, as a Notch activator, is a promising agent against NE cancers.

Medullary Thyroid Carcinoma in MEN2A: ATA Moderate- or High-Risk RET Mutations Do Not Predict Disease Aggressiveness

CONTEXT

High-risk RET mutations (codon 634) are associated with earlier development of medullary thyroid carcinoma (MTC) and presumed increased aggressiveness compared with moderate-risk RET mutations.

OBJECTIVE

To determine whether high-risk RET mutations are more aggressive.

DESIGN

Retrospective cohort study using institutional multiple endocrine neoplasia type 2 registry.

SETTING

Tertiary cancer care center.

PATIENTS

Patients with MTC and moderate- or high-risk germline RET mutation.

INTERVENTION

None (observational study).

MAIN OUTCOME MEASURES

Proxies for aggressiveness were overall survival (OS) and time to distant metastatic disease (DMD).

RESULTS

A total of 127 moderate-risk and 135 high-risk patients were included (n = 262). Median age at diagnosis was 42.3 years (range, 6.4 to 86.4 years; mean, 41.6 years) for moderate-risk mutations and 23.0 years (range, 3.7 to 66.8 years; mean, 25.6 years) for high-risk mutations (P < 0.0001). Moderate-risk patients had more T3/T4 tumors at diagnosis (P = 0.03), but there was no significant difference for N or M stage and no significant difference in OS (P = 0.40). From multivariable analysis for OS, increasing age [hazard ratio (HR), 1.05/y; 95% confidence interval (CI), 1.03 to 1.08], T3/T4 tumor (HR, 2.73; 95% CI, 1.22 to 6.11), and M1 status at diagnosis (HR, 3.93; 95% CI, 1.61 to 9.59) were significantly associated with worse OS but high-risk mutation was not (P = 0.40). No significant difference was observed for development of DMD (P = 0.33). From multivariable analysis for DMD, only N1 status at diagnosis was significant (HR, 2.10; 95% CI, 1.03 to 4.27).

CONCLUSIONS

Patients with high- and moderate-risk RET mutations had similar OS and development of DMD after MTC diagnosis and therefore similarly aggressive clinical courses. High-risk connotes increased disease aggressiveness; thus, future guidelines should consider RET mutation classification by disease onset (early vs late) rather than by risk (high vs moderate).