Epidemiology and Clinical Presentation of Medullary Thyroid Carcinoma

An audit of medullary thyroid carcinoma from a tertiary care hospital in northwest India

Introduction

Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy originating from parafollicular C cells. It accounts for 5%-10% of all thyroid malignancies.

Methods

An ambispective analysis of pathologically proven MTC presented in a tertiary care hospital in northwest India was performed after considering demography, clinical manifestation, RET mutation status, management, and outcome as denominators.

Results

Among 2,735 thyroid malignancy cases who presented to our institute in the last 10 years (2012-2022), 78 (3%) had MTC with a mean age of presentation of 43 ± 11 years; 60% of them were female. The median duration of symptoms was 23 months (IQR 12-36 months). The most common presenting complaint was goiter with lymphadenopathy (80.8%). Among the atypical presentations, one each had ectopic Cushing's syndrome, hypertensive crisis in pregnancy due to pheochromocytoma, synchronous chondrosarcoma, and Von Hippel-Lindau disease spectrum. Median calcitonin and carcinoembryonic antigen (CEA) levels at presentation were 1,274 pg/mL (n = 64) and 149 ng/mL (n = 39), respectively. Twenty-two patients were germline RET mutation-positive, and they presented at a younger age. Majority of the patients presented with stage IV disease. Surgery was the primary modality of therapy. Twenty-nine patients received radiotherapy and 25 patients received tyrosine kinase inhibitors (TKIs). Nine patients received peptide receptor radiotherapy (PRRT) with Lu-177 with neoadjuvant capecitabine. Median progression-free survival (PFS) was 60 months. Patients without structurally and biochemically residual disease and stable disease after the first modality of therapy (Log-rank 11.4; p = 0.004) had a better PFS. Female patients (Log-rank: 9.5; p = 0.002) had a better PFS than male patients.

Conclusion

This study showed that MTC comprises 3% of thyroid malignancies with a female preponderance. RET mutation-positive patients had a younger age at presentation. Surgery was the first-line therapy. Radiotherapy, TKI, and PRRT were given as a part of second-line or third-line therapy due to persistent disease and/or disease recurrence. The median PFS was better in female patients and in patients who had no residual lesions and stable disease after the primary modality of therapy.

Germline founder variant c.1998delinsTTCT in the RET oncogene: a cohort study in 15 Belgian families

OBJECTIVE

The c.1998delinsTTCT variant in the RET gene (codon 666) is linked to medullary thyroid carcinoma in Belgium. We aimed to study the clinical phenotype and the age-dependent penetrance in predictive variant carriers.

DESIGN

Retrospective study of index patients and predictive variant carriers, identified through familial cascade testing between 2001 and 2020.

RESULTS

The total cohort comprised 119 patients: 15 index patients, 102 heterozygous, and 2 homozygous predictive variant carriers. Among heterozygous carriers, high suspicion of clinical disease was present in 25 patients at initial evaluation and in 3 patients during follow-up. No high suspicion of clinical disease was observed during surveillance in 56 patients, and 18 patients did not proceed to screening for clinical disease. Compared to index patients, surgically treated heterozygous predictive variant carriers had a lower presurgical basal calcitonin, a lower disease stage, less need for adjuvant therapy, and higher chances of remission. In heterozygous carriers, median age at developing high suspicion of disease is 52 years (range 7-75), with a predicted penetrance of 62% (9% SE) at the age of 70 years. Two patients were identified with pheochromocytoma and 1 patient with primary hyperparathyroidism. The 2 homozygous predictive variant carriers presented with higher disease severity at first clinical evaluation.

CONCLUSION

The c.1998delinsTTCT variant in the RET gene is pathogenic and associated with a moderate risk for medullary thyroid carcinoma and rarely with other multiple endocrine neoplasia type 2A (MEN2A) manifestations. Active surveillance is a possible option in heterozygous gene carriers with a negative first clinical evaluation.

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.

Early calcitonin levels in medullary thyroid carcinoma: Prognostic role in patients without distant metastases at diagnosis

Introduction

Calcitonin is the most specific marker for medullary thyroid carcinoma, thus, low detectable calcitonin values after surgery can conceal persistent disease. The present study aimed to explore the prognostic role of pre-operative and early calcitonin levels in patients without distant metastases at diagnosis.

Methods

A retrospective cohort of patients suffering from medullary thyroid carcinoma was considered (N=55). The final disease status, i.e. complete response (undetectable calcitonin levels and negative radiological assessments) or persistent disease (detectable calcitonin levels and/or positive radiological assessments), was deduced from the last available follow-up. Pre-operative and early calcitonin levels (i.e. six months after surgery) have been correlated to several clinical and histological features, according to the final disease status.

Results

Persistent disease patients showed higher pre-operative and early calcitonin values (p=0.028 and p<0.001, respectively), compared to complete response sub-cohort. Cox-regression models show that early detectable calcitonin increases up to 18-fold the risk of persistent disease, independently from tumour size and pre-operative calcitonin levels (p=0.006). Of note, when considering only patients who finally developed distant metastasis, ROC curve analysis shows that an early calcitonin level ≥16 pg/ml predicts the final disease status with a sensitivity of 89% and a specificity of 82% (AUC=0.911, CI95%: 0.819-1000, p<0.001).

Conclusion

Calcitonin levels six months after surgery represents an easy and effective predictor of persistent disease for medullary thyroid carcinoma without distant metastasis at diagnosis.

Preventive Transoral Endoscopic Thyroidectomy by Vestibular Approach in 6-Year-Old Patient with the High-Risk RET C634R Germline Mutation

Aggressiveness and age of manifestation of medullary thyroid cancer depend on the risk level of germline RET mutations. For high-risk mutations, preventive thyroidectomy is recommended at young age. In recent years, endoscopic operations for thyroid cancer were introduced in clinical practice. But such experience in pediatrics is very limited. We present a case report of a male patient, 6-year-old with the high-risk germline mutation С634R in RET gene. Close relatives (mother, cousin, and native sister) of the proband, were treated for medullary thyroid cancer. Also, his grandmother on the maternal line and her native brother died at the age of 38 and 37 years because of medullary thyroid cancer progression. Since 3 years old, our patient was under regular exams. At the age of six, calcitonin level was 8 ng/mL, and no evidence of pathology on ultrasound. According to recommendations of American Thyroid Association from 2015 (ATA 2015), preventive thyroidectomy was planned. This operation was performed by transoral vestibular approach. Oral nutrition started on the first day after the operation and the patient was discharged from the hospital. No major complications were observed. Transitory paresthesia and slight edema of the submental compartment were noticed. Consider this, endoscopic operation on the thyroid gland can be performed, as a preventive procedure, for RET gene germline mutation carriers in young age. This method helps avoid scars on the skin of the anterior neck.

Performing Calcitonin Immunocytochemistry on an Additional ThinPrep Slide in Fine-Needle Aspiration Diagnosis of Medullary Thyroid Carcinoma

OBJECTIVES

This study reviewed the institutional experience of performing calcitonin immunostain on an additional ThinPrep slide in fine-needle aspiration (FNA) diagnosis of medullary thyroid carcinoma (MTC).

METHODS

Thyroid FNA cases with MTC suspected or included in the differential diagnosis during cytologic evaluation and calcitonin immunostain performed were retrieved and reviewed.

RESULTS

Calcitonin immunostain was performed in 132 cases with 41 positive, 81 negative, and 10 indeterminate results. All calcitonin-positive cases had a cytologic diagnosis of MTC while all calcitonin-negative cases were cytologically classified as non-MTCs except for two cases suspicious for MTC. In 10 cases with an indeterminate calcitonin result, diagnoses of non-MTC and suspicious for MTC were rendered in 6 and 4 cases, respectively. Histopathologic follow-up was available in 85 (64%) cases. All cytologically diagnosed MTC cases were confirmed on histopathology. In 3 MTC cases with an indeterminate calcitonin result, 1 case was misclassified cytologically as follicular neoplasm. The calculated sensitivity, specificity, positive predictive value, and negative predictive value of calcitonin immunostain were all 100% for diagnosing MTC.

CONCLUSIONS

Our study demonstrates the feasibility of performing calcitonin immunostain on an additional ThinPrep slide. Calcitonin immunocytochemistry is a valuable adjunct test for FNA diagnosis and differential diagnosis of MTC.

Surgical aspects and controversies in the management of medullary thyroid cancer

Medullary thyroid cancer (MTC) accounts for only 4% of thyroid carcinomas but 15% of thyroid cancer deaths. MTC is a tumour of the calcitonin secreting parafollicular C cells in the thyroid which can occur sporadically or be hereditary in multiple endocrine neoplasias type 2 syndromes due to germline RET mutations. Sporadic forms of MTC can also be caused by mutations in the RET protooncogene. MTC commonly presents in a late stage, with 70% of patients presenting with local nodal metastasis. Currently, the only curative treatment for MTC is surgical removal. The aim of this paper is to describe the current guidelines and progressions of the surgical management of MTC and to highlight up-and-coming chemotherapies. A database literature review was completed utilizing PubMed to cumulate the extant literature, screening for most recent guidelines and publications regarding the management of MTC. Current guidelines were described by the American Thyroid Association in 2015. Controversial publications continue to present supporting evidence for varying degrees of thyroidectomy and neck dissections. Recently, researchers have been exploring non-surgical options including external beam radiotherapy and multikinase inhibitors such as vandetanib and cabozantinib for the treatment of MTC. Surgical management of MTC remains controversial and varies significantly dependent on the extent of disease. Chemotherapeutic options have undetermined effects on survival to date.

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

Background

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

Methodology

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

Results

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

Conclusion

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

Anesthesia and Outcome of 33 Surgeries in 24 Multiple Endocrine Neoplasia Type 2A (MEN2A) Patients: A National Rare Disease Center's Experience

BACKGROUND

Multiple endocrine neoplasia type 2A (MEN2A) is a rare syndrome that presents as medullary thyroid carcinoma, pheochromocytoma, and hyperparathyroidism. Experience is lacking in the anesthetic management of patients with this syndrome, particularly in those who present with pheochromocytoma receiving nonpheochromocytoma resection. We aimed to share our experience with the anesthetic management of MEN2A patients.

METHOD

We retrospectively enrolled 24 MEN2A patients who had received different types of surgery at Peking Union Medical College Hospital from January 1, 2015, to December 31, 2021. All the medical records were reviewed and analyzed.

RESULT

In total, 33 surgeries were performed in 24 MEN2A patients, with 20 surgeries comprising pheochromocytoma resection in 17 patients. Most of these patients who had received pheochromocytoma resection had typical hemodynamic changes during surgery and anesthesia. Regarding the other 13 nonpheochromocytoma resections in 13 patients, 10 were performed in patients without pheochromocytoma, and 3 surgeries were performed with either functional primary (1, bilateral tumor whose patient refused adrenalectomy) or metastatic pheochromocytoma (2, unresectable and malign tumors developed years after bilateral adrenalectomy). Regarding the latter 3 patients, 1 showed hypertension and tachycardia during anesthesia induction, 1 showed tachycardia during surgery and the other showed stability during surgery. Patients who had received pheochromocytoma resection (n=17) required longer postoperative hospital stays than those who had received nonpheochromocytoma resection without pheochromocytoma (n=10) (5.8 ± 1.8 vs. 4.3 ± 1.6; P = 0.031).

CONCLUSIONS

Whenever MEN2A patients are diagnosed with pheochromocytoma, surgical resection of the pheochromocytoma remains the primary choice for MEN2A treatment. Nonpheochromocytoma surgeries performed with existing pheochromocytoma could be risky and require full caution and preparation.

Calcitonin and complementary biomarkers in the diagnosis of hereditary medullary thyroid carcinoma in children and adolescents

OBJECTIVES

Medullary thyroid carcinoma (MTC) is a rare malignancy that is effectively curable by surgery. Unlike in adults, hereditary MTC has a predominant role in children. A fast and safe diagnosis is important to assure the good prognosis for the patients. A major cornerstone is the assessment of biomarkers, but the interpretation must respect their pre-, post- and analytical features. Especially calcitonin (Ctn) is a challenging biomarker in daily laboratory diagnostics. However, Ctn is of particular relevance for the diagnostic in MTC. The American Thyroid Association recommends thyroidectomy if the upper reference range of Ctn is exceeded. Interestingly, age-dependent reference ranges for children and adolescents have become available only recently for Ctn assays. With this review, we aim to highlight the importance of a timely diagnosis of MTC in children and adolescents.

CONTENT

Recent developments in pediatric biochemical diagnostics of MTC were summarized. This includes guidance on interpretation of RET, Ctn, procalcitonin, carcinoembryonic antigen, carbohydrate antigen 19-9, and chromogranin A.

SUMMARY

Currently, Ctn is the most investigated biomarker in the diagnosis of MTC in children and adolescents. Other biomarkers as PCT suggest complementary evidence about pediatric MTC but their interpretation based largely on adult's data. A successful treatment of MTC requires, besides results of biomarkers, information about medical history, RET gene analysis and recent guideline knowledge.

OUTLOOK

More research is required to validate complementary biomarkers of Ctn in children. Additionally, the effect of different confounder on pediatric Ctn levels has to be further clarified.

Spindle cell variant of medullary thyroid carcinoma: a clinicopathologic study of four cases

Background

Medullary thyroid carcinoma (MTC) is a malignant tumor derived from C cells. It accounts for about 10% of all thyroid malignancies. More than 14 histological variants have been described. Among them, spindle cell variant is extremely rare.

Case presentation

Here we describe 4 cases of spindle cell variant of MTC collected from 2012 to 2019. Ultrasound showed solid and hypoechoic nodules. Three patients underwent total thyroidectomy and regional lymph node dissection, and 1 patient underwent thyroid mass resection. Histologically, the tumors showed spindle shaped cells in bundles or interlaced arrangement, separated by hyalinised fibrous stroma that contained amyloid deposits. Immunohistochemistry showed that the tumor cells were positive for calcitonin, chromogranin A, synaptophysin, CD56, and TTF-1, but negative for other lineage-specific markers.

Conclusions

We report 4 rare cases of spindle cell variant of MTC. Due to its rarity and special morphology, the diagnosis of spindle cell variant MTC relies on its morphology and immunohistochemical markers to avoid misdiagnosis.

Osteopontin Expression in Thyroid Cancer: Deciphering EMT-Related Molecular Mechanisms

Thyroid cancer is the most common tumor arising from the endocrine system and generally presents good prognosis. However, its aggressive subtypes are related to therapeutic resistance and early metastasis. Epithelial–mesenchymal transition (EMT) and its reverse process, the mesenchymal–epithelial transition (MET), are key events mediating cancer progression, including in thyroid cancer. The matricellular protein osteopontin (OPN) has been reported as a master regulator of EMT in many tumor types. Although high OPN expression has been described and associated with important aspects of thyroid cancer progression, there is no clear evidence regarding OPN as a regulator of EMT in thyroid cancer. Thus, taking together the known roles of OPN in the modulation of EMT in cancer and the information reporting the expression of OPN in thyroid tumor progression, this review aims at summarizing and discussing data related to EMT in thyroid cancer and its putative relation to the roles of OPN in the development of thyroid cancer. These data provide new insights into the molecular mechanisms by which OPN could potentially modulate EMT in thyroid tumors, generating evidence for future studies that may contribute to new therapeutic, prognostic and/or diagnostic tools.

Significance of chromogranin A and synaptophysin in medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare thyroid carcinoma of C-cell deviation that produces and secretes calcitonin (CT) and chromogranin A (CgA) into the blood. Thus, CT and CgA are immunohistochemical and serum markers for MTCs. MTC occurs in sporadic and inheritable forms. The hallmark of inheritable cases in multiple endocrine neoplasm 2 (MEN2) is MTC. MEN2 cases represent 30% through germline RET proto-oncogene mutation and occur in younger ages involving bilateral thyroid lobes. Sporadic cases are 70% and occur in older ages. CgA and synaptophysin (SPY) are the two most widely used and reliable immunohistochemical markers for neuroendocrine tumors, including MTCs. This study aimed to detect different immunohistochemical staining patterns for CgA and SPY between non-symptomatic small lesions and invading larger aggressive tumors in both MEA2 cases and sporadic cases. There was different CgA and SPY immunostaining in MEA2 cases where small tumors (≤0.3 cm) were lesser immunostained for CgA and SPY, despite intense staining for CT, compared to the larger (≥0.5 cm) tumors, stronger immunostained for CgA. There was also different CgA and SPY immunohistochemical staining in sporadic cases between small lesions (≤0.5 cm) and larger tumors (≥1.0 cm). One small sporadic tumor (0.5 cm × 0.3 cm) was strongly and weakly, patchy stained for CgA and SPY, respectively, while larger sporadic tumors were diffusely and strongly stained for CgA and SPY. Therefore, stronger CgA and SPY immunostaining for larger tumors in both MEA2 and sporadic cases may be used as independent, aggressive immunohistochemical markers for MTCs.

Sonographic risk factors of aggressive behaviors in medullary thyroid carcinomas

OBJECTIVE

To identify the clinical and sonographic risk factors for aggressive behavior of Medullary Thyroid Carcinomas (MTCs).

MATERIAL AND METHODS

This is a retrospective analysis. The informed consents were waived. Totally, 127 patients were selected from the database. Two radiologists were invited to review the clinical records and ultrasonic images and scored all the cases according to ACR TI-RADS, retrospectively. Kappa test was used to evaluate the consistency between the two reviewers. Logistic regression analysis was carried to identify the risk factors for aggressive behaviors of MTCs. Comparison of survival proportions between different groups were calculated by Kaplan-Meier method and log-rank test.

RESULTS

Female patients with MTCs were more commonly seen than male (1.7:1), male sex was a risk factor for both metastasis (OR: 4.471, P = 0.001) and perithyroidal invasion (OR = 4.674, P = 0.004). Consistency between the two reviewers were quite high (K value, 0.797-0.988). On sonograms, typical MTCs manifest as hypoechoic (96.9%) solid nodules (94.5%). Sex of patients (P = 0.001), margin (P = 0.003) and focality (P = 0.01) of the nodule were independent risk factors for metastasis, whereas sex of the patients (P = 0.004) and margin (P = 0.000) were independent risk factors for perithyroidal invasion. By Kaplan-Meier analysis, survival proportions different between groups with/without perithyroidal extension (P = 0.000) but not between groups with/without metastasis (P = 0.473).

CONCLUSION

High frequency ultrasound and TI-RADS were effective methods for preoperative diagnosis of MTC. Sex of the patients and margin of the nodule are common risk factors for both metastasis and perithyroidal invasion. Focality of the tumor is another independent risk factor for metastasis.

Essential Role of the 14q32 Encoded miRNAs in Endocrine Tumors

BACKGROUND

The 14q32 cluster is among the largest polycistronic miRNA clusters. miRNAs encoded here have been implicated in tumorigenesis of multiple organs including endocrine glands.

METHODS

Critical review of miRNA studies performed in endocrine tumors have been performed. The potential relevance of 14q32 miRNAs through investigating their targets, and integrating the knowledge provided by literature data and bioinformatics predictions have been indicated.

RESULTS

Pituitary adenoma, papillary thyroid cancer and a particular subset of pheochromocytoma and adrenocortical cancer are characterized by the downregulation of miRNAs encoded by the 14q32 cluster. Pancreas neuroendocrine tumors, most of the adrenocortical cancer and medullary thyroid cancer are particularly distinct, as 14q32 miRNAs were overexpressed. In pheochromocytoma and growth-hormone producing pituitary adenoma, however, both increased and decreased expression of 14q32 miRNAs cluster members were observed. In the background of this phenomenon methodological, technical and biological factors are hypothesized and discussed. The functions of 14q32 miRNAs were also revealed by bioinformatics and literature data mining.

CONCLUSIONS

14q32 miRNAs have a significant role in the tumorigenesis of endocrine organs. Regarding their stable expression in the circulation of healthy individuals, further investigation of 14q32 miRNAs could provide a potential for use as biomarkers (diagnostic or prognostic) in endocrine neoplasms.

DNA repair pathway activation features in follicular and papillary thyroid tumors, interrogated using 95 experimental RNA sequencing profiles

DNA repair can prevent mutations and cancer development, but it can also restore damaged tumor cells after chemo and radiation therapy. We performed RNA sequencing on 95 human pathological thyroid biosamples including 17 follicular adenomas, 23 follicular cancers, 3 medullar cancers, 51 papillary cancers and 1 poorly differentiated cancer. The gene expression profiles are annotated here with the clinical and histological diagnoses and, for papillary cancers, with BRAF gene V600E mutation status. DNA repair molecular pathway analysis showed strongly upregulated pathway activation levels for most of the differential pathways in the papillary cancer and moderately upregulated pattern in the follicular cancer, when compared to the follicular adenomas. This was observed for the BRCA1, ATM, p53, excision repair, and mismatch repair pathways. This finding was validated using independent thyroid tumor expression dataset PRJEB11591. We also analyzed gene expression patterns linked with the radioiodine resistant thyroid tumors (n = 13) and identified 871 differential genes that according to Gene Ontology analysis formed two functional groups: (i) response to topologically incorrect protein and (ii) aldo-keto reductase (NADP) activity. We also found RNA sequencing reads for two hybrid transcripts: one in-frame fusion for well-known NCOA4-RET translocation, and another frameshift fusion of ALK oncogene with a new partner ARHGAP12. The latter could probably support increased expression of truncated ALK downstream from 4th exon out of 28. Both fusions were found in papillary thyroid cancers of follicular histologic subtype with node metastases, one of them (NCOA4-RET) for the radioactive iodine resistant tumor. The differences in DNA repair activation patterns may help to improve therapy of different thyroid cancer types under investigation and the data communicated may serve for finding additional markers of radioiodine resistance.

Do medullary thyroid carcinoma patients with high calcitonin require bilateral neck lymph node clearance? A case report

BACKGROUND

In clinical work, 85%-90% of malignant thyroid diseases are papillary thyroid cancer (PTC); thus, clinicians neglect other types of thyroid cancer, such as medullary thyroid carcinoma (MTC).

CASE SUMMARY

We report a 53-year-old female patient with a preoperative calcitonin level of 345 pg/mL. There was no definitive diagnosis of MTC by preoperative fine-needle aspiration cytology or intraoperative frozen pathology, but the presence of PTC and MTC was confirmed by postoperative paraffin pathology. The patient underwent total thyroidectomy and bilateral central lymph node dissection. Close follow-up at 1.5 years after surgery revealed no signs of recurrence or metastasis.

CONCLUSION

The issue in clinical work-up regarding types of thyroid cancer provides a novel and challenging idea for the surgical treatment of MTC. In the absence of central lymph node metastasis, it is worth addressing whether patients with high calcitonin can undergo total thyroidectomy and bilateral central lymph node dissection without bilateral lateral neck lymph node dissection.

FDA Approval Summary: Selpercatinib for the Treatment of Lung and Thyroid Cancers with RET Gene Mutations or Fusions

On May 8, 2020, the FDA granted accelerated approval to selpercatinib for (i) adult patients with metastatic RET fusion-positive non-small cell lung cancer (NSCLC), (ii) adult and pediatric patients ≥12 years of age with advanced or metastatic RET-mutant medullary thyroid cancer who require systemic therapy, and (iii) adult and pediatric patients ≥12 years of age with advanced or metastatic RET fusion-positive thyroid cancer who require systemic therapy and who are radioactive iodine refractory (if radioactive iodine is appropriate). Approval was granted on the basis of the clinically important effects on the overall response rate (ORR) with prolonged duration of responses observed in a multicenter, open-label, multicohort clinical trial (LIBRETTO-001, NCT03157128) in patients whose tumors had RET alterations. ORRs within the approved patient populations ranged from 64% [95% confidence interval (CI), 54-73] in prior platinum-treated RET fusion-positive NSCLC to 100% (95% CI, 63-100) in systemic therapy-naïve RET fusion-positive thyroid cancer, with the majority of responders across indications demonstrating responses of at least 6 months. The product label includes warnings and precautions for hepatotoxicity, hypertension, QT interval prolongation, hemorrhagic events, hypersensitivity, risk of impaired wound healing, and embryo-fetal toxicity. This is the first approval of a drug specifically for patients with RET alterations globally.

Structural Doubling Time Predicts Overall Survival in Patients with Medullary Thyroid Cancer in Patients with Rapidly Progressive Metastatic Medullary Thyroid Cancer Treated with Molecular Targeted Therapies

Purpose: To evaluate the impact of structural disease progression of metastatic lesions after initial surgery on overall survival (OS) of patients presenting with metastatic medullary thyroid cancer (MTC). We used tumor volume doubling time (TVDT) as a marker of structural disease progression and aimed to correlate the average structural tumor volume doubling time (midDT) with OS in MTC patients after initial surgery. Methods: In this retrospective study, we examined the clinical characteristics; average tumor volume doubling times of neck, lung, and liver metastasis; and disease-specific survival of patients with metastatic MTC. Results: Tumor growth is constant in MTC metastasis, irrespective of location of the metastasis. The median correlation coefficient (r) and the coefficient of determination (r²) were similar in lung metastasis (r = 0.91, r² = 0.95) and liver metastasis (r = 0.88, r² = 0.94), and comparable in neck metastasis (r = 0.73, r² = 0.85). Patients with metastatic MTC with a midDT ≤1 year have a worse prognosis than those with higher midDT (p = 0.002). Those with midDT ≤1 year had a median OS of 11.1 years [confidence interval (CI) 7.4-14.8 years]. In contrast, patients with midDT 1-3 years had a median OS of 16.5 years [CI 10.3-22.6 years]. All patients with midDT ≥3 survived by the end of the follow-up period. Preliminary results suggest that measurement of midDT can predict response to molecular targeted therapies. Conclusions: In conclusion, TVDT is a strong predictor of OS in patients with recurrent or metastatic MTC, can be used as a marker of progression, and potentially can help select patients who may benefit from molecular targeted therapy.

Medullary Thyroid Carcinoma Presenting as Metastatic Disease to the Breast

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

Calcitonin measurement in pediatrics: reference ranges are gender-dependent, validation in medullary thyroid cancer and thyroid diseases

BACKGROUND

There is only limited information on serum reference ranges of calcitonin (CT) in infants, children and adolescents. This gap hampers valid diagnostics in patients with multiple endocrine neoplasia type 2 (MEN 2) and planned prophylactic thyroidectomy. In addition, age-dependent reference ranges for CT are necessary to define a cure in medullary thyroid carcinoma (MTC). We asked whether the reference ranges for CT levels were age- and gender-dependent in the serum of a pediatric cohort.

METHODS

A total of 6090 serum samples of 2639 subjects of the LIFE-Child cohort aged between 1 month and 17.9 years were analyzed by the CT electrochemiluminescence immunoassay (ECLIA). Reference intervals were estimated using the LMS method. For clinical validation the serum of 28 patients (61 samples) with MEN 2 and 106 patients (136 samples) with thyroid diseases were analyzed.

RESULTS

CT levels showed a clear age- and gender-dependence with significantly higher values in boys (p<0.01). An accelerated decline of CT levels from newborn to children at the age of 4 and 5 years was observed for both sexes. A cure for MTC was demonstrated in 71% of MEN 2 patients after thyroidectomy, whereas 5 patients remained suspicious for micrometastasis or relapse. Only 1.5% of our patients with thyroid diseases revealed increased CT levels.

CONCLUSIONS

This is the largest study to establish novel pediatric reference ranges from the CT values of healthy subjects. It allows a precise laboratory monitoring of CT in pediatric patients with MEN 2. Thyroid diseases did not have a relevant influence on CT levels in our pediatric cohort.

Medullary thyroid cancer: epidemiological pattern and factors contributing to recurrence and metastasis

INTRODUCTION

Medullary thyroid carcinoma (MTC) is a neuroendocrine thyroid carcinoma with parafollicular C cell differentiation. It can occur in either sporadic or hereditary form. Surgery is still the only curative treatment. The efficacy of chemotherapy and radiotherapy is poor.

METHODS

This was a retrospective study of 31 patients treated surgically for MTC in our oncology centre at Mansoura University between January 2008 and February 2019.

RESULTS

The mean age at diagnosis was 39.9 years. The median pathological size was 4cm. Multifocal disease was found in 12 patients and extrathyroid extension in 3 cases. Twenty patients were pathologically node positive. The median number of positive lymph nodes was four. Seven cases were metastatic at diagnosis. Local recurrence occurred in six individuals while distant recurrence occurred only in one. The median time from surgery to local recurrence was 12 months. The estimated mean disease free survival was 56.5 months. Disease free survival was significantly related to age, metastasis and side of nodal spread.

CONCLUSIONS

In our study cohort, the disease occurred predominantly in women and younger patients. Age, distant metastasis and nodal spread were the most significant prognostic factors. This study has also demonstrated that prognosis is not only affected by nodal involvement but also by side of involvement. The role of hemithyroidectomy in node negative unifocal disease with a small tumour size warrants further investigation.

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

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

Novel Prognostic Factors Associated with Cell Cycle Control in Sporadic Medullary Thyroid Cancer Patients

BACKGROUND

Medullary thyroid cancer (MTC) is a rare neuroendocrine-derived malignancy. It is represented by sporadic and familiar forms, and both can have RET oncogene mutations. Numerous markers can be used to define MTC; however, none is generally approved for predicting the outcome of sporadic MTC.

AIM

The aim of this work was to analyze PTTG1/securin and Aurora kinase A expressions in MTC patients, both at the gene and protein levels, and to define their prognostic role in MTC assessing their association with lab and clinical parameters.

PATIENTS AND METHODS

Seventy-one sporadic MTC human samples were analyzed for RET mutations and by qPCR for PTTG1 and AURKA (Aurora kinase A) expression. Ki-67 levels and western blot reactivity for PTTG1 and Aurora kinase A were also determined in a selected cohort of patients.

RESULTS

RET somatic mutations were found in 48% of the patients (34/71). PTTG1 expression was statistically different among the groups with or without regional lymph node metastasis (p < 0.0001) and advanced stage disease (p < 0.01). PTTG1 and AURKA expressions were statistically higher than those of controls (p = 0.01 and p < 0.002, respectively). PTTG1 expression and Ki-67 levels were statistically different among the groups with remitted or persistent disease (p < 0.05 and p < 0.01, respectively). We found a significant correlation between the expressions of AURKA and PTTG1 (p < 0.0002, r = 0.5298) and between the expressions of PTTG1 and Ki-67 (p = 0.01). Ki-67 levels were statistically different among the groups with or without metastatic lymph nodes (p = 0.01) or distant metastases (p = 0.003).

CONCLUSION

The presence of an altered expression of PTTG1 and AURKA is a negative prognostic factor associated with a more aggressive course of disease, such as an advanced stage or disease persistence. It emerges as a cell cycle process mediated by the 2 factors, in addition to the RET pathway, which can be altered in MTC patients.

Recent Development of Nuclear Molecular Imaging in Thyroid Cancer

Therapies targeting specific tumor pathways are easy to enter the clinic. To monitor molecular changes, cellular processes, and tumor microenvironment, molecular imaging is becoming the key technology for personalized medicine because of its high efficacy and low side effects. Thyroid cancer is the most common endocrine malignancy, and its theranostic radioiodine has been widely used to diagnose or treat differentiated thyroid cancer. This article summarizes recent development of molecular imaging in thyroid cancer, which may accelerate the development of personalized thyroid cancer therapy.

Thyroid Cancer: Risk-Stratified Management and Individualized Therapy

Thyroid cancer is the most common endocrine malignancy. Differentiated thyroid cancer (DTC) with the two subtypes, papillary thyroid cancer (PTC) and follicular thyroid cancer (FTC), is the most frequent subtype of thyroid cancer; more rare subtypes are medullary thyroid cancer (MTC) and anaplastic thyroid cancer (ATC). The incidence of DTC has increased rapidly in recent years due to the more frequent use of imaging methods such as ultrasound of the neck and fine-needle aspiration (FNA) of thyroid nodules. After total thyroidectomy and radioiodine treatment, DTC remains an indolent and curable disease in most patients, whereas the cure rate in MTC is lower and depends on early diagnosis. Most ATCs are incurable. In recent years, there has been great progress in identifying genetic changes in thyroid cancer, and genetic testing of FNA samples or blood samples provides useful information for clinical decision making. Tumor staging, either postoperatively or by imaging, and measuring the tumor markers thyroglobulin for DTC and calcitonin for MTC, allow for dynamic risk-adapted stratification for follow-up procedures. In advanced metastatic thyroid cancer, molecular targeted therapy using tyrosine kinase receptor inhibitors, including sorafenib, lenvantinib, vandetanib, and cabozantinib, helps control tumor progression and prolongs progression-free survival. Using a dynamic risk-stratified approach to manage thyroid cancer, the outcomes for most thyroid cancer patients are excellent compared with those for other cancers. The major challenge in the future is to identify high-risk patients and to treat and monitor them appropriately. Clin Cancer Res; 22(20); 5012-21. ©2016 AACR SEE ALL ARTICLES IN THIS CCR FOCUS SECTION, "ENDOCRINE CANCERS REVISING PARADIGMS".

RET mutation heterogeneity in primary advanced medullary thyroid cancers and their metastases

Purpose

Medullary Thyroid Cancer (MTC) whose pathogenesis is strictly related to RET proto-oncogene alterations, has been shown to have a heterogenic RET mutation profile in subpopulations of MTC. The aim of our study was to investigate the RET somatic mutation profile in primary MTC and in the corresponding metastatic tissues in a series of advanced metastatic cases.

Results

This study demonstrated that in about 20% of cases a different RET mutation profile can be found when comparing primary tumor and its corresponding metastases. Furthermore in 8% of tumors, RET intratumor heterogeneity was observed We also showed that in some cases an imbalance of RET copy number was present. We confirmed a high prevalence (90%) of RET somatic mutations in advanced tumors.

Materials and Methods

Fifty-six MTC patients (50 somatic and 6 hereditary cases) have been included in the study and a total of 209 specimens have been analysed by direct sequencing. Multiplex ligation-dependent probe amplification (MLPA) has been used to investigate amplification/deletion of RET alleles.

Conclusions

In conclusion, this study showed a genetic intra- and intertumor heterogeneity in MTC, But in only 20% of CASES These results could justify the relatively moderate level of aggressiveness of the disease with respect to more aggressive human tumors that are characterized by a high rate of mutation and heterogeneity.