Early, Prophylactic Thyroidectomy in Hereditary Medullary Thyroid Carcinoma: A 26-year Monoinstitutional Experience

Serum Biochemical Markers for Medullary Thyroid Carcinoma: An Update

INTRODUCTION

Medullary thyroid carcinoma (MTC), a rare malignancy, requires early diagnosis for optimal patient outcomes. An important aspect of MTC diagnosis is the assessment of serum biomarkers. This review aimed to evaluate the use of serum biomarkers in the diagnosis, prognosis, and follow-up of MTC.

METHODS

A thorough search of PubMed covering 1975 to 2022 was conducted to identify English-language articles on MTC serum biomarkers.

RESULTS

The review revealed that calcitonin (Ctn) and carcinoembryonic antigen (CEA) remain the most important serum biomarkers for MTC diagnosis and management. Despite limited studies on procalcitonin (PCT), its stability and ability to exclude interference from inflammation make it a valuable potential marker of MTC. Although the positive rate of serum CA19-9 levels in MTC patients was not high, it can be used as an indicator of poor prognosis in advanced MTC. Other serum markers, including chromogranin A, gastrin-releasing peptide precursor, and neurospecific enolase, did not show any unique value in MTC diagnosis and management.

CONCLUSION

Taken together, this review emphasized the importance of serum biomarkers, particularly Ctn and CEA, in the diagnosis and management of MTC. PCT shows promise as a valuable potential marker, whereas CA19-9 can be used as a prognostic indicator of advanced MTC. Further research is needed to validate the significance of these serum biomarkers in MTC and determine the effects of confounding factors on their levels. Clinicians should consider using these markers in MTC diagnosis, prognosis, and follow-up, particularly for patients with advanced disease.

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.

Prophylactic and Early Thyroidectomy in RET Germline Mutation Carriers in Pediatric and Adult Population: Long-Term Outcomes of a Series of 63 Patients

Prophylactic and early thyroidectomy in RET germline mutation carriers allows the removal of the thyroid before medullary thyroid carcinoma (MTC) develops, or while it is still confined to the gland. This study was aimed to assess the clinicopathological features in RET carriers according to the age at surgery and the long-term outcomes after prophylactic and early thyroidectomy. A retrospective analysis of 63 operated asymptomatic RET carriers diagnosed after familial genetic screening was performed. Twenty-one RET carriers were operated at pediatric (<18 yrs) and 42 at adult (≥18 yrs) age. Serum preoperative calcitonin levels were significantly lower in pediatric compared to adult patients (p = 0.04); moreover, adult RET carriers had a greater frequency of microMTC at pathology (p = 0.009). Permanent postoperative morbidity occurred in 9.5% of patients, without differences between the two groups. Biochemical postoperative cure was achieved in all patients. At a median follow-up of 14 years, all C-cell hyperplasia patients are disease-free; conversely, biochemical, and structural recurrence of disease occurred in three adults and one pediatric patient with microMTC. The independent predictive factors of MTC were the age at surgery, the preoperative calcitonin level and the RET mutational risk profile (p < 0.02). In conclusion, prophylactic and early thyroidectomy are safe and effective procedures in achieving definitive cure in most RET carriers. However, since recurrences may occur at long-term in case of microMTC, thyroidectomy should be possibly performed earlier to prevent microMTC development.

5P Strategies for Management of Multiple Endocrine Neoplasia Type 2: A Paradigm of Precision Medicine

Multiple endocrine neoplasia type 2 (MEN2) is a neuroendocrine cancer syndrome characterized by medullary thyroid carcinoma, in combination or not with pheochromocytoma, hyperparathyroidism, and extra-endocrine features. MEN2 syndrome includes two clinically distinct forms subtyped as MEN2A and MEN2B. Nearly all MEN2 cases are caused by germline mutations of the RET proto-oncogene. In this review, we propose "5P" strategies for management of MEN2: prevention, prediction, personalization, psychological support, and participation, which could effectively improve clinical outcomes of patients. Based on RET mutations, MEN2 could be prevented through prenatal diagnosis or preimplantation genetic testing. Identification of pathogenic mutations in RET can enable early diagnosis of MEN2. Combining RET mutation testing with measurement of serum calcitonin, plasma or urinary metanephrine/normetanephrine, and serum parathyroid hormone levels could allow risk stratification and accurately prediction of MEN2 progression, thus facilitating implementation of personalized precision treatments to increase disease-free survival and overall survival. Furthermore, increased awareness of MEN2 is needed, which requires participation of physicians, patients, family members, and related organizations. Psychological support is also important for patients with MEN2 to promote comprehensive management of MEN2 symptoms. The "5P" strategies for management of MEN2 represent a typical clinical example of precision medicine. These strategies could effectively improve the health of MEN2 patient, and avoid adverse outcomes, including death and major morbidity, from MEN2.

RET S409Y Germline Mutation and Associated Medullary Thyroid Carcinoma

Background: Inherited medullary thyroid carcinoma (MTC) is primarily caused by RET mutations that are commonly localized in exons 5, 8, 10, 11, and 13-16. In this study, we report pedigrees for individuals with MTC that harbor a germline S409Y variant within exon 6 of the RET proto-oncogene. Methods: Targeted sequencing was used to diagnose four apparently sporadic MTC index cases carrying the germline RET S409Y (c.1226 C>A) variant. Subsequently, 27 relatives of these individuals underwent clinical and genetic assessments and/or thyroid surgery. Furthermore, in silico analyses and in vitro assays were performed to predict or verify the potential oncogenic activity of the S409Y variant. Results: Overall, 15 of 31 participants were found to carry the RET S409Y variant. Of these, 6 presented with isolated MTC (mean age 50.2 years; range 41-75 years), of which 3 presented with neck lymph node metastases and 2 presented with distant liver or lung metastases. Among the remaining 9 carriers, 3 (mean age 56 years; range 41-76 years) had elevated serum calcium-stimulated calcitonin (sCtn) or concurrent marginally elevated serum calcitonin (Ctn) levels, whereas the other 6 (mean age 37.5 years; range 14-52 years) exhibited typical Ctn/sCtn levels (p < 0.05). None of the 15 carriers in these 4 families presented clinical evidence of pheochromocytoma, hyperparathyroidism, or Hirschsprung's disease. In silico analyses revealed that S409Y was a "possibly damaging" mutation that could affect the RET protein inter-domain interface. An in vitro assay revealed that the phosphorylation level of RET tyrosine 905 was relatively higher in the RET S409Y mutant than in wild-type (WT) RET. Moreover, transfection of HEK 293 cells with S409Y enhanced the phosphorylation activity of AKT, ERK pathways, and it increased cell proliferation compared with WT RET, but to a lesser degree than that for the RET C618Y and C634Y mutations. Conclusions: This study demonstrates that the novel germline RET S409Y variant is likely pathogenic and is associated with lower penetrance of MTC than that for the C618Y and C634Y mutations. Individuals with S409Y should be managed using a personalized approach, and additionally, "at-risk" family members should be evaluated. Additional studies are needed to elucidate the correlation between the S409Y mutation and multiple endocrine neoplasia type 2-specific tumors.

Prophylactic thyroidectomy in multiple endocrine neoplasia type 2A in children: a single centre experience

Background To describe the complications and long-term results in patients with multiple endocrine neoplasia type 2A (MEN 2A) syndrome in whom a prophylactic thyroidectomy was performed, in relation to the recommendations of the American Thyroid Association (ATA). Methods A retrospective study of 14 patients with MEN 2A thyroidectomized between 2000 and 2017. We reviewed demographic, clinical, analytical and radiological data. Postoperative complications and long-term follow-up were analyzed. Results We treated eight boys and six girls with a median age of 5 years old (range 2-10). The predominant genetic mutation belonged to codon 634 (8/14, 57.14%). Total thyroidectomy (TT) without cervical lymphadenectomy was performed in all patients. A right upper parathyroidectomy was performed in one patient due to intraoperative suspicion of increased volume. Histological study revealed no alterations. Two patients presented transient hypocalcemia postoperatively and no patient had permanent hypocalcemia or nerve damage. Pathological anatomy confirmed medullary thyroid microcarcinoma in 5/14 patients: all carrying codon 634 mutation and three of them with preoperative basal calcitonin levels <20 pg/mL. No recurrences or metastases have been detected after a mean follow-up of 8 years. A patient with codon 634 mutation developed a unilateral pheochromocytoma at 25 years of age. No patient has presented hyperparathyroidism. Conclusions Prophylactic thyroidectomy without cervical lymphadenectomy is an effective and safe preventive treatment in patients with MEN 2A syndrome when it is performed by experienced surgeons in reference centers.

The RET C611Y mutation causes MEN 2A and associated cutaneous

BACKGROUND

Cutaneous lichen amyloidosis (CLA) has been reported in some multiple endocrine neoplasia type 2A (MEN 2A) families affected by specific germline RET mutations C634F/G/R/W/Y or V804M, as a characteristic of the clinical manifestation in ‘MEN 2A with CLA’, one of four variants of MEN 2A, which was strictly located in the scapular region of the upper back.

PATIENT FINDINGS

This study reports a large south-eastern Chinese pedigree with 17 individuals carrying the MEN 2A-harboring germline C611Y (c.1832G>A) RET mutation by Sanger sequencing. One individual presented MEN 2A-related clinical features, including typical CLA in the interscapular region; another individual exhibited neurological pruritus and scratching in the upper back but lacked CLA skin lesions. Both subjects presented with CLA or pruritic symptoms several years before the onset of medullary thyroid carcinoma (MTC) and/or pheochromocytoma. The remaining 15 RET mutation carriers did not exhibit CLA; of these, one presented with MTC and pheochromocytoma, nine with MTC only, two with elevated serum calcitonin and three younger subjects with normal serum calcitonin levels. This family’s clinical data revealed a later diagnosis of MTC (mean age, 45.9 (range: 23–73) years), a lower penetrance of pheochromocytoma (2/17, 11.8%) and CLA (1/17, 5.9%). However, no hyperparathyroidism and Hirschsprung disease were reported in this family.

SUMMARY AND CONCLUSIONS

This is the first description of a family with MEN 2A-related CLA due to a germline RET C611Y mutation, which might exhibit a novel and diversified genotype–phenotype spectrum in MEN 2A.

The Clinical Spectrum of Multiple Endocrine Neoplasia Type 2A with Cutaneous Lichen Amyloidosis in Ethnic Han Chinese

This study systematically reviewed previous literatures and analyzed the genotype-phenotype relationship between the multiple endocrine neoplasia type 2A (MEN 2A)-cutaneous lichen amyloidosis (CLA) and RET/OSMR/IL31RA mutations. RET/OSMR/IL31RA screening was performed on 8 RET-carriers from 3 independent Chinese MEN 2A families. Besides, 51 MEN 2A-CLA patients in 116 RET carriers from literatures were clustered and analyzed. Our results indicated that almost all MEN 2A-CLA patients exhibited CLA which was located in the scapular region and carried RET mutation at codon 634. Meanwhile, we firstly described MEN 2A-CLA here in Chinese Han patient with RET p.C634F mutation.

Surgical approaches in hereditary endocrine tumors

Endocrine tumors of thyroid, adrenal and parathyroid glands may be due to germline and inheritable mutations in 5-30% of patients. Medullary Thyroid Carcinoma, Pheochromocytoma, Paraganglioma, and Familial Primary Hyperparathyroidism are the most frequent entity. Hereditary endocrine tumors usually have a suggestive familial history; they occur earlier than sporadic variants, are multifocal, and have increased recurrence rates. They may be present as isolated variant or associated to other neoplasms in a syndromic setting. Genetic diagnosis should be preferably available before surgery because specific and targeted operative management are needed to achieve the best chance of cure. This review was aimed to discuss the surgical approaches for some of the most frequent hereditary endocrine tumors of thyroid, adrenal and parathyroid glands, focusing on medullary thyroid carcinoma, Pheochromocytoma, Paraganglioma and hereditary primary hyperparathyroidism (pHPT). Hereditary Medullary Thyroid Carcinoma is caused by RET mutations, and may be associated to Pheochromocytomas in MEN 2 setting. Total thyroidectomy and at least central neck nodal dissection is required. The availability of genetic screening allows prophylactic or early surgery in asymptomatic patients, with subsequent definitive cure. Hereditary Pheochromocytomas may be present in several syndromes (MEN 2, VHL, NF1, Paraganglioma/Pheochromocytoma syndrome); it may involve both adrenals; in these cases, a cortical sparing adrenalectomy should be performed to avoid permanent hypocorticosurrenalism. Hereditary Primary Hyperparathyroidism may frequently occur associated to MEN 1, MEN 2A, MEN 4, Hyperparathyroidism-Jaw Tumor Syndrome; it may involve all the parathyroid glands, requiring subtotal parathyroidectomy or total parathyroidectomy plus autotransplantation. In some cases, a selective parathyroidectomy might be performed.

RET mutation p.S891A in a Chinese family with familial medullary thyroid carcinoma and associated cutaneous amyloidosis binding OSMR variant p.G513D

There are no reports on the relationship between familial medullary thyroid carcinoma (FMTC) associated with cutaneous amyloidosis (CA) and RET or OSMR/IL31RA gene mutations. In this study, we investigated a Chinese family with FMTC/CA and found a recurrent RET c.2671T>G (p.S891A) mutation in six of 17 family members. Three of the six p.S891A mutation carriers presented with medullary thyroid carcinoma (MTC). Of them, three (two with and one without MTC) were diagnosed as having combined lichen/macular biphasic CA. We also identified a novel RET variant, c.1573C>T (p.R525W) in five members. Of them, three carriers had no evidence of thyroid/skin or basal serum/stimulated calcitonin abnormalities. In vitro cell proliferation assay indicated that oncogenic activity of RET p.S891A was slightly enhanced by p.R525W, whereas p.R525W alone had no effect on cell proliferation. Meanwhile, we identified a novel OSMR variant, c.1538G>A (p.G513D) in seven members. We noticed that three OSMR p.G513D carriers presenting with CA also had the RET p.S891A mutation. Our investigation indicated that the RET p.S891A mutation combined with OSMR p.G513D may underlie a novel phenotype manifesting as FMTC and CA.

Distribution of RET Mutations and Evaluation of Treatment Approaches in Hereditary Medullary Thyroid Carcinoma in Turkey

OBJECTIVE

This retrospective multicenter study, centrally conducted and supported by the Society of Endocrinology and Metabolism of Turkey, aimed to evaluate the impact of free RET proto-oncogene testing in medullary thyroid carcinoma (MTC) patients. Surgical timing, adequacy of the treatment, and frequency of prophylactic thyroidectomy (PTx) in mutation carriers were also assessed.

METHODS

Genetic testing for MTC and pheochromocytoma was conducted between July 2008 and January 2012 in 512 patients. Application forms and RET mutation analyses of these patients whose blood samples were sent from various centers around Turkey were assessed retrospectively. An evaluation form was sent to the physicians of the eligible 319 patients who had confirmed sporadic MTC, familial MTC (FMTC), multiple endocrine neoplasia type 2 (MEN2), or who were mutation carriers. Physicians were asked to give information about the surgical history, latest calcitonin levels, morbidity, mortality, genetic screening, and PTx among family members. Twenty-five centers responded by filling in the forms of 192 patients.

RESULTS

Among the 319 patients, RET mutation was detected in 71 (22.3%). Cys634Arg mutation was the most prevalent mutation (43.7%), followed by Val804Met in 18 patients (25.4%), and Cys634Tyr in 6 patients (8.5%). Among 192 MTC patients, the diagnosis was sporadic MTC in 146 (76.4%), FMTC in 14 (7.3%), MEN2A in 15 patients (7.9%), and MEN2B in one patient. The number of mutation carriers among 154 apparently sporadic MTC patients was 8 (5.2%). Ten patients were submitted to PTx out of twenty-four mutation carriers at a mean age of 35±19 years.

CONCLUSION

Turkish people have a similar RET proto-oncogene mutation distribution when compared to other Mediterranean countries. Despite free RET gene testing, the number of the PTx in Turkey is limited and relatively late in the life span of the carriers. This is mainly due to patient and family incompliance and incomplete family counselling.

Five Top Stories in Thyroid Pathology

CONTEXT

Thyroid carcinoma is the most common malignant tumor of endocrine organs, yet it only accounts for approximately 1% of all cancers in the United States with more than 35,000 new cases diagnosed each year and more than 450,000 people living with this disease. While most tumors can be diagnosed without much difficulty, a few tumor types, especially tumors with follicular pattern, sometimes pose a diagnostic challenge.

OBJECTIVE

To discuss morphologic, immunohistochemical, and molecular features of thyroid tumors. We also explore the clinicopathologic features of papillary microcarcinoma and medullary microcarcinoma and how the latter is related and differentiated from C-cell hyperplasia. Finally with the ever-growing list of organ systems involved in immunoglobulin (Ig) G4-related diseases, we discuss the still not completely explored IgG-4-related thyroid disease.

DATA SOURCES

Data were obtained from review of the pertinent peer-reviewed literature and institutional experience.

CONCLUSIONS

Histomorphologic evaluation still remains the gold standard for diagnosis in most cases of thyroid diseases. The application of ancillary studies such as immunohistochemistry and molecular diagnosis, including next-generation sequencing, is becoming more common.

Molecular diagnosis and comprehensive treatment of multiple endocrine neoplasia type 2 in Southeastern Chinese

Background

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited endocrine malignancy syndrome. Early and normative surgery is the only curative method for MEN 2-related medullary thyroid carcinoma (MTC). In patients with adrenal pheochromocytoma, cortical-sparing adrenalectomy (CSA) can be utilized to preserve adrenocortical function.

Methods

We present twenty-six of 33 MEN2 patients underwent prophylactic thyroidectomy with varying neck dissection and eight of 24 MEN2A patients with PHEO underwent adrenal-sparing surgery. Direct sequencing of entire RET exons was performed in all participants.

Results

The RET mutations (p.C634Y [n = 10], p.C634R [n = 9], p.C634F [n = 2], p.C618Y [n = 8], p.C618R [n = 3], and p.M918T [n = 1]) were confirmed in 20 symptomatic patients and identified in 13 at-risk relatives (RET carriers). Twenty-six of 33 MEN2 patients underwent thyroidectomies with neck dissections; the mean age at the time of the first thyroid surgery and the tumor diameter of the 6 RET carriers was decreased compared with 20 symptomatic patients (P < 0.001 and P = 0.007, respectively), while the disease-free survival was increased (80% vs.10%, P = 0.0001). Seven RET carriers who were declined surgery. One of 20 symptomatic patients with MTC bone metastases after surgery received vandetanib therapy for 20 months and responded well. Additionally, 8 of 24 MEN2A patients who initially had unilateral pheochromocytomas underwent CSA, 1 developed contralateral pheochromo cytomas 10 years later, then also accepted and also agreed to a CSA. None of the patients required steroid replacement therapy.

Conclusions

Based on our results, integrated RET screening and the pre-operative calcitonin level is an excellent strategy to ensure earlier diagnosis and standard thyroidectomy. CSA can be utilized to preserve adrenocortical function in patients with pheochromocytomas.

Electronic supplementary material

The online version of this article (doi:10.1186/s13053-015-0026-1) contains supplementary material, which is available to authorized users.

The genetics of endocrine neoplasia

The hereditary endocrine neoplasias are characterized by the development of benign or malignant tumors in more than one endocrine tissue. These tumors typically occur at a younger age than sporadic endocrine tumors and follow an autosomal dominant pattern of inheritance. Because of the age-related penetrance and extreme phenotypic variability both within and between families, clinicians cannot always rely on the family history to make the diagnosis. Recognition of the features of a hereditary endocrine syndrome can allow for appropriate and timely risk assessment, genetic counseling and genetic testing, and identification of at-risk family members who may benefit from early and regular screening.