Preoperative calcitonin testing improves the diagnosis of medullary thyroid carcinoma in female and male patients

AIM

Calcitonin (Ctn) measurement in patients with thyroid disease could potentially increase the detection rates of medullary thyroid carcinoma (MTC) but remains a controversial issue. The aim of this study was to evaluate routine preoperative Ctn measurements.

METHODS

All patients with thyroid surgery documented in the prospective StuDoQ|Thyroid registry between March 2017 and September 2020 were included. Cutoff levels for Ctn were determined with receiver-operating characteristic analyses to assess the preoperative diagnosis of MTC in subgroups for females and males.

FINDINGS

In 29 590 of 39 679 patients (75%) participating in the registry, routine preoperative Ctn testing was performed. In 357 patients (227 females and 130 males), histopathology confirmed MTC with a mean tumor size of 14.7 mm (±12.43). Biochemical cure was achieved in 71.4% of the patients. Ctn levels between 11 and 20 pg/mL were seen in 2.6% of the patients, and only 0.7% of the patients had Ctn levels above 21 pg/mL. Cutoff levels for the diagnosis of MTC were 7.9 pg/mL for females and 15 pg/mL for males (P < 0.001). The sensitivity and specificity for females were 95 and 98%, and 96 and 97% for males, respectively.

CONCLUSION

Routine Ctn testing is a reliable predictor for MTC and provides the opportunity for earlier thyroidectomy before lymph node metastases occur, resulting in a better prognosis. Females with Ctn levels >7.9 pg/mL and males >15 pg/mL without any other extrathyroidal sources for an elevated Ctn should be monitored. Thyroid surgery should be considered if Ctn levels are increasing or ultrasound detects suspicious thyroid lesions.

Germline RET Leu56Met Variant Is Likely Not Causative of Multiple Endocrine Neoplasia Type 2

Activating variants in the receptor tyrosine kinase REarranged during Transfection (RET) cause multiple endocrine neoplasia type 2 (MEN 2), an autosomal dominantly inherited cancer-susceptibility syndrome. The variant c.166C>A, p.Leu56Met in RET was recently reported in two patients with medullary thyroid cancer (MTC). The presence of a pheochromocytoma in one of the patients, suggested a possible pathogenic role of the variant in MEN 2A. Here, we present clinical follow up of a Danish RET Leu56Met cohort. Patients were evaluated for signs of MEN 2 according to a set of predefined criteria. None of the seven patients in our cohort exhibited evidence of MEN 2. Furthermore, we found the Leu56Met variant in our in-house diagnostic cohort with an allele frequency of 0.59%, suggesting that it is a common variant in the population. Additionally, none of the patients who harbored the allele were listed in the Danish MTC and MEN 2 registries. In conclusion, our findings do not support a pathogenic role of the Leu56Met variant in MEN 2.

Survival and Long-Term Biochemical Cure in Medullary Thyroid Carcinoma in Denmark 1997-2014: A Nationwide Study

BACKGROUND

Survival of medullary thyroid carcinoma (MTC) subgroups in relation to the general population is poorly described. Data on the factors predicting long-term biochemical cure in MTC patients are nonexistent at a population level. A nationwide retrospective cohort study of MTC in Denmark from 1997 to 2014 was conducted, aiming to detect subgroups with survival similar to that of the general population and to identify prognostic factors for disease-specific survival and long-term biochemical cure.

METHODS

The study included 220 patients identified from the nationwide Danish MTC cohort between 1997 and 2014. As a representative sample of the general population, a reference population matched 50:1 to the MTC cohort was used.

RESULTS

Patients diagnosed with hereditary MTC by screening (hazard ratio [HR] = 1.5 [confidence interval (CI) 0.5-4.3]), patients without regional metastases (HR = 1.4 [CI 0.9-2.3]), and patients with stage I (HR = 1.3 [CI 0.6-3.1]), stage II (HR = 1.1 [CI 0.6-2.3]), and III (HR = 1.3 [CI 0.4-4.2]) disease had an overall survival similar to the reference population. On multivariate analysis, the presence of distant metastases (HR = 12.3 [CI 6.0-25.0]) predicted worse disease-specific survival, while the absence of regional lymph node metastases (odds ratio = 40.1 [CI 12.0-133.7]) was the only independent prognostic factor for long-term biochemical cure.

CONCLUSIONS

Patients with hereditary MTC diagnosed by screening, patients without regional metastases, and patients with stages I, II, and III disease may have similar survival as the general population. The presence of distant metastases predicted worse disease-specific survival, while the absence of regional metastases predicted long-term biochemical cure.

Multiple endocrine neoplasia 2 in Cyprus: evidence for a founder effect

PURPOSE

Multiple endocrine neoplasia type 2 (MEN2) affects patients with RET proto-oncogene mutations. This cohort study refers to patients who were diagnosed with familial medullary thyroid carcinoma (MTC) and underwent RET genetic testing in Cyprus between years 2002 and 2017.

METHODS AND PATIENTS

Forty patients underwent RET testing by Sanger sequencing of exons 10-11 and 13-16. Genotyping with STR genetic markers flanking the RET gene along with Y-chromosome genotyping and haplogroup assignment was also performed.

RESULTS

RET mutations were identified in 40 patients from 11 apparently unrelated Cypriot families and two non-familial sporadic cases. Nine probands (69.2%) were heterozygous for p.Cys618Arg, one (7.7%) for p.Cys634Phe, one (7.7%) for the somatic delE632-L633 and two (15.4%) for p.Met918Thr mutations. The mean age at MTC diagnosis of patients carrying p.Cys618Arg was 36.8 ± 14.2 years. The age of pheo diagnosis ranged from 26 to 43 years and appeared simultaneously with MTC in 5/36 (13.9%) cases. The high frequency of the p.Cys618Arg mutation suggested a possible ancestral mutational event. Haplotype analysis was performed in families with and without p.Cys618Arg. Six microsatellite markers covering the RET gene and neighboring regions identified one core haplotype associated with all patients carrying p.Cys618Arg mutation.

CONCLUSIONS

The mutation p.Cys618Arg is by far the most prevalent mutation in Cyprus followed by other reported mutations of variable clinical significance. The provided molecular evidence speculates p.Cys618Arg mutation as an ancestral mutation that has spread in Cyprus due to a possible founder effect.

Looking beyond the thyroid: advances in the understanding of pheochromocytoma and hyperparathyroidism phenotypes in MEN2 and of non-MEN2 familial forms

Over the last years, the knowledge of MEN2 and non-MEN2 familial forms of pheochromocytoma (PHEO) has increased. In MEN2, PHEO is the second most frequent disease: the penetrance and age at diagnosis depend on the mutation of RET Given the prevalence of bilateral PHEO (50% by age 50), adrenal sparing surgery, aimed at sparing a part of the adrenal cortex to avoid adrenal insufficiency, should be systematically considered in patients with bilateral PHEO. Non-MEN2 familial forms of PHEO now include more than 20 genes: however, only small phenotypic series have been reported, suggesting that phenotypic features of isolated hereditary PHEO must be better explored, and follow-up series are needed to better understand the outcome of patients carrying mutations of these genes. The first part of this review will mainly focus on these points. In the second part, a focus will be given on MEN2 and non-MEN2 familial forms of hyperparathyroidism (HPTH). Again, the management of MEN2 HPTH should be aimed at curing the disease while preserving an optimal quality of life by a tailored parathyroidectomy. The phenotypes and outcome of MEN1-, MEN4- and HRPT2-related HPTH are briefly described, with a focus on the most recent literature data and is compared with familial hypocalciuric hypercalcemia.

Evidence for the founder effect of RET533 as the common Greek and Brazilian ancestor spreading multiple endocrine neoplasia 2A

OBJECTIVES

About one-quarter of patients with medullary thyroid cancer (MTC) have inherited disease due to mutations in the RET gene. A rare mutation in exon 8 (G533C) of RET, previously described in a large Brazilian family with MEN2A, also appeared to be clustering in Greece, whereas it was rarely reported in other ethnic groups. The aim of this study was to identify a possible common ancestry between these carriers.

PATIENTS AND METHODS

Twelve RET G533C mutation carriers, four randomly selected from the Brazilian cohort and eight from apparently unrelated Greek families, were studied for a possible common ancestral origin. RET flanking microsatellite markers at chromosome 10q (D10S197, D10S196, D10S1652 and D10S537) were used.

RESULTS

Genomic DNA analysis using these markers showed that many of these apparently unrelated individuals shared a common haplotype indicating a common ancestral origin.

CONCLUSION

Our data suggest that Brazilian and Greek patients with MTC carrying the G533C mutation in exon 8 of RET gene originate from a common ancestor. Due to historical reasons, we speculate that the more plausible explanation for the origin of this mutation is in Greece.

Epidemiology and Clinical Presentation of Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor originating from the thyroid C cells producing mainly calcitonin (CTN) used as tumor marker. MTC occurs either sporadic (75%) or in a hereditary form (multiple endocrine neoplasia type 2, MEN2), due to germline mutations in the RET proto-oncogene. The discovery of an MTC in a patient has several diagnostic implications involving a specific strategy: preoperative evaluation of the tumor marker CTN and the extent of the disease, classification of MTC as sporadic or hereditary by DNA testing, and screening for associated endocrinopathies in hereditary MTC. Elevated CTN is a highly sensitive and specific tumor marker for diagnosis and follow-up of MTC. CTN is directly related to the tumor mass. In patients with nodular thyroid disease, diagnosis of MTC could be made by CTN determination as an indicator of tumor burden in conjunction with fine-needle aspiration. Patients with confirmed sporadic or hereditary MTC should have a total thyroidectomy and depending on the preoperative CTN value and the extent of disease additional dissection of the lymph nodes in the central and lateral neck compartment. In MEN 2 patients diagnosed by screening, the time of prophylactic thyroidectomy depends on RET mutation and CTN level.

Presence of the RET Cys634Tyr mutation and Gly691Ser functional polymorphism in Iranian families with multiple endocrine neoplasia type 2A

PURPOSE

Multiple Endocrine Neoplasia type 2A (MEN2A) is a complex autosomal dominant inherited syndrome characterized by medullary thyroid carcinoma (MTC), pheochromocytoma and primary parathyroid hyperplasia. In patients with only one or two clinical features, identification of a germ line RET (REarranged in Transfection) mutation is required to make the diagnosis and initiate genetic counseling.

METHODS

We analyzed blood DNA from three Iranian families with three generations of MEN2A including 20 affected individuals with MTC and four with pheochromocytoma. RET hotspots were amplified in probands and sequenced for mutation detection.

RESULT

The causative mutation in all families was found to be the Cys634Tyr missense substitution. The presence of a functional SNP resulting in Gly691Ser was also detected in exon 11 of 15 affected cases. Four patients showed both of these RET variations.

CONCLUSION

Our study shows that the Cys634Tyr missense substitution and the Gly691Ser polymorphism are recurrent in Iranian patients, since our families are unrelated. All asymptomatic carriers of the Cys634Tyr high-risk activating mutation were referred for prophylactic thyroidectomy.

Papillary thyroid carcinoma and multiple endocrine neoplasia type 2

INTRODUCTION

Papillary thyroid carcinoma (PTC) is exceptional in MEN 2.

RESULTS

The analysis in 135 patients revealed two PTC, without C-cell pathology; both being positive for V804M mutation (RET proto-oncogene).

CONCLUSIONS

Few data are available about PTC in MEN 2, and without C-cell pathology is even less common. More studies are needed to correlate genetics and histology, and even for assessing PTC as only manifestation of MEN 2.

Therapeutic Effectiveness of Screening for Multiple Endocrine Neoplasia Type 2A

CONTEXT

Although technological progress revolutionized detection of genetic predisposition to medullary thyroid cancer (MTC), carriers of mutations of disparate risks may not have benefitted alike from screening.

OBJECTIVE

This investigation aimed at assessing the achievements of screening for multiple endocrine neoplasia type 2A (MEN 2A) in Germany and identifying current challenges.

DESIGN

This was a retrospective analysis comprising 455 carriers at risk of MEN 2A screened and operated between 1963 and 2014.

SETTING

The setting was tertiary surgical referral centers.

PATIENTS

Included were 175 carriers of American Thyroid Association (ATA) level C mutations (codon 634); 116 carriers of ATA level B mutations (codons 609, 611, 618, 620 and 630); and 164 carriers of ATA level A mutations (codons 768, 790, 791, 804 and 891).

INTERVENTIONS

The intervention was thyroidectomy.

MAIN OUTCOME MEASURES

Main outcome measures were percentage of index patients among all carriers and percentage of MTC, node-positive MTC, and biochemical cure among non-index patients.

RESULTS

The percentage of index patients among all carriers fell from 50% (ATA level C) and 100% (ATA levels B and A) to 16, 29, and 31%, respectively. Among non-index patients, the percentage of MTC fell for ATA levels C and B but not for ATA level A mutations. The corresponding percentage of node-positive MTC declined since 1963 from 100 to 0% (ATA level C) and since 1995 from 67 to 33% (ATA level B) and from 11 to 10% (ATA level A), whereas biochemical cure increased from 0 to 100% since 1963 (ATA level C), and since 1995 from 71 to 78% (ATA level B) and from 95 to 100% (ATA level A).

CONCLUSIONS

Screening efforts need to focus on sporadic-appearing MTC to deplete the pool of unrecognized carriers of ATA level B and A mutations and enable earlier pre-emptive thyroidectomy in their offspring.

Genetic screening of patients with medullary thyroid cancer in a referral center in Greece during the past two decades

OBJECTIVE

Mutations in the RET gene are responsible for hereditary medullary thyroid cancer (MTC) and may vary between ethnic groups. We report the spectrum of mutations detected in patients with MTC in a referral center in Greece.

PATIENTS AND METHODS

Screening for RET mutations was performed in 313 subjects from 188 unrelated families: 51 patients had clinical suspicion for familial disease, 133 were apparently sporadic, four patients had only C cell hyperplasia, and 125 were family members. Exons 8, 10, 11, and 13-16 were screened.

RESULTS

A total of 58 individuals (30.85%) were RET mutations carriers, 120 (63.8%) were finally classified as sporadic, 13 apparently sporadic cases (9.8%) were identified with RET mutation: ten carried the exon 8 at codon 533 mutation (previously reported), two the exon 14 at codon 804 mutation, and one the exon 13 at codon 768 mutation. Six patients (3.19%) with clinical features of multiple endocrine neoplasia type 2A and negative for RET mutations were classified as 'unknown cause'. The mutations of hereditary cases were as follows: 21 cases (36.2%) in exon 8 codon 533, 19 (32.8%) in exon 11 codon 634, nine (15.5%) in exon 10, five (8.6%) in exon 16, three (5.2%) in exon 14 codon 804, and one in exon 13 codon 768 (1.7%).

CONCLUSION

The spectrum of RET mutations in Greece differs from that in other populations and the prevalence of familial cases is higher. The exon 8 (Gly533Cys) mutation was the most prevalent in familial cases unlike other series, followed by exon 11 (codon 634) mutations which are the most frequent elsewhere. The wide application of genetic screening in MTC reveals new molecular defects and helps to characterize the spectrum of mutations in each ethnic group.

Genetic basis of familial isolated hyperparathyroidism: a case series and a narrative review of the literature

Primary hyperparathyroidism is a heterogeneous clinical entity. In the clinical setting, the diagnosis and management of familial isolated hyperparathyroidism (FIHP) and other familial hyperparathyroidism (FHPT) forms continue to rely on clinical, laboratory, and histological findings, with careful examination of the family. In this article, we report a case series of FIHP in a four-generation Greek family, with no identifiable gene mutations. Clinical approach and long-term follow-up are discussed and a narrative review of the genetic basis of this entity has been performed.

Molecular epidemiology of multiple endocrine neoplasia 2: implications for RET screening in the new millenium

OBJECTIVE

Twenty years ago, the groundbreaking discovery that rearranged during transfection (RET) mutations underlie multiple endocrine neoplasia 2 (MEN2) and familial medullary thyroid cancer (FMTC) ushered in the era of personalized medicine. MEN2-associated signs, taking time to manifest, can be subtle. This study sought to clarify to what extent conventional estimates of 1:200 000-500 000 underestimate the incidence of RET mutations in the population.

DESIGN

Included in this retrospective investigation were 333 RET carriers born between 1951 and 2000 and operated on at the largest German surgical referral center (286 carriers) or elsewhere (47 carriers).

METHODS

To estimate the incidence of RET mutations, the number of RET carriers born in Germany in five decades (1951-1960, 1961-1970, 1971-1980, 1981-1990, and 1991-2000) was divided by the corresponding number of German live births.

RESULTS

Owing to improved diagnosis and capture of FMTC and MEN2 patients, minimum incidence estimates increased over time: overall from 5.0 (1951-1960) to 9.9 (1991-2000) per million live births and year (P=0.008), and by American Thyroid Association/ATA class from 1.7 to 3.7 for ATA class C (P=0.008); from 1.8 to 2.7 for ATA class A (P=0.017); from 1.5 to 2.2 for ATA class B (P=0.20); and from 0 to 1.4 for ATA class D mutations per million live births and year (P=0.008). Based on 1991-2000 incidence estimates the prevalence in Germany is ∼1:80 000 inhabitants.

CONCLUSIONS

The molecular minimum incidence estimate of ≈1:100 000 was two- to fivefold greater than conventional estimates of 1:200 000-500 000.

Hereditary hyperparathyroidism syndromes

Primary hyperparathyroidism is a common endocrine disorder, resulting from a persistent hypercalcemia along with an inadequate secretion of parathyroid hormone. In approx 95% of cases, it occurs sporadically; rarely, it is part of familial syndromes. These inherited syndromes typically present at an earlier age than the nonheritable form and occur with equal frequencies in both sexes. The differential diagnosis is often difficult, but it is of fundamental importance for the management of patients and their family. The availability of specific genetic tests has improved the diagnostic accuracy allowing early diagnosis in asymptomatic family members. Before the advent of genetic testing, a definitive diagnosis could be made only in symptomatic cases based on clinical data and family history.

Clinical and prognostic implications of the genetic diagnosis of hereditary NET syndromes in asymptomatic patients

Neuroendocrine tumors (NETs) can be sporadic or they can arise in complex hereditary syndromes. Patients with hereditary NETs can be identified before the development of tumors by performing genetic screenings. The aim of the study was to evaluate the clinical and prognostic impact of a preclinical genetic screening in subjects with hereditary NET syndromes. 46 subjects referred for hereditary NET syndrome [22 MEN1, 12 MEN2, 12 Familial Paragangliomatosis (FPGL)] were enrolled and divided in 2 groups (group A, 20 subjects with clinical appearance of NET before the genetic diagnosis; group B, 26 subjects with genetic diagnosis of hereditary NET syndromes before the clinical appearance of NETs). The main outcome measures were severity of disease, prognosis, and survival. The rate of surgery for MEN1-, MEN2-, FPGL4-related tumors was 90% in group A and 35% in group B (p<0.01). Both symptoms related to tumors and symptoms related to therapies were significantly less frequent in group B than in group A (p<0.05). Tumor stage was locally advanced or metastatic in 50% of group A and in no one of group B (p<0.01). The mortality rate was 25% in group A and 0% in group B (p<0.05). An early genetic screening for hereditary NET syndromes results in an improvement in clinical presentation and morbidity. A potential impact of the genetic screening on the mortality rate of these subjects is suggested and needs to be investigated in further and more appropriate studies.

The clinical spectrum of multiple endocrine neoplasia type 2a caused by the rare intracellular RET mutation S891A

BACKGROUND

Germline missense mutations of the RET protooncogene cause a clinical spectrum called multiple endocrine neoplasia (MEN) type 2. A strong genotype-phenotype correlation results in major implications for the clinical approach. More information on less common mutations is needed to advance specific guidance.

PATIENTS AND METHODS

We report individualized patient information on 36 carriers of the intracellular RET gene mutation S891A from three centers and clustered data of 38 former patients reported in the literature in nine additional studies.

RESULTS

S891A mutation accounts for up to 5% of all patients to date reported with RET mutations and 16% of those hitherto reported with intracellular mutations. S891A mutation caused medullary thyroid cancer (MTC) in 69.4%, pheochromocytoma in 2.8%, and parathyroid hyperplasia in 8.3% of the 36 patients of this case series and in 63.5, 4.1, and 4.1%, respectively, for the entire groups of 74 patients. The youngest age of onset for MTC in this group was 17 yr (median, 46 yr; range, 17-80 yr), for pheochromocytoma 46 yr (median, 46 yr), and for parathyroid hyperplasia 17 yr (median, 20 yr, range, 17-46 yr). Persistence of MTC was described in 14.3% of patients with available follow-up. Additional findings included corneal nerve thickening in three of 74 patients (4.1%).

CONCLUSION

This intracellular mutation can initiate the full spectrum of MEN2a, initiates MTC at an early age, and causes recurrence and death if undertreated. We recommend stringent adherence to established guidance in MEN2a in this rare mutation.

Genetics of pheochromocytoma and paraganglioma in Spanish patients

CONTEXT

The presence of familial history in pheochromocytoma/paraganglioma patients, including syndromic antecedents, leads in the majority of cases to a positive genetic testing for mutations in one of the major susceptibility genes described so far. Furthermore, it has been reported that in the absence of familial antecedents, about 11-24% of patients also carry a mutation in one of these related genes. In these cases, other clinical aspects like bilaterality, multiplicity, location of the tumors, or age at onset can help to recognize the underlying genes involved.

OBJECTIVE

The objective of the study was to discuss clinical criteria helpful in the genetic diagnosis, placing special emphasis on apparently sporadic cases.

DESIGN

Two hundred thirty-seven nonrelated probands were analyzed for the major susceptibility genes: VHL, RET, SDHB, SDHC, and SDHD. Genetic characterization included both point mutation analysis and gross deletions in the SDH genes performed by multiplex PCR.

RESULTS

As expected, all syndromic probands were genetically diagnosed with a mutation affecting either RET or VHL. A total of 79.1% (19 of 24) and 18.4% (31 of 168) of patients presenting with either nonsyndromic familial antecedents or apparently sporadic presentation were found to carry a mutation in one of the susceptibility genes. Finally, we found a Spanish founder effect for two mutations: SDHB c.166_170delCCTCA and SDHD c.129G>A.

CONCLUSIONS

Germline mutations are rare in apparently sporadic probands diagnosed after age 40 yr (3.9% in our series) and mainly involve SDHB. Therefore, we recommend prioritizing SDHB genetic testing in patients developing isolated tumors at any age, especially those with extraadrenal location or malignant behavior.

Inherited endocrinopathies: an update

Inherited endocrinopathies, including multiple endocrine neoplasia type 1 (MEN-1), multiple endocrine neoplasia type 2 syndromes (MEN-2A, MEN-2B, familial medullary thyroid carcinoma), and inherited syndromes with pheochromocytoma (von Hippel-Lindau disease, neurofibromatosis type 1, others), comprise a heterogeneous group of cancer susceptibility syndromes that affect one or more components of the endocrine system. During the past several years, novel findings regarding genotype-phenotype correlation have highlighted the importance of establishing a genetic diagnosis in the treatment of these diseases. Here, we present a case-based review of recent advances in the genetics, diagnosis and management of inherited endocrinopathies.

[Multiple endocrine neoplasia type 2]

Multiple endocrine neoplasia type 2 (MEN2) is an hereditary disease with a prevalence of 1/5000. Three phenotypic variants have been identified: MEN2A associates medullary thyroid carcinoma (MTC) to pheochromocytoma in about 20-50% of cases and to primary hyperparathyroidism in 5-20% of cases; MEN2B associates MTC to pheochromocytoma in 50% of cases, to marphanoid habitus and to mucosal and digestive ganglioneuromatosis whereas in familial isolated medullary thyroid carcinoma (FMTC), the other components of the disease are absent. In MEN2, natural history of the disease and a common embryologic origin (neural crest) may explain the phenotypes observed in the organ involved, beginning from the stage of hyperplasia to adenoma and cancer. MEN2 is an inherited autosomal dominant disease with a complete penetrance, related to germline mutation in the proto-oncogene RET. MTC represent the most frequent circumstance of diagnosis. Pheochromocytoma and HPT may reveal the disease unfrequently and are systematically associated to undiagnosed MTC which is present yet. Analysis of the RET gene allows to confirm the diagnosis of MEN2 by identifying the causal germline mutation. Management of MEN2 patients include thyroidectomy associated to cervical central and bilateral lymph nodes dissection for MTC, unilateral adrenalectomy for unilateral pheochromocytoma or bilateral adrenalectomy when both glands are involved, and selective resection of pathologic parathyroid glands for HPT. Familial genetic screening detects at risk subjects who will develop the disease and allows to manage them at the earliest stage of the disease by perform early or prophylactic thyroidectomy such giving them the best chance of cure. Prognosis of MEN2 is mainly related to the stage-dependant prognosis of MTC, thus pointing the necessity of a complete thyroid surgery for index cases with MTC and the earliest thyroidectomy for screened at risk subjects.

Prophylactic thyroidectomy in pediatric carriers of multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma: mutation in C620 is associated with Hirschsprung's disease

PURPOSE

Prophylactic total thyroidectomy is now recommended after having confirmed RET mutations in children of parents with multiple endocrine neoplasia type 2 or familial medullary thyroid carcinoma. We reviewed our experience to determine the incidence of medullary thyroid carcinoma with respect to age at surgery, the location of the mutation, and its association with Hirschsprung's disease (HD).

METHODS

A retrospective review from 1996 to 2005 revealed 20 children with genetic screening for multiple endocrine neoplasia type 2A or familial medullary thyroid carcinoma who underwent a prophylactic total thyroidectomy with parathyroid gland preservation.

RESULTS

The median age of the 20 patients (9 boys and 11 girls) included in this study was 8.2 years (range, 3.7-16.9 years) at the time of their surgery. Final pathology revealed normal thyroid tissue (n = 3; median age, 5.9 years), C-cell hyperplasia (n = 13; median age, 10 years), or medullary thyroid carcinoma (n = 4; median age, 8 years). Four children, all with mutations in C620, had a previous diagnosis of HD. At a median follow-up of 3.7 years (range, 1 month to 8.4 years), all patients were well and cancer free.

CONCLUSIONS

There is no correlation between histologic findings and median age at surgery. Hirschsprung's disease was found in 50% of the patients with the RET mutation in C620. In children of C620 parents, symptoms of HD should be actively sought, and if such are found, rectal biopsies should be performed even if mutation results are not yet available. Based on the age of the earliest cancer and the safety of total thyroidectomy, children should promptly undergo surgery after genetic screening and before their fifth year of life.

Genotype-phenotype correlations in Hungarian patients with hereditary medullary thyroid cancer

The genotype and phenotype characteristics of Hungarian patients with RET proto-oncogene mutations operated on for hereditary medullary thyroid cancer (MTC) were studied. The genetic screening was performed in two centers and 40 patients with hereditary MTC or C-cell hyperplasia (CCH) from 18 unrelated families were analyzed. One patient having a mutation in exon 16 (Met918Thr) presented with the MEN2B phenotype, six patients from two families had hereditary MTC without pheochromocytoma (pheo) and primary hyperparathyroidism (PHPT), whereas 33 patients from 15 families showed the MEN2A phenotype. Two different mutations were identified in exon 10 (Cys609Tyr and Cys609Ser), five different mutations were present in exon 11 (Cys634Phe, Cys634Arg, Cys634Tyr, Cys634Trp and Cys634Ser), and two different mutations were localized in exon 14 (Val804Met and Val804Leu). Mutations in exon 10 were associated with hereditary MTC (Cys609Tyr) or with MEN2A syndrome (Cys609Ser). Mutations in exon 11 were always associated with the MEN2A phenotype. PHPT was present in one patient with mutation in exon 14 (Val804Met), whereas all other patients affected with mutations in exon 14 had hereditary MTC without PHPT and/or pheos.

Medullary Thyroid Cancer

The goal in managing patients who have MTC is to detect and surgically remove disease at an early stage. Tumor marker-based biochemical screening and DNA-based genetic screening have created the opportunity for effective prophylactic surgery in patients at risk for hereditary MTC. Complete surgical resection is critical for cure because cervical reoperation for persistent or recurrent disease benefits only select patients. With the advent of therapies that target the RET-activated pathways, new hope may be emerging for patients who have locally advanced or metastatic disease.

[Clinical and genetic profile of patients with medullary thyroid cancer treated in the Cancer Centre--Institute of Oncology in Warsaw]

INTRODUCTION

The aim of this study was to analyse the distribution and frequency of mutations and their correlations with clinical phenotypes of patients with MTC, to reveal the differences between sporadic and familial type of MTC, and to describe the phenotypes of patients.

MATERIALS AND METHODS

212 patients with medullary thyroid cancer (MTC) were treated in Cancer Centre in Warsaw between 1997 and 2005. In most patients, DNA isolated from peripheral blood leukocytes was tested for RET gene mutations by sequencing and accordingly MTC form was assessed. Genetic testing was performed in the relatives of patients with familial MTC in order to distinguish asymptomatic mutation carriers from noncarriers.

RESULTS

RET gene mutations were identified in 46 patients (22%). The others were found noncarriers and sporadic MTC was diagnosed. MEN 2A/FMTC syndrome (multiple endocrine neoplasia type 2A/ familial type of MTC) was diagnosed in 44 patients, MEN 2B syndrome (multiple endocrine neoplasia type 2B) in 2 patients. In patients with sporadic and familial MTC, age at diagnosis and multifocal occurrence was analysed, and the results were found to be in accordance with those of other research centres. However, the distribution and frequency of mutations, as well as some clinical data, such as the frequency of pheochromocytoma occurrence as the first manifestation of MEN syndrome, differed from the published data, and further studies are necessary to reveal the reasons of these differences.

CONCLUSIONS

DNA testing for RET gene mutations is reliable as a diagnostic tool and therefore it should be performed for screening of all patients with MTC or other diseases of MEN syndrome.

Hereditary medullary thyroid cancer in Slovenia – genotype-phenotype correlations

BACKGROUND

Medullary thyroid cancer (MTC) is a rare endocrine tumor that may be sporadic or inherited in settings of MEN2A, MEN2B and FMTC. Germline point mutations in the RET proto-oncogene are responsible for tumor occurrence, inheritance and great clinical variability. The aim of this study was to correlate the genotype and phenotype of patients with hereditary MTC (age at diagnosis, sex, TNM classification and clinical features).

PATIENTS

Between 1997 and 2003 genetic testing was performed in 69 out of 98 patients with "sporadic" MTC. Carriage of mutation was found in 14 (20.2%) patients (index patients) and in 16 out of 31 (51.6%) of their relatives. One patient with MEN2B and codon 918 mutation was excluded from further analysis.

METHODS

Genomic DNA was isolated from peripheral blood leukocytes. Exons 10, 11, 13, 14, 15 and 16 of the RET proto-oncogene were amplified in polymerase chain reactions. Point mutations of the RET gene were detected with single-strand conformation analysis and DNA sequencing. Detected mutations were confirmed with restriction enzyme analysis.

RESULTS

Codon 634 mutations were detected in 15 patients (50%; aged 18-76 years; 6 families), codon 618 in nine patients (30%; aged 12-65 years; 4 families) and codon 790 in five patients (16.6%; aged 16-74 years; 3 families). The median age at diagnosis was 31 +/- 17.3, 33 +/- 15.9 and 36 +/- 23.8 years for patients with codon 618, 634 and 790 mutations. Selected by sex, females with codon mutations 618 and 634 versus 790 had median age at diagnosis of 34.5 +/- 15.6 years and 43.5 +/- 22.9 years, whereas the inverse result was observed in males (26.5 +/- 18.0 versus 16 years). The male/female ratio was 1:2 for patients with codon 618 and 634 mutations and 1:4 for patients with codon 790 mutations. Some of the data suggested correlation between specific genotypes, tumor size, stage of MTC and age at diagnosis. Pheochromocytoma (12 out of 15 patients) and primary hyperparathyroidism (6 out of 15 patients) were diagnosed solely in patients with codon 634 mutations. One patient with FMTC and Hirschprung disease was found in a family with codon 618 mutations.

CONCLUSION

Correlation between tumor size, stage of MTC at diagnosis in view of patient's age, and specific genotype were indicated in our limited series and were more evident in female patients with codon 790 mutations. Later onset and a probably less aggressive course of MTC in these patients than in patients with other mutations should be considered in planning prophylactic thyroid surgery. MEN2A syndrome was related solely to codon 634 mutations.

Clinical manifestations of familial medullary thyroid carcinoma

We conducted a large-scale nation-wide questionnaire survey to ascertain the status of familial medullary thyroid carcinoma (MTC) in Japan in 2002. Out of a total of 271 MTC cases (male to female ratio 1:1.4), multiple endocrine neoplasia (MEN) 2A accounted for 83 cases (30.6%), familial MTC (FMTC) for 14 cases (5.1%), MEN for 11 cases (4.1%), and sporadic MTC for 163 cases (60.1%). Mean age at the time of diagnosis was 35.6 in MEN2A, 34.6 in FMTC, 30.5 in MEN2B, and 47.6 in sporadic MTC. Forty-five percent of MEN2A patients had pheochromocytoma and 11% of MEN2A patients had parathyroid disorders when MTC was diagnosed. Finally, the RET oncogene test yielded the largest number of initial findings that led to diagnosis of familial MTC.

Population-based study of familial medullary thyroid cancer

BACKGROUND

We wanted to carry out a population-based study on medullary thyroid cancer (MTC) in order to quantify familial risks.

METHODS

MTC was studied in the Swedish Family-Cancer Database, updated in 1999 to cover individuals and offspring, born after 1934 with their biological parents, totaling 9.6 million persons. Cancer data were obtained from the Swedish Cancer Registry from year 1958 to 1996 and included 2,435 thyroid cancers among offspring.

RESULTS

65 offspring were identified with MTC, which was coded as a separate entity since 1985. 62% had neither affected parent nor sib. Most familial cases were diagnosed at ages 15 to 24 and sporadic cases 25 years later. The familial SIRs of MTC were 3,080 and 3,650 when either a parent or a sib had MTC; when both had MTC the SIR was 35,800. All the familial risks were highest in young age groups, 0-9 years. MEN 2 or MEN 2-like families were considered when one family member had a TC and an adrenal pheochromocytoma. SIR of MTC in offspring was 61,000 when a parent had a MEN 2-like cancer and a sib had MTC.

CONCLUSIONS

We described familial and sporadic MTC in a population-based database. The familial risks of MTC may be the highest ever reported in population based studies.

[From gene to disease; from the RET gene to multiple endocrine neoplasia types 2A and 2B, sporadic and familial medullary thyroid carcinoma, Hirschsprung disease and papillary thyroid carcinoma]

The RET gene encodes a receptor tyrosine kinase involved in normal and neoplastic development of neural crest cell lineages. Activating RET mutations are present in patients with multiple endocrine neoplasia types 2A and 2B (MEN2A, 2B) and in familial medullary thyroid carcinoma (FMTC) patients, whereas inactivating RET mutations are found in patients with Hirschsprung (HSCR) disease. In particular for MEN2A and FMTC, the clinical management largely depends on the specific mutation found.

Prophylactic thyroidectomy, based on direct genetic testing, in patients at risk for the multiple endocrine neoplasia type 2 syndromes

Since the discovery that germ-line mutations in the RET protooncogene are responsible for the multiple endocrine neoplasia (MEN) syndromes types 2A and 2B, prophylactic thyroidectomy has been recommended for MEN patients to prevent medullary thyroid carcinoma (MTC). In this report, we present the medium-term follow up results on the earliest group of 18 patients having prophylactic thyroidectomy for MEN 2A. There were no operative complications. Microscopic or grossly evident MTC was present in 14 (78%) of the resected patients. None of the patients had metastasis of their MTC to regional lymph nodes. At three years' follow up, there is no evidence of residual or recurrent MTC, based on biochemical testing. We conclude that prophylactic thyroidectomy, based on direct DNA testing for RET gene mutations, is an effective and safe way to manage MTC in patients with MEN 2A.

Medullary thyroid carcinoma (MTC)--clinical and molecular aspects on the basis of own experience

In our clinic 19615 patients were operated over 25 years on for goiter. Malignant thyroid neoplasms were found in 1049 (5.3%) patients including 875 (83.4%) women and 174 (16.6%) men. Sixty two adult patients (42 women and 20 men were operated on for medullary thyroid carcinoma (MTC). Thyroid cancer was diagnosed in this group pre or intraoperatively in 44 (71%) patients and postoperatively, on histologic examination, in 18 (29%) patients. These patients were reoperated. Radical operations (total thyroidectomy with regional lymph node removal) were conducted in 43 (69.3%) patients and palliative ones in 19 (30.7%) patients. After MTC surgery, MEN 2A (MTC and an adrenal tumor) were diagnosed by means of imaging techniques (USG, CT) in 6 (9.7%) patients. All adrenal tumors were unilateral. Five of these patients were operated, and pheochromocytoma was confirmed by histopathologic examination. Two years after the MTC operation, 1 women was lost to follow-up. After a year, she was admitted to hospital for severe hypertension and died of cerebral hemorrhagia. Pheochromocytoma was revealed by autopsy. All patients were treated complementarily after the MTC operation. Different combinations of teleradiotherapy, chemotherapy and substitutive doses of levothyroxine were used. Ten (23.2%) of 43 patients operated radically were reoperated 1-3 years after the first operation due to loco-regional tumor recurrence. Radical reoperations were performed in 4 patients, and palliative ones in 6. Over a 0.5-23-year follow-up period, 26 (41.9%) patients died, including 20 of cancer, and 6 of other reasons. Four out of 36 living patients have clinical or biochemical symptoms of neoplastic disease. The follow-up period of MEN 2 patients operated on ranged from 1 to 6 years. Up to now, no tumor in the second adrenal gland has been diagnosed in any of these patients. Genetic (molecular) tests performed in 31 out of 36 living patients revealed mutations of RET gene in 4 (12.9%).

[Pheochromocytoma associated with multiple endocrine neoplasia 2A and sporadic: differential characteristics]

BACKGROUND

To study distinctive clinical features of pheochromocytoma in the setting of multiple endocrine neoplasia type 2A (MEN 2A) in comparison with sporadic pheochromocytoma.

PATIENTS AND METHOD

All patients diagnosed of sporadic pheochromocytoma (n = 29) and in the setting of MEN 2A (n = 16) between 1976 and 1998 in a tertiary hospital were included in the study. The following variables were compared: age at diagnosis, symptoms, presence and characteristics of hypertension, size of the tumor, localization and malignancy. The accuracy of diagnostic tests was also evaluated.

RESULTS

The pheochromocytoma associated to MEN 2A had a higher prevalence in our study (35.5%) and the diagnosis was performed earlier than for sporadic pheochromocytoma (29.1 [7.8] vs. 47,5 [10. 9] years; p < 0.001). Other distinctive features in comparison with sporadic pheochromocytoma were: bilaterality (81.25 vs. 3.44%; p < 0. 001), absence of symptoms (44 vs 11%; p < 0.05) and paroxysmal hypertension. Concerning the diagnostic tests, it must be noted the low sensitivity (60%) of vanillylmandelic acid in MEN 2A.

CONCLUSIONS

The pheochromocytoma in the setting of MEN 2A is diagnosed at younger age and frequently asymptomatic and bilateral. In view of the high prevalence of MEN 2A in our country, a genetic analysis should be performed in all patients with pheochromocytoma, especially when it is bilateral.

Presymptomatic detection and treatment of Japanese carriers of the multiple endocrine neoplasia type 2A gene

DNA extracted from the peripheral blood leukocytes of 36 members of five families with multiple endocrine neoplasia (MEN) type 2A was analyzed for mutations of exons 10, 11, 13, 14, and 16 of the RET proto-oncogene by nonisotopic polymerase chain reaction-single-strand conformation polymorphism analysis and automated DNA sequencing. Germline mutations were found in all 9 of the affected individuals and in 6 of the 27 individuals of unknown status. A 70-year-old man who had been completely asymptomatic before genetic diagnosis underwent left adrenalectomy and total thyroidectomy, and was found to have pheochromocytoma and multifocal micromedullary thyroid carcinoma (MTC). A 32-year-old man and a 15-year-old boy, with elevated calcitonin levels detected by the C-cell-stimulation test, but no evident thyroid tumor, underwent total thyroidectomy. Histopathological diagnosis revealed multiple micro MTCs. A 7-year-old girl without evidence of a thyroid tumor or an elevated calcitonin level is being followed up. The remaining two subjects with an evident thyroid tumor and elevated calcitonin levels refused surgery. These results suggest that genetic screening for MEN type 2 afflicted family members can facilitate the presymptomatic detection of gene carriers. Thus, we must carefully evaluate whether immediate prophylactic total thyroidectomy is indicated for gene carriers of MEN 2A without an evident thyroid tumor or elevated calcitonin levels.

Genetic testing in multiple endocrine neoplasia and related syndromes

Multiple Endocrine Neoplasia (MEN) syndromes are inherited diseases characterised by endocrine tumours occuring as autosomal dominant genetic diseases with high penetrance. In MEN1, most tumours affect the parathyroids, endocrine pancreas, anterior pituitary, and adrenal glands. The MEN1 gene has been cloned recently and encodes a nuclear protein without known function so far. More than 200 germline mutations have been identified in MEN1 patients throughout the entire coding sequence and no genotype-phenotype correlation has been found. Now, MEN1 gene screening is a powerful tool in pre-symptomatic diagnosis for MEN1 patients and those with inherited MEN1 related syndromes. MEN2 refers to the inherited forms of medullary thyroid carcinoma (MTC) which is associated with phaechromocytoma and parathyroid tumours in MEN2A, phaechromocytoma and mucosal neuromas in MEN2B. Familial isolated MTC is characterised by MTC only, and the three variants of MEN2 are related to germline missense mutations of the RET proto-oncogene, which encodes a tyrosine-kinase receptor. Germline RET mutations in MEN2 patients are related to the two main functionnal domains in the RET protein, the extracellular ligand binding domain (MEN2A and FMTC) and the intracellular catalytic domain (MEN2A, MEN2B and FMTC). Genotype-phenotype correlations have been established but must be used carefully in clinical practice. RET mutation analysis is now available for patients and prophylactic thyroidectomy in gene-carriers could be the most reliable way to cure the patients. Mechanisms of tumourigenesis induced by MEN2-related RET germline mutations have been analysed by in vitro studies and the generation of transgenic mice which develop true bilateral MTC. Recent insights on MEN syndrome pathogenesis and related inherited endocrine disorders have a major clinical impact and fundamental studies are now in progress in order to identify all genetic events leading from a normal endocrine tissue towards a fully malignant phenotype.

Occurrence of MEN 2a in familial Hirschsprung's disease: a new indication for genetic testing of the RET proto-oncogene

PURPOSE

The association of the rare hereditary cancer syndrome, multiple endocrine neoplasia type 2a (MEN 2a) with Hirschsprung's disease, both linked to germline mutations in the RET proto-oncogene, has been reported recently. With the widespread availability of genetic screening for MEN 2a, it is necessary to define the indications for genetic testing of MEN 2a and population subgroups at high risk for inheriting the disease. The purpose of this study was to assess the prevalence of Hirschsprung's disease in MEN 2a and investigate the value of genetic analysis for MEN 2a in children with familial Hirschsprung's disease.

METHODS

The ethnically diverse study group consisted of unselected consecutive patients (n=426) at risk for hereditary medullary thyroid cancer (MTC) referred to a single laboratory for genetic testing. Analysis used genomic DNA and a polymerase chain reaction-based heteroduplex mutation detection strategy for exons 10, 11, 13, and 14 of the RET proto-oncogene followed by direct DNA sequencing. Significance of RET genotype-phenotype correlation was determined by Fisher's two-tailed Exact test and a 2 x 2 contingency table.

RESULTS

Thirty-six distinctly new MEN 2a kindreds were identified. Hirschsprung's disease cosegregated among siblings with MEN 2a in 15 patients from 6 of the 36 (17%) families. The extent of aganglionosis in the 15 patients ranged from midrectum to duodenum. Of the 15 patients with Hirschsprung's disease, 10 (six boys, four girls) underwent thyroidectomy for MTC (n=5) or C-cell hyperplasia (n = 5) at ages 2 to 47 years (mean, 15.6 years), and the remaining five patients died in childhood of complications related to the aganglionosis. In retrospect, Hirschsprung's disease was the presenting feature of MEN 2a in five of the six families rather than MTC or pheochromocytoma. In all six MEN 2a families expressing Hirschsprung's disease, the RET mutation predisposing to the combined phenotype occurred in exon 10 at codons 609 (n=2), 618 (n=3), or 620 (n = 1). By contrast, the MEN 2a with Hirschsprung's phenotype was not found in any of the 22 families with a RETexon 11, 13, or 14 mutation (P=.0007).

CONCLUSIONS

The authors conclude that Hirschsprung's disease is a phenotypic marker for MEN 2a and possibly more common than originally appreciated. The expression of Hirschsprung's disease with MEN 2a may be uniquely linked to RETexon 10 mutations. The authors recommend that (1) patients affected with MEN 2a may be counseled regarding the potential risk of Hirschsprung's disease in offspring and (2) a family history of MTC be explored in children with familial Hirschsprung's disease and genetic screening for MEN 2a be considered.

A nationwide clinical survey of patients with multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma in Japan

MEN (multiple endocrine neoplasia) type 2 syndrome is an inherited disease characterized by medullary thyroid carcinoma, pheochromocytoma, hyperparathyroidism and/or developmental anomalies. Germ-line mutations of the RET proto-oncogene have recently been identified as the underlying cause of the syndrome. Accordingly, several investigators have advocated prophylactic total thyroidectomy for medullary thyroid carcinoma at an early age in MEN 2 gene carriers identified by DNA analysis. Before applying this strategy in Japan, the biological behavior of each category of tumor in MEN 2 syndrome, and medullary thyroid carcinoma in particular, should be well understood. We conducted a nationwide questionnaire survey to clarify the clinicopathological features of MEN 2 in Japan, obtaining data for 230 patients diagnosed as having MEN 2. They included 84 males and 146 females, with a median age of 37.5 years (range 5-83). Patients were categorized as 179 with MEN 2A, 17 with MEN 2B, 12 with familial medullary thyroid carcinoma and 22 'other'. Medullary thyroid carcinoma, pheochromocytoma and parathyroid lesions occurred in 224 (97%), 132 (57%) and 25 (11%) patients respectively. Twelve patients (5.2%) died of medullary thyroid carcinoma and 11 patients died of other or unknown causes. Of 163 patients for whom follow-up data were obtained, 82 (50%) experienced recurrences of medullary thyroid carcinoma, including symptomatic recurrent tumors in 24 patients and elevated calcitonin levels alone in 54. In the era of RET mutational analysis for screening relatives of patients with MEN 2, these data provide useful information about surgical management for patients with MEN 2 in Japan.

Phaeochromocytoma in Northern Ireland: a 21 year review

OBJECTIVE

To report our experience of 41 patients with phaeochromocytoma.

DESIGN

Retrospective study.

SETTING

Teaching hospital, United Kingdom.

SUBJECTS

Forty-one patients who presented with phaeochromocytoma 1970-1991.

INTERVENTIONS

Removal of tumour (n = 38).

MAIN OUTCOME MEASURES

Mortality, morbidity, and recurrence.

RESULTS

Thirty-four patients had sporadic tumours, five had the multiple endocrine neoplasia (MEN) type 2 syndrome, and two had non-MEN familial phaeochromocytoma. Thirty-six patients (88%) presented with symptoms of catecholamine excess, and 37 (90%) were hypertensive. The diagnosis was confirmed biochemically in 37. Tumours were located using computed tomography (n = 26), vascular studies (n = 11), and ultrasonography (n = 3). Thirty-eight patients had their tumours resected, of whom 10 (27%) developed complications. There were no postoperative deaths. Two patients were managed conservatively, and one died before diagnosis. Six patients developed recurrent tumours a mean of five years after the initial operation, and another patient had an inoperable tumour at initial diagnosis; four of these seven died from metastatic disease. Metaiodobenzylguanidine (MIBG) scans were positive in three of the patients who developed recurrences.

CONCLUSIONS

Patients with phaeochromocytoma can now be operated on safely but prolonged follow-up is essential.