Medullary Thyroid Cancer: Updates and Challenges

Preoperative prediction of Ki-67 expression in medullary thyroid carcinoma based on ultrasonographic features: a 10-year retrospective study

PURPOSE

To identify ultrasonographic features that help distinguish Ki-67 expression levels in patients with medullary thyroid carcinoma (MTC).

MATERIALS AND METHODS

A total of 210 patients (245 nodules) with pathological diagnosis of MTC were included in this retrospective study between January 2013 and April 2024. Based on preoperative clinical and ultrasonographic features, univariate analysis and multivariate logistic regression analysis were performed to determine the risk factors associated with Ki-67 ≥ 5 %. A prediction model was subsequently established to evaluate the differential diagnostic performance of Ki-67 by the area under the curve (AUC).

RESULTS

Among the 210 MTC patients (245 nodules), 35 patients (41 nodules) exhibited high Ki-67 expression (Ki-67 ≥ 5 %), while 175 patients (204 nodules) had low Ki-67 expression (Ki-67 < 5 %). There were no significant differences in age, sex, body mass index (BMI), preoperative calcitonin and preoperative CEA levels between the two groups (P > 0.05). Multivariate analysis of the nodules in the two groups revealed that the ultrasound features, including location in the upper or middle region, tumor size > 2.15 cm, and markedly hypoechoic were independent risk factors for high Ki-67 expression. A prediction model was established with the AUC of 0.812 (95 % CI 0.743-0.882).

CONCLUSIONS

Compared to the low Ki-67 expression group, Ki-67 ≥ 5 % group were more likely to exhibit the ultrasound characteristics of location in the upper or middle region, tumor size > 2.15 cm, and markedly hypoechoic. The prediction model demonstrated preferable diagnostic value.

Post-marketing safety of pralsetinib: a real-world disproportionality analysis based on the FDA adverse event reporting system database

BACKGROUND

Pralsetinib is a novel rearranged during transfection (RET) inhibitor that is approved for treating non-small cell lung cancer and thyroid cancer. Although clinical trials have established its efficacy, real-world data on its safety profile remain limited.

AIM

This study aimed to analyze pralsetinib-related adverse events (AEs) reported in the Food and Drug Administration adverse event reporting system (FAERS) database to identify potential safety signals.

METHOD

We conducted a retrospective pharmacovigilance analysis using FAERS database from Q3 2020 to Q2 2024. After deduplication, disproportionality analysis was performed using four algorithms: reporting odds ratio (ROR), proportional reporting ratio, Bayesian confidence propagation neural network, and empirical Bayes geometric mean.

RESULTS

A total of 1064 pralsetinib-related reports were identified, encompassing 3608 AEs. The most common AEs were hypertension (n = 80), asthenia (n = 79), anemia (n = 65), white blood cell count decreased (n = 63), and constipation (n = 58). We also detected new and unexpected AE signals, including blood calcitonin increased (ROR: 853.54), myocardial necrosis marker increased (ROR: 201.79), cystitis bacterial (ROR: 134.84), fungal foot infection (ROR: 51.83), pulmonary tuberculosis (ROR: 39.5), and myocardial injury (ROR: 30.36). Additionally, hypertension was more prevalent among female patients (Female/Male = 53/19, ROR: 1.8 [1.06-3.05]) and olderpatients (≥ 65/ < 65 = 34/18, ROR: 1.8 [1.01-3.2]).

CONCLUSION

Our study identified some known and new significant AE signals associated with pralsetinib, emphasizing the importance of continued pharmacovigilance. While the findings provide valuable insights for clinical practice, further validation through large-scale prospective studies is needed.

Primary tumor resection with or without neck lymph node dissection as a viable initial therapy for medullary thyroid carcinoma with distant metastasis

OBJECTIVE

Patients with distant metastatic medullary thyroid carcinoma (DMMTC) often undergo primary tumor resection (PTR) with or without neck lymph node dissection (NLND) before systemic therapy. However, whether these patients benefit from treatment remains unclear.

METHODS

Patients with DMMTC were identified from the Surveillance, Epidemiology, and End Results (SEER) database between 2010 and 2020. The overall survival (OS) and disease-specific survival (DSS) were established by Kaplan-Meier curves and were compared using the log-rank test or two-stage test between different treatment modalities (surgery, non-surgery) after propensity score matching (PSM). We also analyzed the effects of surgical and non-surgical treatments on the OS and DSS of patients stratified by TNM stages T1-2 and T3-4 in this cohort.

RESULTS

Among the 2336 patients with medullary thyroid carcinoma from the SEER database, 186 were diagnosed with DMMTC, with an average follow-up period of 28.12 months. Pairwise analysis after PSM revealed that the surgery group had a significantly improved survival rate compared to the non-surgery group (OS p = 0.00039, DSS p = 0.001). The survival advantages of the above-mentioned surgery group were maintained when stratified by stages T1-2 and T3-4.

CONCLUSION

Our results demonstrate that PTR with or without NLND, as an initial therapy, can benefit the survival rate of patients with DMMTC.

Tumor-Infiltrating Lymphocytes Assessed Using the International TILs Working Group System Are Not Prognostic in Medullary Thyroid Cancer

Background: Tumor-infiltrating lymphocytes (TILs) are a protective prognostic factor in several solid tumors and predict response to immune checkpoint inhibitor therapy. The prognostic impact of TILs in medullary thyroid cancer (MTC) is poorly understood. Materials and Methods: In this retrospective cohort study, we assessed the TILs profile of primary MTC tumors using the International TILs Working Group system and correlated this with clinicopathological prognostic variables, including the International Medullary Thyroid Cancer Grading System (IMTCGS) grade and survival outcomes. Results: We identified 71 patients with primary MTC tumors who were treated surgically between 1995 and 2016 at the Royal North Shore Hospital in Sydney, Australia. The median (interquartile range) duration of follow-up was 69 (90) months. Using the ITWG system, all patients with MTC had low TILs, with a median (range) of 3% (0-10%). This group was further subdivided into "very low" (0-4%) and "low" (5-10%), and on Cox regression analysis, increasing TILs were associated with increased local recurrence (log-rank p = 0.022, odds ratio [OR] 1.94 [confidence interval or CI 0.61-6.16], p = 0.26), reduced disease-specific survival (log-rank p = 0.015, OR 5.11 [CI 1.01-26.0], p = 0.049), and a trend to decreased distant metastasis-free survival (log-rank p = 0.14). When examining the association between TILs and other prognostic factors, only "high IMTCGS grade" was significantly associated with increased TILs (OR 7.29 [CI 1.21-43.90], p = 0.015). In the multivariable logistic regression analysis, there was no significant association between TILs and local recurrence or disease-specific survival. Conclusions: In our study, the prognostic value of TILs in MTC was limited. Even high-grade MTC can be considered an immune quiescent tumor, and the adverse prognostic factors associated with higher grade tumors outweigh the marginal increase in immune recognition associated with a slight increase in TILs. The low level of TILs in MTC and their lack of correlation with survival suggest that immune checkpoint inhibitor therapy may not be effective.

Development and validation of risk prediction models for permanent hypocalcemia after total thyroidectomy in patients with papillary thyroid carcinoma

Hypocalcemia is a common complication and can be permanent in patients following total thyroidectomy (TT). The aim of this study was to identify factors associated with permanent hypocalcemia and to develop a validated risk prediction model for permanent hypocalcemia to assist surgeons in the appropriate follow-up of high-risk patients regarding supplemental therapy. We included data of 92 patients with papillary thyroid carcinoma (PTC) undergoing TT who were randomly allocated in a 7:3 ratio to a training set (n = 65) and validation set (n = 27). Univariate and multivariate logistic regression analyses revealed significant correlations of permanent hypocalcemia with parathyroid hormone (PTH) at postoperative month 1 (IM PTH), IM calcium (Ca), and IM phosphorus (P). These variables were constructed two models. Model 1 used the three indicators listed above; model 2 also included tumor, node, metastasis staging. The receiver operating characteristic (ROC) curve analysis showed that the areas under the curve (AUC) for models 1 and 2 were high for both the training set (0.905/0.913) and the validation set (0.894/0.800). Calibration curves showed good agreement between the incidence of permanent hypocalcemia estimated using the predictive models and the actual incidence. Model 1 may be more concise and convenient for clinical use.

Medullary Thyroid Carcinoma and Clinical Outcomes in Heterozygous Carriers of the RET K666N Germline Pathogenic Variant

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor of the thyroid parafollicular C-cells associated with activating mutations in the rearranged during transfection (RET) kinase proto-oncogene. We report the clinical outcomes of a family with a rare germline RET K666N pathogenic variant discovered incidentally by genetic testing performed for breast cancer risk stratification in an asymptomatic 24-year-old woman. Subsequent genetic testing identified the same pathogenic variant in her 21-year-old sister, 60-year-old father, and 84-year-old paternal grandmother. The proband and her sister had no biochemical or imaging evidence of MTC. The 60-year-old father had mildly elevated serum calcitonin and multiple thyroid nodules on ultrasound. Fine-needle aspirate thyroid biopsy cytology suggested MTC so he underwent total thyroidectomy. Surgical pathology demonstrated bilateral subcentimeter foci of MTC and C-cell hyperplasia. The 84-year-old grandmother was also found to have multiple thyroid nodules and elevated calcitonin but declined further evaluation. There was no biochemical evidence of other multiple endocrine neoplastic type 2 (MEN2)-associated tumors (ie, parathyroid adenoma, pheochromocytoma) in the family. These data, along with prior rare reports in the literature, suggest that monoallelic germline RET K666N pathogenic variants carry a risk of familial MTC that demonstrate age-dependent expressivity but low penetrance of other MEN2 tumors in affected individuals.

Mechanisms of resistance to RET-directed therapies

The association between RET and multiple endocrine neoplasia type 2 was established in 1993 and remains one of the very few oncogenes for which distinct phenotypes (medullary thyroid cancer or pheochromocytoma) are associated with the same hot-spot variants occurring in either germline or somatic DNA. Somatic RET fusion events have also been described in several cancers, including papillary thyroid cancer, non-small-cell lung cancer, breast cancer, salivary gland cancer and pancreatic cancer. Highly selective RET inhibitors have improved outcomes in RET-altered cancers and have been well-tolerated. Nevertheless, primary and acquired drug resistance has been observed, arising from distinct genomic alterations either in RET (on-target resistance) or via alternate oncogenic pathways (bypass resistance). The same mechanisms of resistance have been observed across multiple cancer types, which implies RET-altered cancers evolve away from RET addiction via stochastic subclonal events. Understanding these mechanisms is crucial for identifying therapeutic opportunities to overcome resistance. Successful treatment targeting bypass oncogenes has been reported in several instances, at least for short-term outcomes; in contrast, although several compounds have been reported to overcome on-target RET alterations, none have yet been translated into routine clinical practice and this remains an area of urgent clinical need.

Effects of Food on the Pharmacokinetics and Safety of HA121-28 Tablet, a Novel Multi-Targeting Tyrosine Kinase Inhibitor, in Healthy Chinese Subjects: A Phase I Clinical Trial

Purpose

HA121-28, a novel multi-targeting tyrosine kinase inhibitor, has dual efficacy against tumor growth and neovascularization. The objectives of this study were to assess the effect of high-fat and high-calorie food on the pharmacokinetic (PK) profile and safety of HA121-28 tablet in healthy subjects.

Patients and Methods

A single-dose, randomized, open-label, two-period, crossover-designed phase I clinical trial was conducted. Subjects received 200 mg HA121-28 in the fasted state or with high-fat and high-calorie breakfast. The effects of high-fat and high-calorie food on the PK profile and safety of HA121-28 were evaluated by using noncompartmental analysis and whole-process safety assessment.

Results

Twenty subjects were successfully completed the trial. The geometric mean ratios (GMRs) for the peak concentration in plasma (Cmax), area under the curve from zero to the time point (AUClast), and area under the curve from zero to infinite (AUCinf) postprandially versus fasted were 108.45% (98.51% - 119.40%), 105.23% (100.25% - 110.47%), and 104.14% (97.41% - 111.34%), respectively. The majority of reported adverse events were graded as either level 1 or 2 in severity and recovered spontaneously without any interventions.

Conclusion

The exposure of HA121-28 was not significantly affected by the high-fat and high-calorie food. The clinical application of HA121-28 tablet can be recommended for use in both fasted and postprandial states.

Anterior mediastinal tracheostomy - a salvage procedure for tracheal necrosis after thyroidectomy for medullary thyroid cancer: a case-report

A 34-year-old male patient with recently diagnosed with medullary thyroid carcinoma underwent total thyroidectomy and radical neck dissection, requiring sharp dissection to separate the tumour from the trachea. He required post operative intubation due to bilateral vocal cord paralysis. He developed ischaemic necrosis of the upper two thirds of the trachea presenting with marked surgical emphysema and an infective wound. The wound was opened, drained and an endotracheal tube was negotiated through the sloughed trachea into the distal intrathoracic trachea with the cuff inflated just above the carina. This complication was managed with total pharyngo-laryngectomy, anterior deep mediastinal tracheostomy and construction of a neo-cervical oesophagus with a free lateral thigh fascio-cutaneous flap. This case highlights the potential complications of a procedure, perseverance, collaboration amongst various disciplines and teamwork for treating a rare and complex condition. The patient was discharged and has had an excellent recovery with good quality of life over two years of follow up.

What Is New in Diagnostics and Management of Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC) is a rare neoplasm originating from parafollicular C cells. It secretes calcitonin (Ctn), a highly sensitive and specific tumor marker, which allows for early diagnosis and defines postoperative cure or persistence/recurrence of MTC. Germline mutations in the RET proto-oncogene are responsible for the development of MTC in MEN2. Somatic RET mutations modify the behavior of MTC and are a target for systemic therapy with selective RET inhibitors. Recent advances in preoperative immunohistochemistry and molecular diagnostics in biopsies achieved by fine needle aspiration significantly improves diagnosis and allows classification in low and high risk MTC with important implications for treatment and prognosis. This personalized approach enables a less aggressive surgery in low risk MTC patients, reduces the incidence of complications and improves quality of life. Risk stratification in MEN2 patients based on genotype-phenotype correlation of the different RET mutations allows cure by personalized thyroidectomy. Postoperative imaging in patients with persistent or recurrent MTC with PET/CT using different radiopharmaceuticals proved to be sensitive and accurate in detecting MTC recurrences/metastases and assesses their biological and clinical aggressiveness. Molecular genetic classification of tumors enables personalized systemic therapies with multikinase inhibitors or selective RET inhibitors in patients with advanced metastasized and progressive disease. Despite the recent progress in diagnosis and treatment, confirmation of these new procedures and standardization of these approaches in MTC are required.

DLK1 Is Associated with Stemness Phenotype in Medullary Thyroid Carcinoma Cell Lines

Medullary thyroid carcinoma (MTC) is a rare and aggressive tumor, often requiring systemic treatment in advanced or metastatic stages, where drug resistance presents a significant challenge. Given the role of cancer stem cells (CSCs) in cancer recurrence and drug resistance, we aimed to identify CSC subpopulations within two MTC cell lines harboring pathogenic variants in the two most common MEN2-associated codons. We analyzed 15 stemness-associated markers, along with well-established thyroid stem cell markers (CD133, CD44, and ALDH1), a novel candidate (DLK1), and multidrug resistance proteins (MRP1 and MRP3). The ability to efflux the fluorescent dye Hoechst 3342 and form spheroids, representing CSC behavior, was also assessed. MZ-CRC-1 cells (p.M918T) displayed higher expressions of canonical markers, DLK1, and MRP proteins than TT cells (p.C634W). MZ-CRC-1 cells also formed more spheroids and showed less dye accumulation (p < 0.0001). Finally, we observed that DLK1+ cells (those expressing DLK1) in both cell lines exhibited significantly higher levels of stemness markers compared to DLK1- cells (those lacking DLK1 expression). These findings underscore DLK1's role in enhancing the stemness phenotype, providing valuable insights into MTC progression and resistance and suggesting potential therapeutic implications.

Defining the Functional Sensitivity for the Siemens Atellica Calcitonin Assay: Insight From a Single-Center Study

BACKGROUND

Detectable, and especially rising postthyroidectomy serum calcitonin and carcinoembryonic antigen levels, as per American Thyroid Association guidelines, indicate potential disease presence, requiring frequent calcitonin measurement or imaging for early detection of persistent or recurrent medullary thyroid carcinoma. Thus, defining the clinical cutoff value of detection of calcitonin assays relative to imaging and clinical status is crucial for patient care. This study aimed to evaluate postoperative calcitonin levels using the new Siemens Atellica assay system to determine the most appropriate levels for clinical decision-making.

METHODS

A retrospective analysis was conducted using Siemens Atellica for calcitonin testing on 56 samples from 40 patients between September 27, 2022 and August 11, 2023. Only calcitonin results performed at least 3 months post-total thyroidectomy were included. Imaging studies, within 6 months of the calcitonin report, were assessed. Carcinoembryonic antigen results were also reviewed.

RESULTS

Precision analysis at 2.94 and 5.24 pg/mL revealed coefficients of variation at 16.49% and 8.87%, respectively. For the evidence of post-total thyroidectomy persistent or recurrent medullary thyroid carcinoma confirmed by imaging, using a 1.89 pg/mL cutoff for calcitonin yielded 43% sensitivity and 67% specificity. Using a 5.00 pg/mL cutoff resulted in 0% sensitivity and 100% specificity.

CONCLUSIONS

Our findings indicate the potential suitability of a 5 pg/mL calcitonin cutoff on the Siemens Atellica platform for evaluating tumor persistence or recurrence in post-thyroidectomy patients in our institution. However, individual laboratories should establish their own clinical cutoff value when evaluating calcitonin levels for monitoring tumor recurrence post-thyroidectomy.

Survival Outcome and Optimal Candidates of Primary Tumor Resection for Patients With Metastatic Medullary Thyroid Cancer

CONTEXT

Medullary thyroid cancer (MTC) often exhibits aggressive growth with distant organ metastasis, leading to poor survival.

OBJECTIVE

The question of whether primary tumor resection (PTR) is beneficial for patients with metastatic MTC remains a subject of debate. In this study, we evaluated the prognostic significance of organ-specific metastases and the number of metastatic organs in these patients, and we also conducted an analysis to determine the therapeutic value of PTR in managing this rare malignancy.

MATERIALS AND METHODS

Patients initially diagnosed with metastatic MTC were identified within the Surveillance, Epidemiology, and End Results database. Univariable and multivariable Cox proportional hazards regression models were performed to identify survival predictors. Survival outcomes were calculated using the Kaplan-Meier method and compared using the log-rank tests.

RESULTS

A total of 186 patients with metastatic MTC at initial diagnosis from 2010 to 2020 were included. Bone, lung, and liver were the most common metastatic organs. Patients with brain metastasis had significantly worse overall survival (P = .007) and cancer-specific survival (P = .0013). Among all patients, 105 (56.45%) underwent PTR, and this group showed reduced overall mortality and cancer-specific mortality (all P < .05). When analyzing different metastatic patterns, PTR significantly lowered the risk of overall mortality and cancer-specific mortality for patients with bone, lung, liver, or distant lymph node involvement (all P < .05). Additionally, among patients with 1 or 2 metastases, those undergoing surgical resection were significantly associated with favorable overall survival (P = .008) and cancer-specific survival (P = .0247).

CONCLUSION

PTR may confer therapeutic benefits for carefully selected individuals with metastatic MTCs. To integrate these insights into clinical decision-making settings, it is imperative to undertake multicenter prospective studies in the future.

Holomics and Artificial Intelligence-Driven Precision Oncology for Medullary Thyroid Carcinoma: Addressing Challenges of a Rare and Aggressive Disease

Background/Objective: Medullary thyroid carcinoma (MTC) is a rare yet aggressive form of thyroid cancer comprising a disproportionate share of thyroid cancer-related mortalities, despite its low prevalence. MTC differs from other differentiated thyroid malignancies due to its heterogeneous nature, presenting complexities in both hereditary and sporadic cases. Traditional management guidelines, which are designed primarily for papillary thyroid carcinoma (PTC), fall short in providing the individualized care required for patients with MTC. In recent years, the sheer volume of data generated from clinical evaluations, radiological imaging, pathological assessments, genetic mutations, and immunological profiles has made it humanly impossible for clinicians to simultaneously analyze and integrate these diverse data streams effectively. This data deluge necessitates the adoption of advanced technologies to assist in decision-making processes. Holomics, which is an integrated approach that combines various omics technologies, along with artificial intelligence (AI), emerges as a powerful solution to address these challenges. Methods: This article reviews how AI-driven precision oncology can enhance the diagnostic workup, staging, risk stratification, management, and follow-up care of patients with MTC by processing vast amounts of complex data quickly and accurately. Articles published in English language and indexed in Pubmed were searched. Results: AI algorithms can identify patterns and correlations that may not be apparent to human clinicians, thereby improving the precision of personalized treatment plans. Moreover, the implementation of AI in the management of MTC enables the collation and synthesis of clinical experiences from across the globe, facilitating a more comprehensive understanding of the disease and its treatment outcomes. Conclusions: The integration of holomics and AI in the management of patients with MTC represents a significant advancement in precision oncology. This innovative approach not only addresses the complexities of a rare and aggressive disease but also paves the way for global collaboration and equitable healthcare solutions, ultimately transforming the landscape of treatment and care of patients with MTC. By leveraging AI and holomics, we can strive toward making personalized healthcare accessible to every individual, regardless of their economic status, thereby improving overall survival rates and quality of life for MTC patients worldwide. This global approach aligns with the United Nations Sustainable Development Goal 3, which aims to ensure healthy lives and promote well-being at all ages.

The Long-Term Cure of Patients With Hereditary Medullary Thyroid Carcinoma: 40 Years of Follow-Up in a Single Center

BACKGROUND

The cure rate of patients with hereditary medullary thyroid carcionoma (MTC) can be decisively improved by screening for elevated calcitonin (Ctn) levels and RET gene mutations in patients from families affected by multiple endocrine neoplasia type 2 (MEN2), followed by prophylactic thyroidectomy in persons with mutated RET genes. In this long-term observational study, we investigated whether postoperative cures are indeed maintained decades after the procedure.

METHODS

From 1979 to 2021, 277 patients with MEN2 who underwent thyroidectomy were observed postoperatively for 14.4 ± 10.3 years (mean, standard deviation). They were classified as either cured or not cured depending on the last measured serum Ctn level (cured, Ctn < 10 pg/mL or < 2 pg/mL; not cured, Ctn ≥ 10 pg/mL). Depending on their RET mutation status, they were categorized as moderate, high, or highest risk (121, 130, and 26 patients, respec - tively).

RESULTS

154 patients (55.6%) obtained a long-term cure (Ctn <10 pg/mL). The median age at surgery was 27, 14, and 4 years in patients at moderate, high, and highest risk. All 52 patients who had undergone prophylactic thyroidectomy before the age of 6 years, 9 years, or 6 months had a Ctn level below 2 pg/mL and were cured at the end of the follow-up period. In a multivariable analysis, prognostic factors for a long-term cure were a lower tumor stage and, by tendency, classification as belonging to the moderate as opposed to the highest-risk group.

CONCLUSION

In patients receiving an early diagnosis of MEN2 via family screening, prophylactic thyroidectomy taking into account the RET mutation risk group can achieve a long-term cure of MTC with undetectable serum Ctn levels.

La prise en charge des cancers médullaires de la thyroïde en 2024

MANAGING MEDULLARY THYROID CARCINOMA IN 2024: Medullary thyroid carcinoma is a rare neuroendocrine thyroid cancer with a heterogeneous prognosis which has the particularity of being associated with a RET gene mutation, germline in 20-25% of cases in the context of multiple endocrine neoplasia type 2 (NEM2), and somatic in 70% of sporadic cases. It is often diagnosed on a thyroid nodule or in the context of genetic screening. Calcitonin is a biological marker, used for diagnosis, monitoring of therapeutic response and prognostic evaluation. The only curative treatment is surgery for localized disease. The extent must be carefully assessed, particularly in terms of calcitonin levels and imaging, and carried out by an expert surgeon. The prognosis of locally advanced or metastatic disease is highly heterogeneous. Histological factors, such as high grade, or biological factors, such as calcitonin doubling time, can help assess prognosis. The development of multi-kinase inhibitors cabonzantinib and vandetanib, and RET-targeted inhibitors selpercatinib, has completely changed the therapeutic arsenal for advanced disease, but their prescription is reserved to progressive disease with high tumor volume or to symptomatic disease inaccessible to local treatment in expert centers from the ENDOCAN-TUTHYREF network. Active surveillance is the alternative of choice for slowly progressing disease.

Coexisting Medullary and Papillary Thyroid Carcinomas: A Case of Dual Neoplasia With a High Risk of Misdiagnosis

The simultaneous occurrence of more than two types of neoplasms is rare due to their significant phenotypic differences. Thyroid carcinoma is regularly associated with genetic alterations and endocrine syndromes. However, the etiology of the forms of papillary thyroid carcinoma (PTC)/medullary thyroid carcinoma (MTC) is still not fully understood. We present the case of a 60-year-old male with no significant history of thyroid disease who presented with dysphonia. Left vocal cord paralysis and a cervical tumor lesion were observed. A mixed medullary/papillary carcinoma was diagnosed. Surgical resection of the mediastinal tumor and hemithyroidectomy revealed a poorly differentiated blue cell MTC, with a tumor size of 6.5 x 6.4 x 4.4 cm and a Ki-67 proliferation index of 10%. The tumor was positive for cytokeratin AE1/AE3, carcinoembryonic antigen, synaptophysin, chromogranin, thyroid transcription factor 1 (TTF-1), S-100, and calcitonin. Metastasis was identified in a lymph node at the mediastinum, supporting a diagnosis of usual-type papillary thyroid carcinoma, with positivity for cytokeratin AE1/AE3, thyroglobulin, and TTF-1. Genetic tests related to hereditary cancer (Gencell Pharma, Bogotá, Columbia) were negative. The simultaneous presence of MTC and PTC in a patient is a rare event. The clinical characteristics and biological behavior of these cancer types can vary. The prognosis is directly related to the stage at presentation and the condition at the time of diagnosis.

Unusual Presentation of Metastatic Medullary Thyroid Cancer Involving Bone Marrow, Kidneys, and Adrenal Gland: A Literature Review Based on a Case Report

BACKGROUND

Medullary thyroid cancer (MTC) is one of the rare neuroendocrine malignancies. This cancer is hereditary in approximately 20% of cases. Although lymph node (LN) metastasis is prevalent in MTC, distant metastasis is not commonly seen in these patients. The most common locations for metastasis are the lungs, liver, and bones. This study presents an extremely rare MTC metastasis to bone marrow (BM) and adrenal gland, which has not been reported before.

CASE

The patient was a 50-year-old man with a diagnosis of MTC and total thyroidectomy 2 months before his presentation. He came to the emergency department (ED) complaining of dyspnea, diffuse bone pain, nonbloody diarrhea, and abdominal cramps starting in the last month before. Initial treatment with intravenous fluid infusion and loperamide, due to the provisional diagnosis of infectious diarrhea, was ineffective. Further assessments revealed severe pancytopenia and a massive tumor above the left kidney. Bone marrow aspiration (BMA) and biopsy (BMB) led to the diagnosis of invasive metastasis of the MTC to the BM and the left adrenal gland. In the initial evaluations, his COVID-19 test became positive, and despite all efforts, his condition deteriorated, and he died 5 days after admission due to respiratory distress.

CONCLUSION

Most MTC cases present with thyroid nodules in the initial steps and are confined to the thyroid gland or the adjacent LNs. These cases are mostly cured by thyroidectomy and LN dissection. This neuroendocrine cancer infrequently becomes aggressive and involves other parts of the body. However, involving BM or adrenal gland has been scarcely reported. Due to ineffective red and white blood cell production, BM metastasis can cause pancytopenia and, consequently, pallor, fatigue, dyspnea, and susceptibility to infections. High calcitonin levels can also cause diarrhea. The initial diagnosis is mostly with neck ultrasound (US) and fine needle aspiration (FNA). Total thyroidectomy is the main therapeutic option for these patients. Calcitonin and carcinoembryonic antigen (CEA) are sensitive indicators of recurrence or remaining tumors, which might be helpful for the initial diagnosis and postoperation follow-up. Although extremely rare, invasive metastasis of MTC might involve unusual body organs such as the BM or adrenal glands. In cases of unjustifiable pancytopenia or adrenal dysfunction in MTC-positive patients, these possibilities should be considered and ruled out by some specific evaluations, such as bone marrow biopsy and contrast-enhanced imaging.

Survival in medullary thyroid carcinoma patients who fail to achieve a biochemical cure: implications of postoperative 1-month calcitonin levels and targeted therapy

PURPOSE

The survival rate of patients with medullary thyroid carcinoma (MTC) who fail to achieve a biochemical cure after surgery is reduced. This study aimed to investigate the prognostic factors affecting the survival of MTC patients who do not achieve a biochemical cure after surgery.

METHODS

Cox univariate and multivariate proportional hazard models were used to determine the influence of different variables on overall survival (OS). Pearson's chi-square test was used for categorical variables, and paired t-test was used for continuous variables.

RESULTS

In our study of 277 MTC patients treated between 2012 and 2022, there were 96 with raised postoperative 1-month calcitonin (Ct) levels (0-9.52 pg/ml). The overall survival (OS) rates of patients with high postoperative 1-month Ct values at 1, 3, and 5 years were 97.9%, 94.6%, and 86.8%, respectively. The univariate analysis revealed that patients with a postoperative 1-month Ct > 441.9 pg/ml had a greater risk of mortality than patients with postoperative 1-month Ct values ranging from 9.52 to 73.4 pg/ml (p = 0.043). Subsequent analyses revealed that receiving targeted therapy did not improve the OS of patients with distant metastasis among those with high postoperative 1-month Ct values (p = 0.527).

CONCLUSION

This study confirmed that MTC patients who did not achieve biochemical remission after surgery had an increased risk of death when the Ct level was > 441.9 pg/ml 1 month after surgery. Additionally, for MTC patients who have not achieved biochemical remission and have experienced disease progression or distant metastasis after surgery, the use of targeted therapy does not prolong survival.

Mechanisms of resistance to tyrosine kinase inhibitor-targeted therapy and overcoming strategies

Tyrosine kinase inhibitor (TKI)-targeted therapy has revolutionized cancer treatment by selectively blocking specific signaling pathways crucial for tumor growth, offering improved outcomes with fewer side effects compared with conventional chemotherapy. However, despite their initial effectiveness, resistance to TKIs remains a significant challenge in clinical practice. Understanding the mechanisms underlying TKI resistance is paramount for improving patient outcomes and developing more effective treatment strategies. In this review, we explored various mechanisms contributing to TKI resistance, including on-target mechanisms and off-target mechanisms, as well as changes in the tumor histology and tumor microenvironment (intrinsic mechanisms). Additionally, we summarized current therapeutic approaches aiming at circumventing TKI resistance, including the development of next-generation TKIs and combination therapies. We also discussed emerging strategies such as the use of dual-targeted antibodies and PROteolysis Targeting Chimeras. Furthermore, we explored future directions in TKI-targeted therapy, including the methods for detecting and monitoring drug resistance during treatment, identification of novel targets, exploration of dual-acting kinase inhibitors, application of nanotechnologies in targeted therapy, and so on. Overall, this review provides a comprehensive overview of the challenges and opportunities in TKI-targeted therapy, aiming to advance our understanding of resistance mechanisms and guide the development of more effective therapeutic approaches in cancer treatment.

Disease-free survival and the prognostic factors affecting disease-free survival in patients with medullary thyroid carcinoma: a multicenter cohort study

PURPOSE

Despite several factors that may have been associated with poor disease-free survival (DFS) in patients with medullary thyroid carcinoma (MTC), only a few studies have evaluated the prognostic factors affecting DFS in MTC patients. Therefore, this study evaluated the prognostic factors affecting DFS, in a large number of patients with MTC.

METHODS

Patients treated for MTC were retrospectively analyzed. Patients were stratified as having persistent/recurrent disease and no evidence of disease (NOD) at the last follow-up. The factors affecting DFS after the initial therapy and during the follow-up period were investigated.

RESULTS

This study comprised 257 patients [females 160 (62.3%), hereditary disease 48 (18.7%), with a mean follow-up time of 66.8 ± 48.5 months]. Persistent/recurrent disease and NOD were observed in 131 (51%) and 126 (49%) patients, respectively. In multivariate analysis, age > 55 (HR: 1.65, p = 0.033), distant metastasis (HR: 2.41, p = 0.035), CTN doubling time (HR: 2.7, p = 0.031), and stage III vs. stage II disease (HR 3.02, p = 0.048) were independent predictors of persistent/recurrent disease. Although 9 (8%) patients with an excellent response after the initial therapy experienced a structural recurrence, the absence of an excellent response was the strongest predictor of persistent/recurrent disease (HR: 5.74, p < 0.001).

CONCLUSIONS

The absence of an excellent response after initial therapy is the strongest predictor of a worse DFS. However, a significant proportion of patients who achieve an excellent response could experience a structural recurrence. Therefore, careful follow-up of patients, including those achieving an excellent response is essential.

Simultaneous occurrence of papillary thyroid carcinoma, medullary thyroid carcinoma, and lymphoma: A case report

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common type of thyroid cancer, the coexistence of PTC and medullary thyroid carcinoma (MTC) is uncommon. While the simultaneous occurrence of both cancers with small lymphocytic lymphoma (SLL) in lymph nodes with PTC metastasis is very rare. This study presents a unique case of concurrent PTC, MTC, and SLL, highlighting the exceptional rarity of these coexisting tumors.

METHODS

A 75-year-old female with a thyroid tumor underwent total thyroidectomy, bilateral central neck lymph node dissection, and right radical neck lymph node dissection. Histopathological examination revealed a low-grade medullary thyroid carcinoma (MTC) in the left lobe and classical papillary thyroid carcinoma (PTC) in the right lobe, with PTC metastasis in the cervical lymph nodes and concurrent SLL in the affected lymph nodes.

RESULTS

Coexistence of PTC, MTC and SLL in the same patient is rare, there are currently no standardized treatment guidelines due to the limited literature. However, it is essential to consider not only the treatment for each type of tumor but also the potential risks or conflicts associated with the treatments. In the case reported in this paper, the papillary carcinoma invaded the capsule of the right lobe of the thyroid and metastasized to the cervical lymph nodes, warranting radioactive iodine therapy. However, considering the potential negative impact of radioactive iodine on the pre-existing lymphoma, the radioactive iodine therapy was postponed. Meanwhile, constant monitoring of calcitonin and thyroid globulin should be performed to monitor tumor recurrence as was performed in the present case.

CONCLUSION

Since MTC, PTC, and SLL may coexist, patients with PTC deserve careful surveillance for the other disease entities. This case underscores the need for heightened awareness among clinicians, radiologists, and pathologists regarding the possibility of concurrent thyroid tumors and abnormal lymph nodes, guiding comprehensive pre-operative evaluations and postoperative monitoring strategies. This study aims to provide a warning for routine pathological diagnosis and contribute data for related research.

Recent advances in the use of tyrosine kinase inhibitors against thyroid cancer

INTRODUCTION

Oncogenic tyrosine kinases (TK) are enzymes that play a key role in cell growth and proliferation and their mutations can lead to uncontrolled cell growth and development of aggressive cancer. This knowledge has led to the development of new classes of drugs, Tyrosine kinase inhibitors (TKI). They target oncogenic kinases who are associated with advanced radioactive iodine (RAI) refractory TC, which is not able to uptake RAI anymore and/or still grows between consecutive treatments with Iodine 131 (I131).

AREAS COVERED

Since Lenvatinib and Sorafenib approval, several other molecular inhibitors have been studied and then introduced for the treatment of aggressive and refractory thyroid cancer (TC), and, although the development of adverse effects or tumor resistance mechanisms, more and more compounds are still under investigation. The literature search was executed in PubMed and ClinicalTrials.gov to identify relevant articles and clinical trials published until December 2023.

EXPERT OPINION

In the context of clinical trials, driven by the presence of specific molecular mutations or even in the absence of both conditions, systemic therapy TKIs are valuable weapons to be used in patients affected by aggressive forms of TC, waiting for further expansion of the treatment landscape with more efficacious and safer drugs.

Paraneoplastic Diarrhea From Medullary Thyroid Carcinoma Resolved With Yttrium-90 Radioembolization of Liver Metastases

Medullary thyroid carcinoma (MTC) can often have an indolent course despite distant metastatic disease. Additionally, given that metastatic MTC is incurable and systemic therapies have non-negligeable toxicities, localized treatments are often favored in presence of oligo-progressive disease. Transarterial radioembolization (TARE) with yttrium-90 (Y90) has emerged as a safe and efficacious treatment for nonresectable primary and metastatic liver tumors, yet data supporting its use in metastatic MTC are limited. We present the case of a patient with hereditary MTC and large bilobar liver metastases who demonstrated tumor response and resolution of their paraneoplastic diarrhea following TARE with Y90 microspheres.

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).

Antineoplastic Effect of ALK Inhibitor Crizotinib in Primary Human Anaplastic Thyroid Cancer Cells with STRN-ALK Fusion In Vitro

Anaplastic thyroid cancer (ATC) is one of the deadliest human cancers and represents <2% of thyroid carcinomas. A therapeutic target for ATC is represented by anaplastic lymphoma kinase (ALK) rearrangements, involved in tumor growth. Crizotinib is an oral small-molecule tyrosine kinase inhibitor of the ALK, MET, and ROS1 kinases, approved in ALK-positive non-small cell lung cancer. Until now, the effect of crizotinib in "primary human ATC cells" (pATCs) with transforming striatin (STRN)-ALK fusion has not been reported in the literature. In this study, we aimed to obtain pATCs with STRN-ALK in vitro and evaluate the in vitro antineoplastic action of crizotinib. Thyroid surgical samples were obtained from 12 ATC patients and 6 controls (who had undergone parathyroidectomy). A total of 10/12 pATC cultures were obtained, 2 of which with transforming STRN-ALK fusion (17%). Crizotinib inhibited proliferation, migration, and invasion and increased apoptosis in 3/10 pATC cultures (2 of which with/1 without STRN-ALK), particularly in those with STRN-ALK. Moreover, crizotinib significantly inhibited the proliferation of AF cells (a continuous cell line obtained from primary ATC cells). In conclusion, the antineoplastic activity of crizotinib has been shown in human pATCs (with STRN-ALK) in preclinical studies in vitro, opening the way to future clinical evaluation in these patients.

MicroRNAs in thyroid cancer with focus on medullary thyroid carcinoma: potential therapeutic targets and diagnostic/prognostic markers and web based tools

This review aimed to describe the inculpation of microRNAs (miRNAs) in thyroid cancer (TC) and its subtypes, mainly medullary thyroid carcinoma (MTC), and to outline web-based tools and databases for bioinformatics analysis of miRNAs in TC. Additionally, the capacity of miRNAs to serve as therapeutic targets and biomarkers in TC management will be discussed. This review is based on a literature search of relevant articles on the role of miRNAs in TC and its subtypes, mainly MTC. Additionally, web-based tools and databases for bioinformatics analysis of miRNAs in TC were identified and described. MiRNAs can perform as oncomiRs or antioncoges, relying on the target mRNAs they regulate. MiRNA replacement therapy using miRNA mimics or antimiRs that aim to suppress the function of certain miRNAs can be applied to correct miRNAs aberrantly expressed in diseases, particularly in cancer. MiRNAs are involved in the modulation of fundamental pathways related to cancer, resembling cell cycle checkpoints and DNA repair pathways. MiRNAs are also rather stable and can reliably be detected in different types of biological materials, rendering them favorable diagnosis and prognosis biomarkers as well. MiRNAs have emerged as promising tools for evaluating medical outcomes in TC and as possible therapeutic targets. The contribution of miRNAs in thyroid cancer, particularly MTC, is an active area of research, and the utility of web applications and databases for the biological data analysis of miRNAs in TC is becoming increasingly important.

[Precision medicine in endocrinology exemplified by medullary thyroid cancer]

Medullary thyroid cancer (MTC) is a prime example for precision medicine in endocrinology and underlines the immediate benefits of basic, translational and healthcare research for patients with a rare disease in clinical . A mutation in the rearranged during transfection (RET) proto-oncogene that codes for a transmembrane receptor protein tyrosine kinase, leads to constitutive activation of the kinase, which is the decisive pathomechanism for the disease. The MTC occurs in a sporadic (somatic RET mutation) or hereditary form (RET germline mutation, multiple endocrine neoplasia types 2 and 3). For germline mutation carriers the timing of preventive thyroidectomy depends on the RET genotype. For advanced metastasized RET-mutant MTC, selective RET kinase inhibitors are available, which are currently considered to be game changers in the treatment. Based on the specific tumor marker calcitonin, MTC can be identified at an early stage during the differential diagnosis of thyroid nodules. The preoperative calcitonin level even enables statements on the degree of dissemination of the disease and on the probability of a cure through surgery. A new development is the consideration of desmoplasia as a histopathological biomarker for the metastatic potential of a MTC, which could possibly modify the operative approach as well as the future MTC nomenclature. Furthermore, the postoperative calcitonin level and the calcitonin doubling time are highly valid prognostic markers for tumor burden and biological aggressiveness of MTC and therefore decisive for patient follow-up. Biochemical, molecular and histological markers enable a risk-adapted surgical treatment and together with new targeted systemic treatments have contributed to a paradigm shift in the diagnostics, prognosis and treatment of MTC in recent years. Endocrine precision medicine for MTC therefore enabled a change from the previous purely symptom-oriented to a modern preventive and individualized treatment.

Tumor Grade and Molecular Characteristics Associated with Survival in Sporadic Medullary Thyroid Carcinoma

Background: The International Medullary Thyroid Carcinoma Grading System (IMTCGS) divides medullary thyroid carcinoma (MTC) into two categories, high- and low-grade tumors, which has a profound impact on patient outcomes. The aim of this study was to explore the association between IMTCGS grading, clinical data, and molecular status in sporadic MTC. Methods: A retrospective cohort study was performed on consecutive sporadic MTCs from patients undergoing initial surgery between January 2000 and January 2022 at the Padua Endocrine Surgery Unit. Clinical, pathological, and follow-up data were collected, tumors were graded, and somatic mutations of RET and RAS genes were analyzed. Patient outcomes were based on Ct levels and MTC-related deaths. Survival analyses were carried out employing the Kaplan-Meier method and the log-rank test. A Cox proportional hazard regression model was employed for multivariable survival analysis with the following covariates: somatic RET mutation, MTC stage at diagnosis, sex, age at diagnosis, and IMTCGS grade. Results: We included 141 consecutive sporadic MTCs. The median follow-up was 80.0 months (interquartile ranges: 41.5-122.5 months). Seventeen patients (12.1%) died from disease-related causes. 107/141 (76.9%) were classified as low-grade tumors, 32/141 (23.1%) as high-grade. Patients carrying a RET mutation had more aggressive features and shorter disease-specific survival (DSS) (p = 0.001) and were more frequently classified high-grade than low-grade MTC (p < 0.001). At multivariable survival analysis, only IMTCGS grading was independently associated with DSS (hazard ratio 8.8 [confidence interval: 2.7-28.3], p = 0.005). RET mutations, in particular RET-M918T, were more frequent in high-grade than in low-grade MTC (68.8% vs. 29.4% mutated in RET, 46.9% vs. 12.7% mutated in RET-M918T; p < 0.001). None of the high-grade tumors was mutated in the RAS gene, but the mutation was present in 11.8% of low-grade tumors. Conclusions: IMTCGS grading was associated with DSS independently of other clinical, pathological, and molecular factors. Moreover, MTC grading was associated with RET and RAS patterns, which explains, at least in part, the molecular basis of the aggressive behavior of high-grade MTC.

Simultaneous Occurrence of Medullary Thyroid Carcinoma and Papillary Thyroid Carcinoma: A Case Series with Literature Review

BACKGROUND

Papillary thyroid carcinoma (PTC) is the most common type of differentiated TC, while medullary TC (MTC) accounts for 4%. The concomitant presence of PTC and MTC is rare.

METHODS

This is a retrospective, single-center observational study conducted over 16 years (2001-2017). The data were collected from the clinical records of patients who underwent total thyroidectomy at the Endocrine Unit-Department of Medicine of the University Hospital of Pisa, Italy.

RESULTS

Over 690 analyzed cases, 650 (94.2%) were exclusive DTC, 19 exclusive MTC (2.75%) and 5 PTC/MTC (0.7%). No case of mixed medullary/follicular TC or hereditary MTC (familial MTC/multiple endocrine neoplasia type 2) was found. Among the five PTC/MTC cases, there was a male prevalence (M:F = 3:2), and all PTC components were at stage I, whereas 40% of MTC were at stage I and III and 20% of MTC were at stage II; microPTC (mPTC) was prevalent (80%) and also microMTCs were frequent (40%); 60% of MTC patients recovered, while 40% of patients developed metastatic disease. The search for germline mutations of the RET gene resulted in being negative in all cases.

CONCLUSIONS

The incidence of PTC/MTC has been increasing over the past 30 years. The etiology of PTC/MTC forms is still unknown, and although this simultaneous occurrence could be only a coincidence, we cannot exclude the hypothesis of a shared genetic origin.