Neoadjuvant selpercatinib for advanced medullary thyroid cancer

[Update on medullary thyroid carcinoma-What is relevant for surgeons?]

This article provides an overview of surgically relevant diagnostic and operative aspects of medullary thyroid carcinoma (MTC) regarding current trends from recent studies and the expected adaptation of national S3 guidelines. The article addresses individual patient treatment options based on recognizable risk factors, the intraoperative resection strategy and standard procedures as well as the characteristics of sporadic and hereditary MTC with the concept of prophylactic thyroidectomy.

Landmark Studies in Differentiated Thyroid Cancer

Surgical resection remains the mainstay of curative intent therapy for patients with differentiated thyroid cancer, with radioactive iodine ablation and/or TSH suppression commonly employed in the adjuvant setting. Alternative strategies such as active surveillance and ablation are potentially available for patients with very low risk disease, although data regarding long term oncologic outcomes are limited. While only a small subset of patients with DTC will require systemic therapy, an increased understanding of tumor mutation profiles and available targeted therapies may facilitate multidisciplinary treatment of patients with locally advanced and/or unresectable DTC. This landmark series will summarize key studies that shape current guidelines in the surgical management of DTC and its adjuncts, with particular attention to current controversies and novel therapeutics that impact surgical management.

The potential role of neoadjuvant treatment in thyroid cancers in the era of kinase inhibitors: a narrative review

AIM

To analyse the literature on the potential role of kinase inhibitors (KI) as neoadjuvant treatment (NAT) in all thyroid cancers (TC).

MATERIALS AND METHODS

Online databases were systematically examined, including MEDLINE (via PubMed) Embase, ISI Web of Science, Google Scholar, and Scopus. As many papers were published before the classification of TC was revised, our search was conducted as follows: NAT in TC, NAT in papillary thyroid cancer (PTC), NAT in follicular thyroid cancer (FTC), NAT in anaplastic thyroid cancer (ATC), and NAT in medullary thyroid cancer (MTC).

RESULTS

The search revealed 21 single case reports and three small series on NAT in TC. Overall, 32 cases were found: 24 follicular cell derived cancers (FCDC) of which nine were ATC, eight were MTC. We also found four major retrospective series, in two of which the cohort was divided and analysed into different groups according to the kind of treatment. In these four series, NAT was performed in in a total of 99 patients (32 FCDC, 60 ATC, and 7 MTC).

CONCLUSIONS

While awaiting large-scale clinical trials, the literature highlights that NAT may be an option for locally advanced TC (and above all ATC) when surgery may be too destructive or when the tumour is inoperable. The use of NAT should be discussed with the patient. An R0 or at least an R1 should be the goal of NAT, and the molecular profile should be performed as rapidly as possible.

Neoadjuvant systemic therapy for inoperable differentiated thyroid cancers: Impact on tumor resectability

BACKGROUND

Limited treatment options exist for inoperable thyroid cancers. We evaluated whether neoadjuvant use of systemic tyrosine kinase inhibitors facilitates surgery of differentiated thyroid cancers in this challenging context.

METHODS

A single-institution experience of 42 patients receiving tyrosine kinase inhibitors for papillary, follicular and anaplastic thyroid carcinomas between 2018 and 2023 was reviewed to identify differentiated thyroid cancers treated with neoadjuvant tyrosine kinase inhibitors (dabrafenib/trametinib, lenvatinib/pembrolizumab, or lenvatinib alone) via multidisciplinary protocols.

RESULTS

Nine patients with differentiated thyroid cancers (age 49 years, range 19-80, 5 women, 4 men) received neoadjuvant tyrosine kinase inhibitors with intent to improve resectability of primary or recurrent/residual tumors. All had locoregionally advanced disease deemed either unresectable or resectable with unacceptable morbidities. Six exhibited distant metastases (6 lungs, 6 vertebral/axial bones, 1 sternum). Tumors had BRAF V600E (6 papillary thyroid carcinoma) or RAS/TERT (2 follicular thyroid carcinoma) mutations or NCOA4-RET fusion. Most received neoadjuvant tyrosine kinase inhibitors for <6 months with visible results within weeks, radiologically and by examination. All patients completing surgery achieved R0 resection without major surgical complications or aerodigestive structure resection. Neoadjuvant tyrosine kinase inhibitors were generally well-tolerated (4 minor, 1 major toxicity that halted therapy but not surgery). Unique patients with distant metastases continued to receive adjuvant tyrosine kinase inhibitors. At median postoperative follow-up of 2 years, all patients are alive without new locoregional recurrence.

CONCLUSION

Neoadjuvant use of tyrosine kinase inhibitors seems extremely effective in downstaging surgically unresectable differentiated thyroid cancers to achieve R0 resection while avoiding unnecessary surgical morbidities. A multidisciplinary approach with early genomic profiling to guide personalized neoadjuvant use of tyrosine kinase inhibitors is essential. Prospective studies are urgently needed to define the potential role of neoadjuvant tyrosine kinase inhibitors in advanced thyroid cancer management.

State of Knowledge About Thyroid Cancers in the Era of COVID-19-A Narrative Review

Thyroid cancer (TC), due to its heterogeneous nature, remains a clinical challenge. Many factors can initiate the carcinogenesis process of various types of TC, which complicates diagnosis and treatment. The presented review gathers current information on specific types of TC, taking into account the effects of the COVID-19 pandemic. It is likely that COVID-19 has influenced and continues to influence the function of the thyroid gland. A high percentage of patients with COVID-19 showing simultaneous pathological changes in the thyroid suggests that SARS-CoV-2 may disrupt the function of this gland and initiate pro-oxidative mechanisms, inflammatory states, and autoimmune diseases, thereby promoting the formation of neoplastic changes. Furthermore, changes in the expression of the ACE2, TMPRSS2, CLEC4M and DPP4 genes, observed in TC, also occur in COVID-19. Therefore, it is probable that the interaction of SARS-CoV-2 with thyroid cell receptors may initiate carcinogenesis in this gland. Additionally, some drugs used in TC therapy (e.g., levothyroxine) may increase the affinity of SARS-CoV-2 for cells, which could contribute to a more severe course of COVID-19 and the emergence of long-term symptoms (post-COVID-19). Moreover, the consequences of sanitary restrictions (limited access to medical services, reduction in endocrinological and oncological procedures) that took place in many countries during the COVID-19 pandemic may lead in the future to an increased number of missed diagnoses and the emergence of aggressive cancers.

Adverse event profiles of selpercatinib: a real-world pharmacovigilance analysis based on FAERS database

BACKGROUND

Selpercatinib, a highly selective tyrosine kinase inhibitor, has emerged as an excellent treatment option for patients with rearranged during transfection-altered cancer. However, there is limited comprehensive safety information available for selpercatinib through large-scale post-marketing monitoring.

METHODS

This study conducted a comprehensive analysis of selpercatinib-related adverse events (AEs) using the FDA Adverse Event Reporting System database. Four disproportionality methods were employed to identify potential AEs associated with selpercatinib. Specifically, this study investigated the differences in AEs of selpercatinib with respect to reporter continent, indication, sex, age, weight, dose, frequency, and onset time.

RESULTS

A total of 464 reports and 1,007 selpercatinib-related AEs were identified. Three new significant AEs were discovered, including dysphagia, pericardial effusion, and hemiparesis. Notably, Asia reported hepatic function abnormal more frequently, especially in patient administered doses exceeding 160 mg. Furthermore, hypersensitivity was reported more frequently by Asia and in individuals weighing less than 50 kg.

CONCLUSIONS

It is paramount to stay vigilant concerning the potential emergence of three newly identified AEs. Significant differences were found in selpercatinib-related AEs concerning reporter continent, sex, weight, dose, frequency, and onset time, which deserved clinical attention. These findings contribute to a broader understanding of the AE profiles of selpercatinib.

Management of pediatric thyroid carcinoma

PURPOSE OF REVIEW

The incidence of thyroid carcinoma is increasing among children and adolescents, particularly in female individuals. Children and adolescents require special considerations in management as the molecular genetics of pediatric thyroid tumors are inherently different from their adult counterparts. The increased risk of malignancy, nodal metastases, and pulmonary metastases in pediatric patients warrants pediatric-specific management recommendations and pediatric-specific multidisciplinary teams.

RECENT FINDINGS

This article highlights the molecular origins of pediatric thyroid carcinoma and the implications of tumor genetics for the course of disease and treatment considerations. We highlight specific surgical considerations to optimize outcomes while minimizing lifelong risks of vocal paralysis and hypoparathyroidism. The landscape of treatment options is rapidly evolving with development of sophisticated molecular approaches to understand the genetic landscape, and this review features updated recommendations and systemic treatment options for the management of pediatric thyroid malignancy.

SUMMARY

Pediatric thyroid carcinoma is a lifelong burden and the treatment tailored to optimize outcomes minimizes long-term risks of treatments, surgery, radiation and targeted systemic therapies. Multidisciplinary teams that treat pediatric thyroid carcinoma should focus surgical experience and use the most updated guidelines and treatments available, particularly considering the landscape of molecular genetics in pediatric thyroid carcinoma.

Multidisciplinary Canadian consensus on the multimodal management of high-risk and radioactive iodine-refractory thyroid carcinoma

Most follicular cell-derived differentiated thyroid carcinomas are regarded as low-risk neoplasms prompting conservative therapeutic management. Here, we provide consensus recommendations reached by a multidisciplinary group of endocrinologists, medical oncologists, pathologists, radiation oncology specialists, a surgeon and a medication reimbursement specialist, addressing more challenging forms of this malignancy, focused on radioactive iodine (RAI)-resistant or -refractory differentiated thyroid carcinoma (RAIRTC). In this document we highlight clinical, radiographic, and molecular features providing the basis for these management plans. We distinguish differentiated thyroid cancers associated with more aggressive behavior from thyroid cancers manifesting as poorly differentiated and/or anaplastic carcinomas. Treatment algorithms based on risk-benefit assessments of different multimodal therapy approaches are also discussed. Given the scarcity of data supporting management of this rare yet aggressive disease entity, these consensus recommendations provide much needed guidance for multidisciplinary teams to optimally manage RAIRTC.

Molecular genetics, therapeutics and RET inhibitor resistance for medullary thyroid carcinoma and future perspectives

Medullary thyroid carcinoma (MTC) is a rare type of thyroid malignancy that accounts for approximately 1-2% of all thyroid cancers (TCs). MTC include hereditary and sporadic cases, the former derived from a germline mutation of rearrangement during transfection (RET) proto-oncogene, whereas somatic RET mutations are frequently present in the latter. Surgery is the standard treatment for early stage MTC, and the 10-year survival rate of early MTC is over 80%. While for metastatic MTC, chemotherapy showing low response rate, and there was a lack of effective systemic therapies in the past. Due to the high risk (ca. 15-20%) of distant metastasis and limited systemic therapies, the 10-year survival rate of patients with advanced MTC was only 10-40% from the time of first metastasis. Over the past decade, targeted therapy for RET has developed rapidly, bringing hopes to patients with advanced and progressive MTC. Two multi-kinase inhibitors (MKIs) including Cabozantinib and Vandetanib have been shown to increase progression-free survival (PFS) for patients with metastatic MTC and have been approved as choices of first-line treatment. However, these MKIs have not prolonged overall survival (OS) and their utility is limited due to high rates of off-target toxicities. Recently, new generation TKIs, including Selpercatinib and Pralsetinib, have demonstrated highly selective efficacy against RET and more favorable side effect profiles, and gained approval as second-line treatment options. Despite the ongoing development of RET inhibitors, the management of advanced and progressive MTC remains challenging, drug resistance remains the main reason for treatment failure, and the mechanisms are still unclear. Besides, new promising therapeutic approaches, such as novel drug combinations and next generation RET inhibitors are under development. Herein, we overview the pathogenesis, molecular genetics and current management approaches of MTC, and focus on the recent advances of RET inhibitors, summarize the current situation and unmet needs of these RET inhibitors in MTC, and provide an overview of novel strategies for optimizing therapeutic effects.

Neoadjuvant Treatment in Locally Advanced Thyroid Carcinoma

Although the focus in the last decades has been on the overdiagnosis of incidentally detected thyroid carcinomas in early stages, the other extreme of the disease is represented by locally advanced tumors with the invasion of neighboring structures. These are infrequent tumors, but they have a high complexity and a poor prognosis. In the absence of effective therapies allowing preoperative tumor reduction, in order to achieve a more restricted surgery, treatment was limited to aggressive surgery with resection of the aerodigestive tract and major vascular structures or palliative treatment. However, due to the increased knowledge of tumor biology and the results that tyrosine kinase inhibitors have achieved in the treatment of radioactive iodine-refractory tumors, neoadjuvant therapy with a curative intent has emerged as a reality to be taken into account when dealing with these patients. This paper presents a narrative review of the current scientific evidence regarding neoadjuvant treatment in locally advanced thyroid cancer.

Pediatric Medullary Thyroid Carcinoma: Clinical Presentations and Long-Term Outcomes in 144 Patients Over 6 Decades

CONTEXT

Sporadic medullary thyroid carcinoma (sMTC) rarely occurs in childhood and no studies have specifically focused on this entity.

OBJECTIVE

To describe the clinical presentations and long-term outcomes of a large cohort of children and young adults with sMTC compared with hereditary MTC (hMTC).

METHODS

Retrospective study of 144 patients diagnosed with MTC between 1961 and 2019 at an age ≤ 21 years and evaluated at a tertiary referral center.

RESULTS

In contrast to hMTC (n = 124/144, 86%), patients with sMTC (n = 20/144, 14%) are older (P < .0001), have larger tumors (P < .0001), a higher initial stage grouping (P = .001) and have more structural disease (P = .0045) and distant metastases (DM) (P = .00084) at last follow-up, but are not more likely to die from MTC (P = .42). Among 77 patients diagnosed clinically, not by family history (20/20 sMTC and 57/124 hMTC), there was no difference in the initial stage (P = .27), presence of DM at diagnosis (P = 1.0), disease status at last follow-up (P = .13), overall survival (P = .57), or disease-specific survival (P = .87). Of the 12 sMTC tumors that underwent somatic testing, 11 (91%) had an identifiable alteration: 10 RET gene alterations and 1 ALK fusion.

CONCLUSION

sMTC is primarily a RET-driven disease that represents 14% of childhood-onset MTC in this cohort. Pediatric sMTC patients are older, present with clinical disease at a more advanced TNM classification, and have more persistent disease at last follow-up compared with hMTC, but these differences disappear when comparing those presenting clinically. Somatic molecular testing should be considered in sMTC patients who would benefit from systemic therapy.

Effect and Safety of Apatinib as Neoadjuvant Therapy in Locally Advanced Differentiated Thyroid Cancer: A Phase 2 Trial

Context

Presently, there is a paucity of prospective clinical trials investigating neoadjuvant therapy for locally advanced thyroid cancer.

Objective

This study was a multicenter, open-label, single-arm, phase II trial evaluating the efficacy and safety of apatinib as neoadjuvant therapy in patients with local advanced differentiated thyroid cancer (DTC).

Methods

Patients were treated with preoperative apatinib over a course of 2 to 4 cycles, culminating in surgical resection. The primary endpoints were objective response rate (ORR) and disease control rate (DCR); the secondary endpoints were the rate of R0 surgery, alterations in serum thyroglobulin levels, disease-free survival, and adverse events (AEs).

Results

A total of 14 patients who met the inclusion criteria were administered neoadjuvant apatinib. Among these, 13 patients underwent surgical procedures following apatinib treatment and were enrolled in the ITT population. The ORR was 53.8% and the DCR was 100%. Of the patients, 84.6% received R0 surgery, while the remaining 15.4% underwent R1 resection. Predominant among the observed AEs were hypertension, hand-foot syndrome, hepatic dysfunction, proteinuria, and hypothyroidism, with no instances of grade 4 or 5 AEs reported. Subsequent to surgery, patients were followed up for a median period of 34 months, during which disease progression occurred in 5 individuals (35.7%), encompassing 3 cases of locoregional recurrences and 2 cases of distant metastases.

Conclusion

Apatinib may be an effective agent in the use of neoadjuvant therapy for locally advanced DTC. Patients may therefore benefit from surgical outcomes and their long-term prognosis.

Medullary Thyroid Cancer: Molecular Drivers and Immune Cellular Milieu of the Tumour Microenvironment-Implications for Systemic Treatment

In this review, we explore the underlying molecular biology of medullary thyroid carcinoma (MTC) and its interplay with the host immune system. MTC is consistently driven by a small number of specific pathogenic variants, beyond which few additional genetic events are required for tumorigenesis. This explains the exceedingly low tumour mutational burden seen in most MTC, in contrast to other cancers. However, because of the low tumour mutational burden (TMB), there is a correspondingly low level of tumour-associated neoantigens that are presented to the host immune system. This reduces tumour visibility and vigour of the anti-tumour immune response and suggests the efficacy of immunotherapy in MTC is likely to be poor, acknowledging this inference is largely based on the extrapolation of data from other tumour types. The dominance of specific RET (REarranged during Transfection) pathogenic variants in MTC tumorigenesis rationalizes the observed efficacy of the targeted RET-specific tyrosine kinase inhibitors (TKIs) in comparison to multi-kinase inhibitors (MKIs). Therapeutic durability of pathway inhibitors is an ongoing research focus. It may be limited by the selection pressure TKI treatment creates, promoting survival of resistant tumour cell clones that can escape pathway inhibition through binding-site mutations, activation of alternate pathways, and modulation of the cellular and cytokine milieu of the tumour microenvironment (TME).

Spontaneous and Treatment-Related Changes of Serum Calcitonin in Medullary Thyroid Cancer: Long-Term Experience in a Patient With Multiple Endocrine Neoplasia Type 2B

PURPOSE

Medullary thyroid carcinoma (MTC) in MEN2B syndrome is associated with germline RET mutation. Patients harboring de novo mutations are usually diagnosed at more advanced disease stages. We present a young woman with Met918Th mutation diagnosed with stage IV MTC at age 10 years.

METHODS

The disease progressed despite total thyroidectomy and multiple surgical interventions for cervical lymph node recurrences, leading to distant metastases in the fifth year after the initial diagnosis. Subsequently, she underwent five different types of tyrosine kinase inhibitor (TKI) treatments. The 17-year disease course was divided into periods defined by four surgical interventions and sequential treatment intervals with four multikinase (sunitinib, vandetanib, cabozantinib, and lenvatinib) and one RET-selective TKI (selpercatinib). Tumor growth for different phases of spontaneous development and drug treatment intervals was characterized by changes in serial log-transformed calcitonin measurements (n = 114).

RESULTS

Three operations (one for calcitonin-producing adrenal pheochromocytoma) were associated with drops in calcitonin levels. All of the nonselective TKIs were stopped due to adverse effects. As reflected by the negative calcitonin doubling rate, the best treatment response was observed with selpercatinib, which was associated with an initial large drop followed by a decreasing calcitonin trajectory over 514 days without any major side effects.

CONCLUSION

This case of MEN2B medullary thyroid cancer with long-term survival presents how the effectiveness of different treatment modalities can be estimated using log-transformed calcitonin levels. Furthermore, our experience supports the view that serial calcitonin measurements may be more sensitive than radiological follow-up in advanced MTC. Our patient also represents a new case of rarely reported calcitonin-producing pheochromocytomas.

Tissue-Agnostic Cancer Therapy Approvals

Tumor-agnostic, or histology-agnostic, cancer therapy marks a groundbreaking evolution in the realm of precision oncology. In stark contrast to conventional cancer treatments that categorize malignancies based on their tissue of origin (eg, breast, lung, renal cell, etc), tumor-agnostic therapies transcend histologic boundaries, honing in on the genetic and molecular attributes of tumors, regardless of their location. This article offers a comprehensive review of the current landscape of tissue-agnostic cancer therapies and provides clinical insights to empower surgical oncologists with a deeper understanding of these innovative therapeutic approaches.

Decreasing utilization for postoperative radiation therapy in locoregionally advanced medullary thyroid cancer

BACKGROUND

Use of postoperative radiation therapy (PORT) in locoregionally advanced medullary thyroid cancer (MTC) remains controversial. The objective was to evaluate the effect of PORT on locoregional control (LRC) and overall survival (OS).

METHODS

Retrospective cohort study of 346 MTC patients separated into PORT and no-PORT cohorts. Relative indications for PORT, as well as changes in patterns of treatment, were recorded.

RESULTS

49/346 (14%) received PORT. PORT was associated with worse OS; adjusted HR = 2.0 (95%CI 1.3-3.3). PORT was not associated with improved LRC, even when adjusting for advanced stage (Stage III p = 0.892; Stage IV p = 0.101). PORT and targeted therapy were not associated with improved OS compared to targeted therapy alone; adjusted HR = 1.2 (95%CI 0.3-4.1).

CONCLUSIONS

Use of PORT in MTC has decreased and its indications have become more selective, coinciding with the advent of effective targeted therapies. Overall, PORT was not associated with improved LRC or OS.

The Efficacy and Safety of Surufatinib Combined with Anti PD-1 Antibody Toripalimab in Neoadjuvant Treatment of Locally Advanced Differentiated Thyroid Cancer: A Phase II Study

BACKGROUND

Surgery is the primary treatment for locally advanced differentiated thyroid cancer (DTC). However, some locally advanced patients are not candidates for R0/1 resection. There is limited evidence of neoadjuvant treatment in locally advanced DTC. Surufatinib targets multiple kinases, which is efficient, tolerable, and safe in patients with radioiodine-refractory DTC. In addition, surufatinib plus toripalimab (an anti-PD-1 antibody) showed encouraging antitumor activity in advanced solid tumors. This study was designed to evaluate the efficacy and safety of surufatinib plus toripalimab in locally advanced DTC in the neoadjuvant setting.

METHODS

In this single-arm, phase II study, patients with pathologically confirmed unresectable or borderline resectable DTC were eligible and received a combination of 250 mg of surufatinib (orally daily) with 240 mg of toripalimab (intravenous, every 3 weeks). Treatment continued until satisfied for curative surgery, disease progression, withdrawal of consent, unacceptable toxicity, or investigator decision. Primary endpoint was objective response rate (ORR). Secondary endpoints included R0/1 resection rate, adverse events (AEs), etc. RESULTS: Ten patients were enrolled and received at least 4 cycles of treatment. The ORR was 60%. Nine patients received R0/1 resections after neoadjuvant treatment. The median best percentage change in the sum of the target lesion diameter was 32%. Most adverse events (AEs) were grade 1 or 2.

CONCLUSIONS

Surufatinib in combination with toripalimab as neoadjuvant therapy for locally advanced DTC was feasible, and the majority of patients achieved R0/1 resection. It represents a new option for locally advanced DTC and needs further investigation.

Natural History and Predictive Factors of Outcome in Medullary Thyroid Microcarcinoma

CONTEXT

Management of sporadic medullary thyroid microcarcinoma smaller than 1 cm (micro-MTC) is controversial because of conflicting reports of prognosis. As these cancers are often diagnosed incidentally, they pose a management challenge when deciding on further treatment and follow-up.

OBJECTIVE

We report the outcomes of surgically managed sporadic micro-MTC in a specialist endocrine surgery and endocrinology unit and identify associations for recurrence and disease-specific survival in this population.

METHODS

Micro-MTCs were identified from a prospectively maintained surgery database, and slides were reviewed to determine pathological grade. The primary end points were recurrence, time to recurrence and disease-specific survival. Prognostic factors assessed included size, grade, lymph node metastasis (LNM), and postoperative calcitonin.

RESULTS

From 1995 to 2022, 64 patients were diagnosed with micro-MTC with 22 excluded because of hereditary disease. The included patients had a median age of 60 years, tumor size of 4 mm, and 28 (67%) were female. The diagnosis was incidental in 36 (86%) with 4 (10%) being high grade, 5 (12%) having LNM and 9 (21%) having elevated postoperative calcitonin. Over a 6.6-year median follow-up, 5 (12%) developed recurrence and 3 (7%) died of MTC. High grade and LNM were associated with 10-year survival estimates of 75% vs 100% for low grade and no LNM (hazard ratio = 831; P < .01). High grade, LNM, and increased calcitonin were associated with recurrence (P < .01). Tumor size and type of surgery were not statistically significantly associated with recurrence or survival. No patients with low grade micro-MTC and normal postoperative calcitonin developed recurrence.

CONCLUSION

Most sporadic micro-MTCs are detected incidentally and are generally associated with good outcomes. Size is not significantly associated with outcomes. Using grade, LNM, and postoperative calcitonin allows for the identification of patients at risk of recurrence to personalize management.

Efficacy and Safety of RET-Specific Kinase Inhibitors in RET-Altered Cancers: A Systematic Review

RET proto-oncogene encodes receptor tyrosine kinase. Selpercatinib and pralsetinib are the only RET-specific tyrosine kinase inhibitors approved by FDA in RET-altered tumors. We searched PubMed, Embase, Cochrane, WOS, and Clinicaltrials.gov. Objective-response, complete-response, and partial-response were 60-89%, 0-11%, and 55-89%, respectively, with the use of RET-specific drugs. ≥Grade 3 adverse events were seen in 28-53% of the patients, with hypertension, change in ALT, QT prolongation, neutropenia, and pneumonitis among the common side effects. Hence, selpercatinib and pralsetinib were effective and well tolerated by most of the patients with RET-altered tumors.

Medullary thyroid carcinoma

INTRODUCTION

Medullary thyroid carcinoma (MTC) constitutes approximately 5-10% of all thyroid cancers. Although the tumor forms in the thyroid, it doesn't originate from thyroid cells, but from the C cells or parafollicular cells which produce and release a hormone called calcitonin (CT). Starting from the second half of the 1900s, MTC was progressively studied and defined.

AREAS COVERED

This study aims to analyze the history, clinical presentation and biological behavior of MTC, bio-humoral and instrumental diagnosis, molecular profiling, genetic screening, preoperative staging and instrumental procedures, indispensable in expert and dedicated hands, such as high-resolution ultrasonography, CT-scan, MRI and PET/TC. We examine recommended and controversial surgical indications and procedures, prophylactic early surgery and multiple endocrine neoplasia surgery. Also, we discuss pathological anatomy classification and targeted therapies. The role of serum CT is valued both as undisputed and constant preoperative diagnostic marker, obscuring cytology and as early postoperative marker that predicts disease persistence.

EXPERT OPINION

With a complete preoperative study, unnecessary or useless, late and extended interventions can be reduced in favor of tailored surgery that also considers quality of life. Finally, great progress has been made in targeted therapy, with favorable impact on survival.

Current perspectives on the management of patients with advanced RET-driven thyroid cancer in Europe

The incidence of thyroid cancer is increasing worldwide with the disease burden in Europe second only to that in Asia. In the last several decades, molecular pathways central to the pathogenesis of thyroid cancer have revealed a spectrum of targetable kinases/kinase receptors and oncogenic drivers characteristic of each histologic subtype, such as differentiated thyroid cancer, including papillary, follicular, and medullary thyroid cancer. Oncogenic alterations identified include B-Raf proto-oncogene (BRAF) fusions and mutations, neurotrophic tyrosine receptor kinase (NTRK) gene fusions, and rearranged during transfection (RET) receptor tyrosine kinase fusion and mutations. Multikinase inhibitors (MKIs) targeting RET in addition to multiple other kinases, such as sorafenib, lenvatinib and cabozantinib, have shown favourable activity in advanced radioiodine-refractory differentiated thyroid cancer or RET-altered medullary thyroid cancer; however, the clinical utility of MKI RET inhibition is limited by off-target toxicity resulting in high rates of dose reduction and drug discontinuation. Newer and selective RET inhibitors, selpercatinib and pralsetinib, have demonstrated potent efficacy and favourable toxicity profiles in clinical trials in the treatment of RET-driven advanced thyroid cancer and are now a therapeutic option in some clinical settings. Importantly, the optimal benefits of available specific targeted treatments for advanced RET-driven thyroid cancer require genetic testing. Prior to the initiation of systemic therapy, and in treatment-naïve patients, RET inhibitors may be offered as first-line therapy if a RET alteration is found, supported by a multidisciplinary team approach.

Management of Advanced Thyroid Cancer: Overview, Advances, and Opportunities

Thyroid cancer is the most common endocrine malignancy with almost one million people living with thyroid cancer in the United States. Although early-stage well-differentiated thyroid cancers account for the majority of thyroid cancers on diagnosis and have excellent survival rates, the incidence of advanced-stage disease has increased over the past few years and confers poorer prognosis. Until recently, patients with advanced thyroid cancer had limited therapeutic options. However, the landscape of thyroid cancer treatment has dramatically changed in the past decade with the current availability of several novel effective therapeutic options, leading to significant advances and improved patient outcomes in the management of advanced disease. In this review, we summarize the current status of advanced thyroid cancer treatment options and discuss recent advances made in targeted therapies that have proven promising to clinically benefit patients with advanced thyroid cancer.

A Contemporary Review of the Treatment of Medullary Thyroid Carcinoma in the Era of New Drug Therapies

Medullary thyroid cancer (MTC) is a rare neuroendocrine tumor that can be sporadic or inherited and is often associated with mutations in the RET (Rearranged during Transfection) oncogene. The primary treatment for MTC is surgical resection of all suspected disease, but recent advances in targeted therapies for MTC, including the selective RET inhibitors selpercatinib and pralsetinib, have led to changes in the management of patients with locally advanced, metastatic, or recurrent MTC. In this article, we review updates on the evaluation and management of patients with MTC, focusing on new and emerging therapies that are likely to improve patient outcomes.

Clinical outcomes of combined cervical and transthoracic surgical approaches in patients with advanced thyroid cancer

BACKGROUND

Advanced thyroid disease involving the mediastinum may be managed surgically with a combined transcervical and transthoracic approach. Contemporary analysis of this infrequently encountered cohort will aid the multidisciplinary team in personalizing treatment approaches.

METHODS

Retrospective review of patients undergoing combined transcervical and transthoracic surgery for thyroid cancer at a single high-volume institution from 1994 to 2015.

RESULTS

Thirty-eight patients with median age 59 years (range 28-76) underwent surgery without perioperative mortality. Most patients had primary disease. A majority had distant metastases outside the mediastinum but had locoregionally curable disease. Common complications were temporary (39%) and permanent (18%) hypoparathyroidism, and wound infection (13%). One-year overall survival was 84%; 1-year locoregional disease-free survival was 64%. Median time to locoregional recurrence was 36 months. Only esophageal invasion was associated with worse oncologic outcomes.

CONCLUSIONS

Combined transcervical and transthoracic surgery for advanced thyroid cancer can be performed without mortality and with acceptable morbidity.

Development and validation of an RNA sequencing-based classifier for medullary thyroid carcinoma on thyroid FNA

This commentary describes the development and validation of the Afirma RNA sequencing–based classifier for medullary thyroid carcinoma (MTC). The importance of the early diagnosis of MTC is discussed along with the limitations of cytomorphology alone.

Pediatric thyroid cancer: Recent developments

Thyroid cancer is rare in children but its incidence is increasing. Recent data have clarified important similarities and differences between thyroid cancers originating in childhood and in adulthood. The genetic drivers of pediatric thyroid cancers are similar to those in adult tumors but comprise more gene fusions and fewer point mutations. Clinically, despite frequent metastatic spread, pediatric thyroid cancer has an excellent prognosis and mortality is rare. Therefore, treatment approaches must weigh carefully the morbidity of thyroid cancer treatments against their benefits. Current key questions include which children require total thyroidectomy rather than more limited-and safer-lobectomy, and in which children does the benefit of radioactive iodine therapy outweigh its risk of inducing a secondary malignancy. Finally, molecular therapies targeting genetic drivers of thyroid cancer now provide effective treatment for children with progressive, radioiodine-refractory disease, as well as opportunities to explore novel neoadjuvant uses that facilitate therapeutic surgery or radioactive iodine.

Medullary thyroid cancer - An update

Medullary thyroid cancer (MTC) is a rare neuroendocrine disease, encompassing about 5% of all thyroid cancers. Due to its peculiar features, this rare tumour offers unique possibilities for translational research studies. It arises from neuroendocrine parafollicular cells in an endocrine organ, and appears as a nodule apparently indistinguishable from thyroid nodules. It has a very peculiar progression with micro metastases difficult to identify, often-remaining stable during years and suddenly undergoing a rapid and unrestrainable progression. Moreover, MTC is one of the neoplasms with the best genetic characterization either in its sporadic or familial form, providing a valuable background to test targeted drugs. In the era of precision medicine, this review aims to give an update on the diagnostic tools, the therapeutic options for advanced MTC, and the most promising opportunities for a personalized follow up.

Preclinical Evaluation of Novel Tyrosine-Kinase Inhibitors in Medullary Thyroid Cancer

Simple Summary

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor arising from parafollicular calcitonin-secreting C cells of the thyroid. Most of the patients affected by MTC, especially the familial form, harbor a mutation of the RET proto-oncogene. In patients with advanced disease, medical therapy is represented by two tyrosine-kinase inhibitors: cabozantinib and vandetanib. However, their usage is limited by several adverse events and drug-resistance onset. The aim of this preclinical study was to evaluate the antitumor activity of novel molecules for the therapy of MTC: SU5402, an inhibitor of the fibroblast growth factor receptor type 1 (FGFR-1) and vascular endothelial growth factor receptor (VEGFR)-2; sulfatinib, a multi-target kinase inhibitor selective for FGFR-1 and the VEGFR-1, -2, and -3; SPP86, a RET-specific inhibitor. Our results suggest a potential role in targeting the FGFR and VEGFR signaling pathways as an alternative strategy for resistant tumors and a significative antitumor activity of this new RET-specific inhibitor.

Abstract

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor arising from parafollicular C cells of the thyroid gland. In this preclinical study, we tested three tyrosine-kinase inhibitors (TKIs): SU5402, a selective inhibitor of fibroblast growth factor receptor (FGFR)-1 and vascular endothelial growth factor receptor (VEGFR)-2; sulfatinib, an inhibitor of FGFR-1 and VEGFR-1, -2, -3; and SPP86, a RET-specific inhibitor. The effects of these compounds were evaluated in vitro in two human MTC cell lines (TT and MZ-CRC-1), and in vivo using xenografts of MTC cells in zebrafish embryos. SU5402, sulfatinib and SPP86 decreased cell viability. Sulfatinib and SPP86 significantly induced apoptosis in both cell lines. Sulfatinib and SPP86 inhibited the migration of TT and MZCRC-1 cells, while SU5402 was able to inhibit migration only in TT cells. In vivo we observed a significant reduction in TT cell-induced angiogenesis in zebrafish embryos after incubation with sulfatinib and SPP86. In conclusion, sulfatinib and SPP86 displayed a relevant antitumor activity both in vitro and in vivo. Moreover, this work suggests the potential utility of targeting FGFR and VEGFR signaling pathways as an alternative therapy for MTC.

Durable Disease Control by RET Inhibitor Selpercatinib in a Heavily Pre-Treated RET Fusion-Positive Papillary Thyroid Cancer

Standard treatment for unresectable papillary thyroid carcinoma (PTC) is a multi-kinase inhibitor, including lenvatinib and sorafenib. Rearranged during transfection (RET) fusions are found in approximately 10% of PTC. Here, we present a case of metastatic RET fusion-positive PTC with long-term disease control by selective RET inhibition. A 72-year-old woman with PTC and multiple lymph nodes and lung metastases progressed after initial lenvatinib and subsequent sorafenib treatment. Reintroduction of lenvatinib led to marked tumour shrinkage. During the rechallenge with lenvatinib, molecular screening of the tumour specimen revealed a CCDC6-RET gene fusion. The patient was enrolled in a phase 1/2 trial of the potent and specific RET inhibitor selpercatinib. All target and non-target lesions responded to selpercatinib in parallel with a remarkable decrease in serum thyroglobulin levels. Although a new lesion appeared in the right adrenal gland 14 months after the initiation of selpercatinib, ongoing stable disease was observed in all lesions over 28 months, including the new adrenal lesion. Adverse events included grade 3 fatigue, grade 2 anorexia, and grade 4 thrombocytopaenia but were easily manageable by suspension and dose reduction of selpercatinib. Selective kinase inhibition with selpercatinib provides RET fusion-positive PTC with clinical benefits, even in patients heavily pre-treated with multi-kinase inhibitors. This case supports the importance of routine molecular profiling in patients with PTC to identify uncommon but actionable gene alterations, such as RET gene fusions.

Precision oncology for RET-related tumors

Aberrant activation of the RET proto-oncogene is implicated in a plethora of cancers. RET gain-of-function point mutations are driver events in multiple endocrine neoplasia 2 (MEN2) syndrome and in sporadic medullary thyroid cancer, while RET rearrangements are driver events in several non-medullary thyroid cancers. Drugs able to inhibit RET have been used to treat RET-mutated cancers. Multikinase inhibitors were initially used, though they showed modest efficacy and significant toxicity. However, new RET selective inhibitors, such as selpercatinib and pralsetinib, have recently been tested and have shown good efficacy and tolerability, even if no direct comparison is yet available between multikinase and selective inhibitors. The advent of high-throughput technology has identified cancers with rare RET alterations beyond point mutations and fusions, including RET deletions, raising questions about whether these alterations have a functional effect and can be targeted by RET inhibitors. In this mini review, we focus on tumors with RET deletions, including deletions/insertions (indels), and their response to RET inhibitors.

Somatic RET Indels in Sporadic Medullary Thyroid Cancer: Prevalence and Response to Selpercatinib

CONTEXT

Although the majority of RET alterations are single nucleotide variants (SNV), small deletions and/or insertions have been reported at variable prevalence. No information about the efficacy of RET-specific inhibitors in patients harboring RET indels has been provided.

OBJECTIVE

We present an update on the prevalence of RET indels in medullary thyroid cancer (MTC) and describe the efficacy of selpercatinib in patients with advanced MTC with RET indels.

METHODS

The MTC tissues of 287 patients were analyzed using an Ion S5 targeted sequencing. The functional role of the reported indels have been evaluated by MutationTaster. Clinical and pathological data of MTC patients harboring a RET indel were collected and analyzed. Two patients with a RET indel were treated with selpercatinib.

RESULTS

Among 178 RET-positive cases, 147 (82.6%) harbored a SNV and 31 (17.4%) a RET in-frame indel. Nine indels were not previously reported and were found to be disease causing by MutationTaster. Patients harboring an indel were found to have an aggressive disease and 2 of them were treated with selpercatinib, experiencing a good response to the treatment.

CONCLUSION

These data show that RET indels are not infrequent and correlate with an aggressive disease. Two RET indel-positive patients showed a partial response to the treatment with a highly selective RET inhibitor; thus, these RET indels can be considered actionable mutations. In order to not miss these alterations, the analysis of the full gene is recommended.

American Head and Neck Society Endocrine Surgery Section and International Thyroid Oncology Group consensus statement on mutational testing in thyroid cancer: Defining advanced thyroid cancer and its targeted treatment

BACKGROUND

The development of systemic treatment options leveraging the molecular landscape of advanced thyroid cancer is a burgeoning field. This is a multidisciplinary evidence-based statement on the definition of advanced thyroid cancer and its targeted systemic treatment.

METHODS

An expert panel was assembled, a literature review was conducted, and best practice statements were developed. The modified Delphi method was applied to assess the degree of consensus for the statements developed by the author panel.

RESULTS

A review of the current understanding of thyroid oncogenesis at a molecular level is presented and characteristics of advanced thyroid cancer are defined. Twenty statements in topics including the multidisciplinary management, molecular evaluation, and targeted systemic treatment of advanced thyroid cancer are provided.

CONCLUSIONS

With the growth in targeted treatment options for thyroid cancer, a consensus definition of advanced disease and statements regarding the utility of molecular testing and available targeted systemic therapy is warranted.

Novel Therapeutics and Treatment Strategies for Medullary Thyroid Cancer

Medullary thyroid cancer is a rare thyroid malignancy with unique management considerations. In general, small intrathyroidal tumors are cured by total thyroidectomy with central compartment dissection, while large tumors and those with disease spread to regional lymph nodes and distant organs (most commonly lung, liver, and bone) are more difficult to cure. The last decade has seen significant progress in the treatment of advanced MTC, largely due to the discovery and availability of novel targeted therapies, including new drugs specifically targeting the RET protooncogone.

Thyroid Cancer and COVID-19: Prospects for Therapeutic Approaches and Drug Development

Thyroid cancer is the most prevalent endocrine malignancy and the reported incidence of thyroid cancer has continued to increase in recent years. Since 2019, coronavirus disease 2019 (COVID-19) has been spreading worldwide in a global pandemic. COVID-19 aggravates primary illnesses and affects disease management; relevant changes include delayed diagnosis and treatment. The thyroid is an endocrine organ that is susceptible to autoimmune attack; thus, thyroid cancer after COVID-19 has gradually attracted attention. Whether COVID-19 affects the diagnosis and treatment of thyroid cancer has also attracted the attention of many researchers. This review examines the literature regarding the influence of COVID-19 on the pathogenesis, diagnosis, and treatment of thyroid cancer; it also focuses on drug therapies to promote research into strategies for improving therapy and management in thyroid cancer patients with COVID-19.

Sporadic Medullary Thyroid Carcinoma: Towards a Precision Medicine

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignant tumor originating from parafollicular C-cells producing calcitonin. Most of cases (75%) are sporadic while the remaining (25%) are hereditary. In these latter cases medullary thyroid carcinoma can be associated (multiple endocrine neoplasia type IIA and IIB) or not (familial medullary thyroid carcinoma), with other endocrine diseases such as pheochromocytoma and/or hyperparathyroidism. RET gene point mutation is the main molecular alteration involved in MTC tumorigenesis, both in sporadic and in hereditary cases. Total thyroidectomy with prophylactic/therapeutic central compartment lymph nodes dissection is the initial treatment of choice. Further treatments are needed according to tumor burden and rate of progression. Surgical treatments and local therapies are advocated in the case of single or few local or distant metastasis and slow rate of progression. Conversely, systemic treatments should be initiated in cases with large metastatic and rapidly progressive disease. In this review, we discuss the details of systemic treatments in advanced and metastatic sporadic MTC, focusing on multikinase inhibitors, both those already used in clinical practice and under investigation, and on emerging treatments such as highly selective RET inhibitors and radionuclide therapy.

Real-world insights into the efficacy and safety of tyrosine kinase inhibitors against thyroid cancers

Based on clinical trials demonstrating favorable short-term efficacy and tolerable toxicity, several tyrosine kinase inhibitors have been approved for treating locally recurrent or metastatic, progressive radioiodine-refractory differentiated thyroid cancer, BRAF^V600E-mutant anaplastic thyroid cancer, and advanced or progressive medullary thyroid cancer. Longer term efficacy and safety of these treatments have been investigated in multiple real-world studies, demonstrating indispensable complementary value. Hereby, we summarize data from a total of 27 real-world studies with a focus on long-term survival data and rare but life-threatening adverse effects. An overall picture of current real-world study was drawn, and integrated experience of multiple centers would be helpful to clinical practice and further research.

Prognosis of radiotherapy in medullary thyroid carcinoma patients without distant metastasis

Background

Medullary thyroid carcinoma (MTC) is an advanced disease with a poor prognosis. Although radiotherapy is widely utilized to treat MTC, it is still controversial. MTC patients without distant metastases have not been investigated to explore indications for adjuvant radiotherapy. This study aims to investigate the impact of radiotherapy on the survival of MTC patients without distant metastases.

Methods

Data of MTC patients without distant metastasis who underwent total thyroidectomy between 2010 and 2015 were obtained from the Surveillance, Epidemiology and End Results (SEER) database. Propensity score matching was performed to analyze the relationship between radiotherapy and cancer-specific survival (CSS).

Results

Seventy-four of 718 MTC patients without distant metastases received radiotherapy and underwent total thyroidectomy. A total of 148 patients were screened via propensity score matching analysis. Multivariate Cox regression indicated that factors including age, sex, radiotherapy and chemotherapy were independent predictors of CSS. Based on these factors, MTC patients without distant metastasis were classified into two risk groups using a nomogram and risk classification system. The C-index of the nomogram was 0.791. The calibration curves showed good consistency of CSS between the actual observation and the nomogram prediction, and decision curve analysis (DCA) showed great clinical usefulness of the nomogram. The three-year CSS of the radiotherapy group was 85.3%, and that of the surgery group was 95%. Particularly, compared with the surgery group, the three-year CSS of subgroups of the radiotherapy group, including male patients and those aged >48 years, was decreased.

Conclusions

Radiotherapy results in worse CSS for MTC patients without distant metastases. To maximize benefits, decisions about individual radiotherapy should weigh its advantages and disadvantages.

Evaluation of Survival and Postoperative Radiation Among Patients with Advanced Medullary Thyroid Carcinoma: An Analysis of the National Cancer Database

BACKGROUND

This study compared survival between patients who had medullary thyroid cancer (MTC) treated with surgery alone and patients who underwent surgery and radiation (SRT).

METHODS

Patients from the National Cancer Database (NCDB) with a diagnosis of stage 3 or 4 MTC, lymph node disease, and no distant metastases between 2008 and 2016 were studied. Kaplan-Meier analyses and log-rank statistics were used to estimate and compare overall survival between patients treated with surgery alone and those treated with SRT. Mutlivariable Cox proportional hazards models and propensity-matching were used to adjust for confounding and selection bias.

RESULTS

Among 1370 patients, 1112 (81%) received surgery alone, and 258 (19%) received SRT. The hazard ratio for mortality in the SRT group was 1.784 (95% confidence interval [CI] 1.313-2.43) after multivariable adjustment for confounding variables. Furthermore, SRT remained associated with a higher mortality rate (p < 0.008) after propensity-matching in an effort to adjust for selection bias.

CONCLUSIONS

This analysis of NCDB patients showed that SRT is associated with a significantly higher mortality rate among patients treated for stage 3 or 4 IV MTC with positive lymph node disease. Although this observation can be attributed to unmeasured confounders or selection bias, the cause for the profound survival differences deserves prospective evaluation, especially as adjuvant therapies for this disease continue to evolve.

State of the art and future directions in the systemic treatment of medullary thyroid cancer

PURPOSE OF REVIEW

Systemic treatment is the only therapeutic option for patients with progressive, metastatic medullary thyroid cancer (MTC). Since the discovery of the rearranged during transfection (RET) proto-oncogene (100% hereditary, 60-90% sporadic MTC), research has focused on finding effective systemic therapies to target this mutation. This review surveys recent findings.

RECENT FINDINGS

Multikinase inhibitors are systemic agents targeting angiogenesis, inhibiting growth of tumor cells and cells in the tumor environment and healthy endothelium. In the phase III EXAM and ZETA trials, cabozantinib and vandetanib showed progression-free survival benefit, without evidence of prolonged overall survival. Selpercatinib and pralsetinib are kinase inhibitors with high specificity for RET; phase I and II studies showed overall response rates of 73% and 71% in first line, and 69% and 60% in second line treatment, respectively. Although resistance mechanisms to mutation-driven therapy will be a challenge in the future, phase III studies are ongoing and neo-adjuvant therapy with selpercatinib is being studied.

SUMMARY

The development of selective RET-inhibitors has expanded the therapeutic arsenal to control tumor growth in progressive MTC, with fewer adverse effects than multikinase inhibitors. Future studies should confirm their effectiveness, study neo-adjuvant strategies, and tackle resistance to these inhibitors, ultimately to improve patient outcomes.

Outcome of Patients with Locally Advanced Metastatic Medullary Thyroid Cancer and Induction Therapy with Tyrosine Kinase Inhibitors in Slovenia

BACKGROUND

The aim of our retrospective study was to evaluate the outcome of patients with metastatic medullary thyroid cancer (MTC) treated with tyrosine kinase inhibitors (TKIs) and/or chemotherapy with the emphasis on analysis on the cohort treated by induction TKI because of locally advanced metastatic MTC.

METHODS

We analyzed the outcome of 30 patients (21 males, 9 females; median age 63.8 years) with metastatic MTC treated between 2000-2020. Sunitinib was used in 20 patients.

RESULTS

Median progression-free survival on TKI and on chemotherapy was 10.6 (95% CI 7.1-14) months and 3.5 (95% CI 1.4-5.5) months, respectively. Median overall survival from diagnosis and from metastasis presentation was 38.2 (95% CI 4.7-71.7) months and 20.9 (95% CI 13.8-27.9) months, respectively. Eight patients (five females, three males; 58-86 years of age, median age 70 years) were treated with induction TKI because of inoperable locally advanced and metastatic MTC. The response rate to induction TKI was 50%; two patients (25%) had stable disease, and two patients (25%) had progressive disease.

CONCLUSION

Our data support a new paradigm that TKIs may be the first treatment option in selected patients with locally advanced metastatic MTC, followed by locoregional treatment with surgery and/or external beam radiotherapy. Further studies are required to consolidate the presented data.

The Efficacy and Safety of Anlotinib in Neoadjuvant Treatment of Locally Advanced Thyroid Cancer: A Single-Arm Phase II Clinical Trial

Background: Surgery is the primary treatment for locally advanced thyroid cancer. For some cases, R0/R1 resection could not be achieved at initial diagnosis and neoadjuvant treatment would be an option. Anlotinib is a multitarget tyrosine kinase inhibitor, which demonstrated antitumor activity in radioiodine-refractory differentiated thyroid cancer and medullary thyroid cancer. We aimed to evaluate the efficacy and safety of anlotinib in locally advanced thyroid cancer in the neoadjuvant setting. Methods: This single-arm phase II study investigated the efficacy and safety of anlotinib (12 mg orally daily, 2 weeks on/1 week off) for 2-6 cycles in patients with locally advanced thyroid cancer in the neoadjuvant setting. The key eligibility criteria included age 14-80 years old; locally advanced thyroid cancer that would benefit from surgery, and at least one measurable lesion. Operable patients received surgery after neoadjuvant treatment. The primary endpoint was objective response rate (ORR). Results: A total of 13 patients were enrolled and received an average of 3.5 cycles of anlotinib treatment. The ORR of anlotinib was 76.9% (95% confidence interval: 46.2-95.0%). The R0/R1 resection rate in the intent-to-treat population was 61.5% and in the per-protocol population was 72.7%. The median time to response was 61.5 days, and the disease control rate at 18 weeks was 92.3%. No patients had blood transfusion or tracheotomy. Most adverse events (AEs) were grade 1 or 2 and tended to discontinue when neoadjuvant treatment ceased. Common AEs of all grades were hypertension (76.9%), hypertriglyceridemia (69.2%), proteinuria (53.8%), thyrotropin increase (53.8%), cholesterol elevation (53.8%), and hand-foot syndrome (38.5%). Conclusions: Anlotinib demonstrated antitumor activity in the neoadjuvant treatment and the majority of patients achieved R0/R1 resection. AEs were consistent with the known anlotinib AE profile. These results suggest that anlotinib neoadjuvant treatment represents a new option for locally advanced thyroid cancer. Clinical Trial Registration Number: NCT04309136.

Discovery, preclinical development, and clinical application of pralsetinib in the treatment of thyroid cancer

INTRODUCTION

The use of targeted drug therapies has substantially increased in the treatment of RET-mutated thyroid and other solid cancers over the last decade. Multi-Kinase Inhibitors (MKI) have been approved by FDA, but limited efficacies and side effects make them uneasy to tolerate. Pralsetinib is an oral highly selective RET inhibitor drug that has been generated and clinically validated to have higher potency and less toxicity.

AREAS COVERED

The present paper offers a brief summary of RET-related thyroid cancer genetics, an overview of the preclinical development of pralsetinib and reviews its clinical validation in the treatment of thyroid cancer.

EXPERT OPINION

Pralsetinib is a new generation oral treatment that has been approved by the FDA for patients with RET-mutated thyroid cancer. Pralsetinib showed a safer toxicity profile compared to previously approved MKI, probably due to lower inhibition of other tyrosine kinases, especially VEGFR. The approval study ARROW trial showed that patients with RET-mutant medullary thyroid cancer had a better overall response rate to pralsetinib compared to standard-of-care treatments. Additional clinical trials or data enrichment of existing databases are desirable in order to verify and further describe the clinical benefit of pralsetinib in such patients to fully understand its pharmacological profile.

Medullary thyroid carcinoma

PURPOSE OF REVIEW

To summarize recent developments in the diagnosis and management of patients with medullary thyroid cancer (MTC), with a focus on pathogenesis, systemic therapy, and future directions.

RECENT FINDINGS

The addition of mutational analysis to cytological assessment of thyroid nodules has improved the diagnostic accuracy of MTC. The discovery of new genomic alterations and overexpression of certain factors allows for improved prognostication in MTC and provides potentially new therapeutic agents. New data suggest that tumor environment may be more immunogenic than previously thought in a subset of MTCs with identification of a new MTC-specific antigen leading to a revival of investigating immune-based therapy for this disease. The newly approved selective rearranged during transfection (RET0-inhibitors, selpercatinib and pralsetinib, offer promising results, and tolerability for patients with RET-mutated MTC; however, the development of resistance mechanisms may be problematic.

SUMMARY

MTC has witnessed remarkable advancements in recent years. Our new understanding of some of the driver mutations in MTC allows for therapeutics with more tolerable adverse event profiles. However, there is still a need for more effective treatment strategies for subsets of patients without actionable mutations and for those who develop resistance to currently available therapies.

Medullary thyroid carcinoma: recent advances in identification, treatment, and prognosis

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that represents <5% of all thyroid malignancies and is generally more aggressive than differentiated thyroid cancer. The aim of this study is to provide an update, through review of clinical studies of patients with MTC published between January 1, 2016, and June 1, 2021, on recent advances in the diagnosis and treatment of MTC. This review focuses on updates in biochemical testing, imaging, hereditary disease, surgical management, adjuvant therapies, and prognosis. Recent advances reviewed herein have sought to diagnose MTC at earlier stages of disease, predict when patients with a hereditary syndrome may develop MTC, use functional imaging to assess for distant metastases, perform optimal initial surgery with appropriate lymphadenectomy, employ targeted systemic therapies for patients with progressive metastatic disease, and better predict patient-specific outcomes.

Neoadjuvant selpercatinib for advanced medullary thyroid cancer

Background

Targeted kinase inhibitors have been increasingly utilized in the treatment of advanced medullary thyroid cancer (MTC) over the last decade. Recently, highly potent next generation selective RET inhibitors have been clinically validated, and selpercatinib was recently Food and Drug Administration (FDA)‐approved for advanced MTC. The advent of highly selective, potent RET inhibitors is broadening the treatment options for patients with RET‐mutated cancers.

Methods

We report the first published case of neoadjuvant selpercatinib followed by surgery for a patient with initially unresectable, widely metastatic, RET‐mutated MTC who was treated on a single patient protocol.

Results

After greater than 50% RECIST response, the patient underwent complete surgical resection followed by selpercatinib resumption. He remains locoregionally disease‐free 21 months after starting therapy with stable metastatic disease (after initial partial response); and calcitonin/CEA continue to decline.

Conclusion

This novel treatment strategy for locoregionally advanced RET‐mutated MTC warrants further study in clinical trials.