Calcitonin Measurement to Detect Medullary Thyroid Carcinoma in Nodular Goiter: German Evidence-Based Consensus Recommendation

[30 years of prophylactic thyroidectomy for hereditary medullary thyroid cancer : A milestone in translational medicine]

Medullary thyroid cancer (MTC) is the most frequent manifestation of multiple endocrine neoplasia type 2 (MEN2) that determines the oncological outcome. Germline mutations in the rearranged during transfection (RET) protooncogene, a tumor suppressor gene on chromosome 10q11.2, were identified 30 years ago as the genetic basis of MEN2 and published in 1993 and 1994. These seminal findings gave rise to the concept of prophylactic thyroidectomy for asymptomatic gene mutation carriers based on a positive RET gene test, which has become the standard of care ever since. Clinical genetic investigations showed genotype-phenotype correlations with respect to the individual gene mutation regarding the penetrance and onset of MTC and to a lesser extent also with respect to the other components of MEN2, pheochromocytoma and primary hyperparathyroidism. From this a clinically relevant risk stratification could be derived. Initially, the optimal timing of prophylactic thyroidectomy was primarily based on the RET genotype alone, which was not sufficient for a precise age recommendation and subsequently required additional consideration of calcitonin serum levels for fine tuning. Calcitonin levels first show the risk of lymph node metastasis when they exceed the upper normal limit of the assay independent of carrier age and RET mutation. Routine calcitonin screening of patients with nodular thyroid disease, screening of families on identification of MEN2 index patients, and pre-emptive thyroidectomy in carriers of gene mutations with normal calcitonin levels have led to the fact that nowadays, 30 years after the first description of the gene mutations causing the disease, the life-threatening hereditary MTC has become curable: a shining example for the success of translational transnational medical research for the benefit of patients.

Preclinical Evaluation of Minigastrin Analogs and Proof-of-Concept [68Ga]Ga-DOTA-CCK-66 PET/CT in 2 Patients with Medullary Thyroid Cancer

Because of the need for radiolabeled theranostics for the detection and treatment of medullary thyroid cancer (MTC), and the yet unresolved stability issues of minigastrin analogs targeting the cholecystokinin-2 receptor (CCK-2R), our aim was to address in vivo stability, our motivation being to develop and evaluate DOTA-CCK-66 (DOTA-γ-glu-PEG3-Trp-(N-Me)Nle-Asp-1-Nal-NH2, PEG: polyethylene glycol) and DOTA-CCK-66.2 (DOTA-glu-PEG3-Trp-(N-Me)Nle-Asp-1-Nal-NH2), both derived from DOTA-MGS5 (DOTA-glu-Ala-Tyr-Gly-Trp-(N-Me)Nle-Asp-1-Nal-NH2), and clinically translate [68Ga]Ga-DOTA-CCK-66. Methods: 64Cu and 67Ga labeling of DOTA-CCK-66, DOTA-CCK-66.2, and DOTA-MGS5 was performed at 90°C within 15 min (1.0 M NaOAc buffer, pH 5.5, and 2.5 M 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer, respectively). 177Lu labeling of these 3 compounds was performed at 90°C within 15 min (1.0 M NaOAc buffer, pH 5.5, 0.1 M sodium ascorbate). CCK-2R affinity of natGa/natCu/natLu-labeled DOTA-CCK-66, DOTA-CCK-66.2, and DOTA-MGS5 was examined on AR42J cells. The in vivo stability of 177Lu-labeled DOTA-CCK-66 and DOTA-MGS5 was examined at 30 min after injection in CB17-SCID mice. Biodistribution studies at 1 h ([67Ga]Ga-DOTA-CCK-66) and 24 h ([177Lu]Lu-DOTA-CCK-66/DOTA-MGS5) after injection were performed on AR42J tumor-bearing CB17-SCID mice. In a translation to the human setting, [68Ga]Ga-DOTA-CCK-66 was administered and whole-body PET/CT was acquired at 120 min after injection in 2 MTC patients. Results: Irrespective of the metal or radiometal used (copper, gallium, lutetium), high CCK-2R affinity (half-maximal inhibitory concentration, 3.6-6.0 nM) and favorable lipophilicity were determined. In vivo, increased numbers of intact peptide were found for [177Lu]Lu-DOTA-CCK-66 compared with [177Lu]Lu-DOTA-MGS5 in murine urine (23.7% ± 9.2% vs. 77.8% ± 2.3%). Overall tumor-to-background ratios were similar for both 177Lu-labeled analogs. [67Ga]Ga-DOTA-CCK-66 exhibited accumulation (percentage injected dose per gram) that was high in tumor (19.4 ± 3.5) and low in off-target areas (blood, 0.61 ± 0.07; liver, 0.31 ± 0.02; pancreas, 0.23 ± 0.07; stomach, 1.81 ± 0.19; kidney, 2.51 ± 0.49) at 1 h after injection. PET/CT examination in 2 MTC patients applying [68Ga]Ga-DOTA-CCK-66 confirmed multiple metastases. Conclusion: Because of the high in vivo stability and favorable overall preclinical performance of [nat/67Ga]Ga-/[nat/177Lu]Lu-DOTA-CCK-66, a proof-of-concept clinical investigation of [68Ga]Ga-DOTA-CCK-66 was completed. As several lesions could be identified and excellent biodistribution patterns were observed, further patient studies applying [68Ga]Ga- and [177Lu]Lu-DOTA-CCK-66 are warranted.

Update on Calcitonin Screening for Medullary Thyroid Carcinoma and the Results of a Retrospective Analysis of 12,984 Patients with Thyroid Nodules

BACKGROUND

We provide an update on calcitonin (Ctn) screening for the early detection of medullary thyroid carcinoma (MTC) and present the results of a large single-center analysis evaluating sex-specific cut-off-levels and long-term courses.

METHODS

A total of 12,984 consecutive adult patients (20.1% male and 79.9% female) with thyroid nodules who had undergone routine Ctn measurement were retrospectively analyzed. Patients with confirmed suspicious Ctn values were referred for surgery.

RESULTS

Ctn measurements were elevated in 207 (1.6%) patients, with values below twice the sex-specific reference limit in 82% of these cases. Further clarification was possible in 124/207 cases, of which MTC could be ruled out in 108 cases. Histopathological assessment confirmed MTC in 16/12,984 patients.

CONCLUSIONS

Our extrapolated MTC prevalence of 0.14% is significantly lower than that described in early international screening studies. The stimulation test can usually be dispensable when using a decision-making concept based on sex-specific basal Ctn cut-off values. Ctn screening is recommended even in patients with very small thyroid nodules. High quality standards in pre-analytics, laboratory measurements, and the interpretation of data must be ensured, as well as close interdisciplinary cooperation between medical disciplines.

Basal and pentagastrin-stimulated calcitonin cut-off values in diagnosis of preoperative medullary thyroid cancer

Background/aim

Medullary thyroid cancer (MTC) originates from parafollicular cells (C cell) and produces calcitonin (CT). Basal serum CT was used in the diagnosis and treatment of MTC. If basal CT level is 100 pg/mL or higher, it is likely to have MTC, but if basal CT level is below 10 pg/mL, the probability of developing thyroid disease is low. In cases with basal CT level between 10–100 pg/mL, pentagastrin-stimulated (PS) CT level is studied to evaluate MTC and C cell hyperplasia (CHH). This study aimed to determine cut-off value for basal and PS peak CT level for diagnosis of MTC.

Materials and methods

We retrospectively reviewed files of patients presented to endocrine outpatient clinic of Ege University, Medicine School, between 2010 and 2019; 176 patients with basal CT level of 10–100 pg/mL and patients with PS test were included to the study.

Results

The receiver operating characteristic curve (ROC) analysis was used to determine cut-off value for basal CT that can discriminate cases with MTC and those with nodular goiter. Cut-off value for basal CT was calculated as 46.5 pg/mL (specificity; 100 %, sensitivity; 74 %). In the ROC analysis for peak PS CT, cut-off value was calculated as 285 pg/mL (specificity:100 %; sensitivity:82 %). When peak CT level was > 290 pg/mL in PS test, both specificity and sensitivity for MTC were determined as 100 %. The PS peak CT level > 285 pg/mL was significant for MTC diagnosis while range of 117–274 pg/mL was significant for CHH.

Conclusion

In this study, cut-off value was calculated as 46.5 pg/mL for basal CT, whereas 285 pg/mL for PS peak CT in the diagnosis of preoperative MTC.

[Thyroid nodules: The Guidelines of the American Thyroid Association from a European Perspective]

In Germany and in other regions with former iodine deficiency, thyroid nodules and nodular goiter are still much more frequent than in the U.S.A. The American Thyroid Association (ATA) has published 2015 revised guidelines for patients with thyroid nodules and differentiated thyroid cancer. For evaluation of suspected thyroid nodules the authors describe high, intermediate, low and very low suspicion pattern and recommend further fine needle aspiration cytology, depending on the pattern and the size of the nodule. The high suspicion pattern includes irregular margins of the nodule, which may be an important criterion for malignancy of solitary nodules. In nodular goiters with multiple nodules grown together and without clear margins, frequently observed in former iodine deficiency regions, irregular margins may not be a significant criterion for malignancy. Another pattern, hypoechogenicity, which is frequently seen in benign nodules in former iodine deficiency areas, is also not a clear criterion for malignancy. Only strong hypoechogenicity may indicate malignancy. Another difference relates to the recommendation of scintigraphy that according to the guideline is restricted to patients with decreased TSH. In regions with former iodine deficiency, it has been demonstrated that thyroid autonomy may be present even if TSH is in the lower normal range. Therefore, in Germany scintigraphy is recommended for preoperative evaluation of all patients with thyroid nodules or nodular goiter.

[Medullary thyroid carcinoma and multiple endocrine neoplasia type 2]

Medullary thyroid carcinoma (MTC) is a rare malignancy and compromises only 3 % of all thyroid carcinomas. MTC cells secret calcitonin, which serves as a sensitive tumor marker for screening and follow-up of MTC. Calcitonin screening in patients with nodular goiter allows for early diagnosis of MTC and surgical curative treatment. In 25 % of patients MTC occurs as an integral part of multiple endocrine neoplasia type 2 (MEN2), an autosomal dominant inherited tumor syndrome. It is caused by germline mutations in the RET protooncogene. In gene carriers early diagnosis and treatment through prophylactic thyroidectomy is possible. MTC is a slowly growing tumor with a good prognosis and 5 and 10 year survival rates up to 80 and 60 %. In the follow-up a dynamic risk stratification allows for a personalized disease management. In symptomatic and progressive metastasizing MTC tyrosine kinase inhibitors are an effective therapy.

Sentinel lymph node biopsy in medullary thyroid microcarcinomas

The aim of this prospective study was to analyze accuracy of sentinel lymph node biopsy with methylene blue dye for intraoperative detection of lateral metastases in clinically N0M0 medullary microcarcinomas with calcitonin <1,000 pg/mL and selection of true-positive patients for one-time therapeutic lateral dissection. In addition to total thyroidectomy and central neck dissection, all patients had bilateral sentinel biopsy of jugulo-carotid regions after methylene blue injection to decide upon necessity for lateral dissection. If sentinels were benign on frozen section, additional non-sentinels were extirpated, with no further lateral dissection. If sentinels were malignant, one-time lateral dissection was performed. 20 patients were included in this study. Hereditary disease form was observed in 3/20 (15%) of patients with RET proto-oncogene mutation C634F; remaining 17/20 (85%) were negative for germline mutations. There were no allergic reactions to methylene blue and identification rate of sentinels was 100%. In total, 2/20 (10%) cN0 patients had lymphonodal metastases, thus were reclassified as pN1b. Remaining 18/20 (90%) were classified pN0 based on standard pathohistology. Frozen section findings on sentinels were 100% match with standard pathohistology, and there were no skip metastases in lateral compartments. Sensitivity, specificity and accuracy of sentinel biopsy method with methylene dye and frozen section were 100%. Dzodic's sentinel lymph node biopsy method can be used for intraoperative assessment of lateral compartments and optimization of initial surgery of medullary microcarcinomas with calcitonin <1,000 pg/mL. This way, cN0 patients with sentinel metastases can receive one-time lateral dissection, and those without benefit from less extensive surgery.

Calcitonin concentrations in patients with chronic kidney disease on hemodialysis in reference to parathyroidectomy

Objective

Calcitonin is considered to be a biomarker of medullary thyroid carcinoma and C-cell hyperplasia, but calcitonin can also be elevated in about 30% of the patients with end-stage kidney disease. We reported preoperative calcitonin serum levels in 31 patients on hemodialysis before parathyroid surgery, evaluate influencing factors on calcitonin levels and determine postoperative calcitonin levels after parathyroid surgery.

Results

Median preoperative serum calcitonin was 8 pg/ml (range 2 to 165 pg/ml), serum calcitonin concentration declined postoperatively to 3 pg/ml (range 1 to 192 pg/ml). There was a strong positive correlation between pre- and postoperative serum calcitonin levels (r = 0.92; p > 0.01). Elevated preoperative serum calcitonin concentrations (more than 10 pg/ml) were found in 14 out of 32 dialysis-dependent patients (44%). Preoperative calcitonin levels of male patients were significantly higher than female patients. Hypercalcitoninemia showed a positive correlation to body mass index (p < 0.01). We found no correlation between preoperative calcitonin levels and patients’ age, duration of hemodialysis dependency, cinacalcet medication or preoperative concentrations of parathyroid hormone, creatinine and calcium. Basal calcitonin levels higher than 10 pg/ml are common in patients on dialysis. Male gender and morbid obesity are risk factors for hypercalcitoninemia. Calcitonin concentration decreases after parathyroid operation.

Secondary and tertiary preventions of thyroid disease

INTRODUCTION

Secondary and tertiary preventions are concerned with the recognition of the disease process in a very early stage and delay in progression to complete disease and minimization of complications and the impact of illness.

METHODS

All articles related to secondary and tertiary prevention of thyroid diseases were reviewed. Using related key words, articles published between 2001 and 2015 were evaluated, categorized, and analyzed.

RESULTS

In secondary prevention, congenital hypothyroidism and subclinical hypo and hyperthyroidism are equally important. Routine screening of patients with multinodular goiter by either ultrasonography or calcitonin is a controversial issue, while calcitonin assessments in medullary cancer and RET in family members are recommended. Screening of thyroid disease in pregnancy is limited to those with risk factors. Views regarding the importance of thyroid autoimmunity in secondary prevention are also presented. In tertiary prevention, prescribing excessive doses of levothyroxine, in the elderly in particular and appropriate care of all patients to avoid progression and complications are the key issues.

CONCLUSION

Optimization of management of thyroid diseases requires timely screening, prevention of progression to more sever disease, optimal medical care, and avoidance of iatrogenic conditions.

United States and European Multicenter Prospective Study for the Analytical Performance and Clinical Validation of a Novel Sensitive Fully Automated Immunoassay for Calcitonin

BACKGROUND

The objective of this study is the validation and proof of clinical relevance of a novel electrochemiluminescence immunoassay (ECLIA) for the determination of serum calcitonin (CT) in patients with medullary thyroid carcinoma (MTC) and in different diseases of the thyroid and of calcium homeostasis.

METHODS

This was a multicenter prospective study on basal serum CT concentrations performed in 9 US and European referral institutions. In addition, stimulated CT concentrations were measured in 50 healthy volunteers after intravenous calcium administration (2.5 mg/kg bodyweight).

RESULTS

In total, 1929 patients and healthy controls were included. Limits of blank, detection, and quantification for the ECLIA were 0.3, 0.5, and 1 ng/L, respectively. Highest intra- and interassay coefficients of variation were 7.4% (CT concentration, 0.8 ng/L) and 7.0% (1.1 ng/L), respectively. Medians (interval) of serum CT concentrations in 783 healthy controls were 0.8 ng/L (&lt;0.5–12.7) and 3 ng/L (&lt;0.5–18) for females and males, respectively (97.5th percentile, 6.8 and 11.6 ng/L, respectively). Diagnostic sensitivity and specificity were 100%/97.1% and 96.2%/96.4%, for female/males, respectively. Patients (male/female) with primary hyperparathyroidism, renal failure, and neuroendocrine tumors showed CT concentrations &gt;97.5th percentile in 33%/4.7%, 18.5%/10%, and 8.3%/12%, females/males, respectively. Peak serum CT concentrations were reached 2 min after calcium administration (161.7 and 111.8 ng/L in males and females, respectively; P &lt; 0.001).

CONCLUSIONS

Excellent analytical performance, low interindividual variability, and low impact of confounders for increased CT concentrations in non-MTC patients indicate that the investigated assay has appropriate clinical utility. Calcium-stimulated CT results suggest good test applicability owing to low interindividual variability.

Prevalence of thyroid disorders in elderly people in Germany. A screening study in a country with endemic goitre

AIM

In a screening study on people of working age the prevalence of morphological thyroid disorders was 33.1 %. It is not known precisely whether this further increases after retirement. The present study aimed to establish whether the increase in the prevalence of morphological and functional thyroid disorders continues beyond working age in elderly citizens.

METHODS

223 participants were recruited in an institute for geriatric rehabilitative medicine. All patients were screened by thyroid ultrasound, measurement of serum levels of thyroid hormones and thyroid related autoantibodies as well as measurement of urinary iodine excretion.

RESULTS

The median thyroid volume was 17 ml (range 4-41 ml) in men and 16 ml (range 0.4-73 ml) in women. 27/59 (46 %) of the men (median age [range]: 77 [58-87] years) and 85/139 (61 %) of the women (median age [range]: 77 [52-97] years), or a total of 112/198 (57 %) residents, showed morphological thyroid abnormalities. There was no clear increase with age. 85 % of the participants without a history of thyroid treatment were euthyroid. 12 % showed a subclinical hyperthyroidism whereas 1 % showed a biochemically manifest hyperthyroidism. 2 % were biochemically hypothyroid. Tg-antibodies was elevated in 10 (5 %) and TPO-antibodies in 18 (9 %) of the patients. Median iodine excretion was 129 µg/l. 41.5 % of the patients showed iodine excretion values below 100 µg/l whereas only 7 % of the patients showed a severe iodine deficiency with an excretion below 50 µg/l.

CONCLUSION

Compared to a previously described population of working age, the prevalence of morphological thyroid disorders does not further increase above the age of 65; thyroid function abnormalities in this iodine sufficient screening population were relatively rare.

Medullary Thyroid Carcinoma

Medullary thyroid carcinoma (MTC) is subdivided into sporadic (75%) and hereditary (25%) forms. Several germline mutations in the RET proto-oncogene are the source of distinct clinical phenotypes in hereditary MTC including familial MTC (FMTC) and multiple endocrine neoplasia 2A (MEN 2A) and 2B (MEN 2B). The higher the penetrance of the MEN 2 phenotype the earlier the progression of MTC which forms the basis for the currently recommended codon-related concept of prophylactic thyroidectomy. In patients with sporadic MTC, routine calcitonin (CT) measurement in nodular goiter patients has been shown to reduce the frequency of advanced tumor stages. Patients with CT levels over 100 pg/ml after pentagastrin stimulation are recommended for total thyroidectomy. In patients with unexpected sporadic MTC after histological examination, completion thyroidectomy is currently only recommended when CT levels remain elevated. The extent of lymph node dissection in patients with MTC is controversial. However, with respect to lymphonodal micrometastases, systematic compartment-oriented microdissection has been shown to reduce the frequency of lymphonodal recurrence. On the other hand, to avoid unnecessary lymph node dissection, a more individualized concept is required in the future. New chemotherapeutic agents (tyrosine kinase inhibitors), therapeutic nuclids (90Yttrium-labeled octreotide), and chemoembolization of liver metastases are currently the most promising therapeutical concepts in patients with distant metastases.

Surgical cure rates of sporadic medullary thyroid cancer in the era of calcitonin screening

OBJECTIVE

Time trends of the extent of disease at first diagnosis and biochemical cure remain ill-defined for sporadic medullary thyroid cancer (MTC). This investigation aimed to delineate time trends and biochemical cure rates for sporadic MTC.

DESIGN

This was an observational study of consecutive patients operated on for sporadic MTC between 1995 and 2015.

METHODS

Time trends of clinical and histopathological variables indicative of the extent of disease and biochemical cure were calculated for 600 patients with sporadic MTC, 322 of whom had initial neck surgery and 278 of whom had neck reoperation at a tertiary surgical center in Germany.

RESULTS

From 1995-2000 to 2011-2015, significant declines (all P<0.001) were noted in the percentage of node-positive tumors (from 73 to 49%), mediastinal lymph node metastasis (from 21 to 6%) and distant metastasis (from 23 to 6%). These changes were paralleled by significant increases (all P<0.001) in mean patient age (from 49.1 to 57.3years) and the percentage of MTC ≤10mm (from 19 to 39%) and biochemical cure (from 28 to 62%). When only patients with primary tumors >10mm were considered, the decreasing percentage of mediastinal lymph node metastasis and distant metastasis, and rising mean patient age and biochemical cure rates remained statistically significant.

CONCLUSIONS

Significant reductions in the extent of the disease and improved biochemical cure rates pointed toward increasing therapeutic control of sporadic MTC. The independent contribution of routine calcitonin screening to these time-dependent changes warrants more research.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS, AMERICAN COLLEGE OF ENDOCRINOLOGY, AND ASSOCIAZIONE MEDICI ENDOCRINOLOGI MEDICAL GUIDELINES FOR CLINICAL PRACTICE FOR THE DIAGNOSIS AND MANAGEMENT OF THYROID NODULES--2016 UPDATE

Thyroid nodules are detected in up to 50 to 60% of healthy subjects. Most nodules do not cause clinically significant symptoms, and as a result, the main challenge in their management is to rule out malignancy, with ultrasonography (US) and fine-needle aspiration (FNA) biopsy serving as diagnostic cornerstones. The key issues discussed in these guidelines are as follows: (1) US-based categorization of the malignancy risk and indications for US-guided FNA (henceforth, FNA), (2) cytologic classification of FNA samples, (3) the roles of immunocytochemistry and molecular testing applied to thyroid FNA, (4) therapeutic options, and (5) follow-up strategy. Thyroid nodule management during pregnancy and in children are also addressed. On the basis of US features, thyroid nodules may be categorized into 3 groups: low-, intermediate-and high-malignancy risk. FNA should be considered for nodules ≤10 mm diameter only when suspicious US signs are present, while nodules ≤5 mm should be monitored rather than biopsied. A classification scheme of 5 categories (nondiagnostic, benign, indeterminate, suspicious for malignancy, or malignant) is recommended for the cytologic report. Indeterminate lesions are further subdivided into 2 subclasses to more accurately stratify the risk of malignancy. At present, no single cytochemical or genetic marker can definitely rule out malignancy in indeterminate nodules. Nevertheless, these tools should be considered together with clinical data, US signs, elastographic pattern, or results of other imaging techniques to improve the management of these lesions. Most thyroid nodules do not require any treatment, and levothyroxine (LT4) suppressive therapy is not recommended. Percutaneous ethanol injection (PEI) should be the first-line treatment option for relapsing, benign cystic lesions, while US-guided thermal ablation treatments may be considered for solid or mixed symptomatic benign thyroid nodules. Surgery remains the treatment of choice for malignant or suspicious nodules. The present document updates previous guidelines released in 2006 and 2010 by the American Association of Clinical Endocrinologists (AACE), American College of Endocrinology (ACE) and Associazione Medici Endocrinologi (AME).

Surgical Treatment of Medullary Thyroid Cancer

Medullary thyroid cancer (MTC) can vary in tumor biology and progression. The most important indicator of distant metastases, determining clinical outcome, is lymph node metastasis to the neck and mediastinum. Surgical cure is within reach in node-negative tumors or node-positive tumors with fewer than 10 lymph node metastases. From a surgical point of view, compartment-oriented lymph node dissection, clearing gross, and occult metastases are important for locoregional tumor control. The discovery of missense germline mutations in the RET proto-oncogene and the close genotype-phenotype correlation in hereditary MTC promoted the worldwide breakthrough of prophylactic thyroidectomy. The best approach to hereditary MTC affords the DNA-based/biochemical concept, which is geared at limiting prophylactic surgery to total thyroidectomy at minimal surgical morbidity before the tumor can spread beyond the thyroid capsule. To improve outcome, routine calcitonin screening in nodular thyroid disease and DNA-based screening of the offspring in RET families are effective interventions.

Calcitonin as Biomarker for the Medullary Thyroid Carcinoma

Calcitonin (CTN) is a polypeptide hormone consisting of 32 amino acids with a disulfide bridge between position 1 and 7 that is mainly produced by the C-cells of thyroid gland. The measurement of CTN concentrations in blood reflects C-cell activity and is performed in general by immunoassay methods. However, there are analytical, physiological, pharmacological, and pathological factors that can influence results of serum CTN values. Due to the influence of these factors, there is a high variability in assay-dependent cutoffs used to discriminate between MTC, C-cell hyperplasia (CCH), and the absence of the pathological impairment of C-cells. There is a lot of evidence that the measurement of serum CTN concentrations in patients with thyroid nodules can lead to an earlier diagnosis of MTC or CCH than the exclusive use of imaging procedures and/or fine-needle aspiration cytology. Basal CTN concentrations higher than 60-100 pg/mL are highly indicative for the diagnosis MTC. In the range between cutoff and 60 pg/mL CTN, both MTC and HCC may be a relevant diagnosis. PCT and CTN appear to have a comparable diagnostic capability to diagnose MTCs. However, "positive" PCT values of more than 50 pg/mL may be reached also in subclinical infections and will lead, therefore, to an overdiagnosis of the tumor. Pentagastrin- or calcium-stimulated serum CTN concentrations higher than cutoff values might improve diagnostics of MTC, but the non-availability of the first and the lacking of relevant cutoff values for the second tool favors the use of only basal values currently.

Diagnóstico, tratamento e seguimento do carcinoma medular de tireoide: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia

Introdução O carcinoma medular de tireoide (CMT) origina-se das células parafoliculares da tireoide e corresponde a 3-4% das neoplasias malignas da glândula. Aproximadamente 25% dos casos de CMT são hereditários e decorrentes de mutações ativadoras no proto-oncogene RET (REarranged during Transfection). O CMT é uma neoplasia de curso indolente, com taxas de sobrevida dependentes do estádio tumoral ao diagnóstico. Este artigo descreve diretrizes baseadas em evidências clínicas para o diagnóstico, tratamento e seguimento do CMT. Objetivo O presente consenso, elaborado por especialistas brasileiros e patrocinado pelo Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia, visa abordar o diagnóstico, tratamento e seguimento dos pacientes com CMT, de acordo com as evidências mais recentes da literatura. Materiais e métodos: Após estruturação das questões clínicas, foi realizada busca das evidências disponíveis na literatura, inicialmente na base de dados do MedLine-PubMed e posteriormente nas bases Embase e SciELO – Lilacs. A força das evidências, avaliada pelo sistema de classificação de Oxford, foi estabelecida a partir do desenho de estudo utilizado, considerando-se a melhor evidência disponível para cada questão. Resultados Foram definidas 11 questões sobre o diagnóstico, 8 sobre o tratamento cirúrgico e 13 questões abordando o seguimento do CMT, totalizando 32 recomendações. Como um todo, o artigo aborda o diagnóstico clínico e molecular, o tratamento cirúrgico inicial, o manejo pós-operatório e as opções terapêuticas para a doença metastática. Conclusões O diagnóstico de CMT deve ser suspeitado na presença de nódulo tireoidiano e história familiar de CMT e/ou associação com feocromocitoma, hiperparatireoidismo e/ou fenótipo sindrômico característico, como ganglioneuromatose e habitus marfanoides. A punção aspirativa por agulha fina do nódulo, a dosagem de calcitonina sérica e o exame anatomopatológico podem contribuir na confirmação do diagnóstico. A cirurgia é o único tratamento que oferece a possibilidade de cura. As opções de tratamento da doença metastática ainda são limitadas e restritas ao controle da doença. Uma avaliação pós-cirúrgica criteriosa para a identificação de doença residual ou recorrente é fundamental para definir o seguimento e a conduta terapêutica subsequente.

Malignancy rate of thyroid nodules defined as follicular lesion of undetermined significance and atypia of undetermined significance in thyroid cytopathology and its relation with ultrasonographic features

Fine-needle aspiration biopsy (FNAB) has been widely accepted as the most accurate, safe, and cost-effective method for evaluation of thyroid nodules. The most challenging category in FNAB is atypia of undetermined significance (AUS) and follicular lesion of undetermined significance (FLUS). The Bethesda system (BS) recommends repeat FNAB in that category due to its low risk of malignancy. In our study, we aimed to investigate the malignancy rate of thyroid nodules of AUS and FLUS and whether there were different malignancy rates among the different patterns in this category, and to evaluate the presence of biochemical, clinical, and echographic features possibly predictive of malignancy related to AUS and FLUS. Data of 268 patients operated for AUS and FLUS cytology were screened retrospectively. Ultrasonographic features and thyroid function tests, thyroid antibodies, scintigraphy, and histopathological results were evaluated. Of the 268 patients' results, 276 nodules are evaluated. Malignancy rates were 24.3 % in the AUS group, 19.8 % in the FLUS group, and 22.8 % in both groups. In the evaluation of all nodules, the predictive features of malignancy are hypoechogenicity and peripheral vascularization of the nodule. We determined that the malignancy rates in these nodules are higher than that in the literature rate. This high ratio may be due to the fact that we studied only patients who underwent surgery. The ultrasonographic features alone may be insufficient to predict the malignancy; therefore, all the clinical and ultrasonographic features must be considered in the evaluation of the thyroid nodules. In addition, we think that the recommended management of repeat FNAB in these groups must be reconsidered with the clinical and ultrasonographic features.

Interest of sentinel node biopsy in apparently intrathyroidal medullary thyroid cancer: a pilot study

PURPOSE

Initial surgery for medullary thyroid cancer (MTC) with no evidence of lymph node involvement in neck compartments consists of total thyroidectomy and prophylactic central neck dissection. This study evaluated the reliability of a radiotracer technique for the intraoperative detection of sentinel lymph nodes (SLNs) in lateral compartments in patients with early MTC.

METHODS

Patients with limited (cT1 N0) MTC entered the study (2009-2012). A 0.1-0.3 ml suspension of macrocolloidal technetium-99-labeled human albumin was injected (under echo-guide) in the tumor 5 h before surgery. Preoperative lymphoscintigraphy confirmed the identification of SLNs in the lateral neck. The operation consisted of total thyroidectomy and central neck dissection, and a hand-held gamma-probe (Neoprobe) guide was used to remove the SLNs from the lateral neck.

RESULTS

Four patients were recruited. The tracer always indicated a SLN. Pathology reports indicated micrometastases from MTC in SLN in three patients. At a mean follow-up of 30.5 months, all patients were biochemically cured. The technique we describe to detect and remove neck SLN from MTC seemed to be very accurate. It always showed the SLNs (usually two) in the lateral compartments. Micrometastases were detected in three of four patients, allowing their correct staging.

CONCLUSIONS

The method described here for the detection of SLNs in early MTC seems effective and reliable and can be used for a more precise N staging of the patients. It could play a role, alone or combined with other techniques, in driving the extent of prophylactic neck dissection or other potential applications.

Serum calcitonin may falsely estimate tumor burden in chronic hypercalcemia: a case of prostatic and multiple bone metastases from medullary thyroid cancer

BACKGROUND

Medullary thyroid cancer (MTC) is a calcitonin (Ct)-secreting tumor of the parafollicular or C cells of the thyroid gland. Higher serum Ct levels are associated with larger tumor size, distant metastases, and prognosis. We report herein a case of prostate and multiple bone metastases of nonfamilial MTC with mildly elevated Ct levels.

PATIENT FINDINGS

A 73-year-old man who was found to have a 2.5 cm MTC in the left thyroid lobe with cervical lymph node metastases presented with confused mental status because of severe hypercalcemia (albumin-modified serum calcium concentration 15.2 mg/dL) associated with multiple bone metastases. Prostate biopsy was performed because the patient had frequent urination with mildly elevated serum prostate-specific antigen (5.297 ng/mL). Histologically, the prostate was diagnosed as MTC metastasis, forming a tissue architecture closely resembling the previously diagnosed MTC, and the cells were positive for Ct, carcinoembryonic antigen, and thyroid transcription factor 1. Although the patient had multiple MTC metastases, basal and calcium-stimulated serum Ct levels were not significantly elevated, measuring 22.7 pg/mL (normal <10 pg/mL) and 22.1 pg/mL, respectively.

CONCLUSIONS

A chronic hypercalcemic state may exhaust Ct reserves and diminish the Ct response to an acute intravenous calcium injection. Therefore, the Ct level of a patient in a hypercalcemic state should be carefully interpreted. To our knowledge, this is the first reported case in the literature in which serum Ct levels were not significantly increased when associated with hypercalcemia, and an MTC metastasis to the prostate.

Investigation of factors potentially influencing calcitonin levels in the screening and follow-up for medullary thyroid carcinoma: a cautionary note

BACKGROUND

The malignant transformation of thyroid C cells is associated with an increase in human calcitonin (hCT), which can thus be helpful in the early diagnosis of medullary thyroid carcinoma (MTC). For this reason, hCT levels should be determined in all patients with nodular goitre. Hashimoto's thyroiditis, nodular goitre and proton pump inhibitor (PPI) therapy are factors reported to influence basal serum hCT concentrations. The diagnostic role of mildly to moderately increased hCT levels is thus a matter of debate. In this study, we attempt to clarify the role of the aforementioned factors.

METHODS

From 2008 to 2009, we collected data from 493 patients who were divided into five groups. We assessed whether there were significant differences in hCT levels between patients with Hashimoto's thyroiditis, patients with nodular goitre, patients with PPI therapy, and healthy control subjects. In addition, we investigated whether a delayed analysis of blood samples has an effect on serum hCT concentrations.

RESULTS

Immunoradiometric assays (Calcitonin IRMA magnum, MEDIPAN) revealed that the time of analysis did not play a role when low levels were measured. Delayed analysis, however, carried the risk of false low results when serum hCT concentrations were elevated. Men had significantly higher serum hCT levels than women. The serum hCT concentrations of patients with Hashimoto's thyroiditis and nodular goitre were not significantly different from those of control subjects. Likewise, PPI therapy did not lead to a significant increase in serum hCT concentrations regardless of the presence or absence of nodular goitre.

CONCLUSIONS

Increases in serum hCT levels are not necessarily attributable to Hashimoto's thyroiditis, nodular goitre or the regular use of PPIs and always require further diagnostic attention.

Multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma: an update

CONTEXT

Over the last decade, our knowledge of the multiple endocrine neoplasia (MEN) type 2 syndromes MEN2A and MEN2B and familial medullary thyroid carcinoma (FMTC) has expanded greatly. In this manuscript, we summarize how recent discoveries have enhanced our understanding of the molecular basis of these diseases and led to improvements in the diagnosis and management of affected patients.

EVIDENCE ACQUISITION

We reviewed the English literature through PubMed from 2000 to the present, using the search terms medullary thyroid carcinoma, multiple endocrine neoplasia type 2, familial medullary thyroid carcinoma, RET proto-oncogene, and calcitonin.

EVIDENCE SYNTHESIS

Over 70 RET mutations are known to cause MEN2A, MEN2B, or FMTC, and recent findings from studies of large kindreds with these syndromes have clouded the relationship between genotype and phenotype, primarily because of the varied clinical presentation of different families with the same RET mutation. This clinical variability has also confounded decisions about the timing of prophylactic thyroidectomy for MTC, the dominant endocrinopathy associated with these syndromes. A distinct advance has been the demonstration through phase II and phase III clinical trials that molecular targeted therapeutics are effective in the treatment of patients with locally advanced or metastatic MTC.

CONCLUSIONS

The effective management of patients with MEN2A, MEN2A, and FMTC depends on an understanding of the variable behavior of disease expression in patients with a specific RET mutation. Information gained from molecular testing, biochemical analysis, and clinical evaluation is important in providing effective management of patients with either early or advanced-stage MTC.

German Association of Endocrine Surgeons practice guideline for the surgical management of malignant thyroid tumors

INTRODUCTION

Over the past years, the incidence of thyroid cancer has surged not only in Germany but also in other countries of the Western hemisphere. This surge was first and foremost due to an increase of prognostically favorable ("low risk") papillary thyroid microcarcinomas, for which limited surgical procedures are often sufficient without loss of oncological benefit. These developments called for an update of the previous practice guideline to detail the surgical treatment options that are available for the various disease entities and tumor stages.

METHODS

The present German Association of Endocrine Surgeons practice guideline was developed on the basis of clinical evidence considering current national and international treatment recommendations through a formal expert consensus process in collaboration with the German Societies of General and Visceral Surgery, Endocrinology, Nuclear Medicine, Pathology, Radiooncology, Oncological Hematology, and a German thyroid cancer patient support organization.

RESULTS

The practice guideline for the surgical management of malignant thyroid tumors includes recommendations regarding preoperative workup; classification of locoregional nodes and terminology of surgical procedures; frequency, clinical, and histopathological features of occult and clinically apparent papillary, follicular, poorly differentiated, undifferentiated, and sporadic and hereditary medullary thyroid cancers, thyroid lymphoma and thyroid metastases from primaries outside the thyroid gland; extent of thyroidectomy; extent of lymph node dissection; aerodigestive tract resection; postoperative follow-up and surgery for recurrence and distant metastases.

CONCLUSION

These evidence-based recommendations for surgical therapy reflect various "treatment corridors" that are best discussed within multidisciplinary teams and the patient considering tumor type, stage, progression, and inherent surgical risk.

Prevalence and clinical spectrum of nonsecretory medullary thyroid carcinoma in a series of 839 patients with sporadic medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) is characterized by the synthesis and secretion of calcitonin (Ct). MTC without Ct secretion has been reported on rare occasions. The aim of this study was to analyze the prevalence and clinical spectrum of nonsecretory MTC in two tertiary centers that cared for 839 patients with sporadic MTC.

METHODS

Clinical, biochemical, histological, and immunohistological findings, and somatic RET mutations were analyzed, and long-term follow-up was documented.

RESULTS

Seven patients with nonsecretory MTC were identified among 839 patients with sporadic MTC; thus, the prevalence rate of nonsecretory MTC was 0.83%. In these seven patients, Ct and carcinoembryonic antigen (CEA) levels were normal when MTC was initially diagnosed in the patients, despite advanced tumor stage. Ct and CEA levels remained undetectable in four patients; recurrence was indicated in one patient after 10 years of follow-up by routine anatomic imaging and increased CEA levels, and Ct levels became slightly elevated during follow-up, despite massive tumor load, in the remaining two patients. The diagnosis of MTC was confirmed by positive immunohistochemistry for Ct, CEA, and chromogranin A. A high Ki67 proliferation index (PI) (three patients) and a high proportion of RET 918-mutated cells (four patients), as well as poorly differentiated histology, were associated with aggressive biological behavior of the MTC. The prognosis for nonsecretory MTC varied between long-term survival (12.5 years) and rapid progression leading to death within 1.75 years after diagnosis.

CONCLUSIONS

The prevalence of nonsecretory MTC was low (0.83% of patients with MTC). Diagnosis was often made at a clinically advanced tumor stage. The histological and immunohistological characteristics and the clinical course and prognosis of nonsecretory MTC are markedly heterogeneous. A high Ki-67 PI and a large proportion of cells with RET 918 mutations are associated with a poor prognosis.

Twenty years of experience with the preoperative diagnosis of medullary cancer in a moderately iodine-deficient region

Background. There is a current debate in the medical literature about plasma calcitonin screening in patients with nodular goiter (NG). We decided on analyzing our 20-year experience with patients in an iodine-deficient region (ID). Patients and Methods. 22,857 consecutive patients with NG underwent ultrasonography and aspiration cytology (FNAC). If FNAC raised suspicion of medullary cancer (MTC), the serum calcitonin was measured. Results. 4,601 patients underwent surgery; there were 23 patients among them who had MTC (0.1% prevalence). Significantly more MTC cases were diagnosed cytologically in the second decade than in the first: 11/12 and 6/11, respectively. The frozen section was of help in 2 cases out of 3. Two patients suffered from a 3-year delay in proper therapy, and reoperation was necessary in 1 case. FNAC raised the suspicion of MTC in 20 cases that were later histologically verified and did not present MTC. The diagnostic accuracy of FNAC in diagnosing MTC was 99.2%. Two false-positive serum calcitonin tests (one of them in a hemodialyzed patient) and one false-negative serum calcitonin test occurred in 40 cases. Conclusion. Regarding the low prevalence of MTC in ID regions, calcitonin screening of all NG patients does not only appear superfluously but may have more disadvantages than advantages.

Calcitonin screening in patients with thyroid nodules. Diagnostic value

AIM

The positive predictive value (PPV) of a slightly elevated basal calcitonin (CT) for the diagnosis of medullary thyroid cancer (MTC) is still under debate.

PATIENTS, METHODS

A total of 11270 patients with thyroid nodules underwent calcitonin screening. Patients with known elevation of CT, renal insufficiency, bacterial infection, alcohol abuse, proton-pump inhibitor therapy or autoimmune thyroid disease were excluded from further analysis. Serum CT was determined by the solid-phase, enzyme-labeled, two-site chemiluminescent immunoassay Immulite 2000. If possible, a pentagastrin test was done to differentiate cases of hypercalcitoninaemia.

RESULTS

Hypercalcitoninsemia was found in 32 patients. 20 patients underwent surgery. In 10 patients a MTC was found. The PPV of hypercalcitoninaemia for MTC was 31%. The PPV increased to 50% for those patients who underwent surgery (10/20). A subgroup of 26 patients presented with basal CT between 13 and 50 pg/ml, 14 of them underwent surgery, in 4 cases evidence of MTC was revealed. This resulted in a PPV of 15% (4/26), although the value increased to 28% when only surgically treated patients were considered (4/14).

CONCLUSION

Taking all clinical data into account, calcitonin screening has an acceptable PPV for medullary thyroid cancer in patients with thyroid nodules. Therefore, we recommend calcitonin screening in centers for thyroid disorders.

Euthyroid goiter with and without nodules--diagnosis and treatment

BACKGROUND

Thyroid enlargement and thyroid nodules are common in the general population. This review concerns their proper diagnostic assessment and treatment.

METHODS

We selectively reviewed the literature from 1990 to 2012 and evaluated original articles and reviews retrieved from the PubMed database, as well as the recommendations of the following specialty societies: the German Societies of Endocrinology and Nuclear Medicine (Deutsche Gesellschaft für Endokrinologie, Deutsche Gesellschaft für Nuklearmedizin), the German Working Group for Endocrine Surgery (Chirurgische Arbeitsgemeinschaft Endokrinologie, CAEK), the European Thyroid Association, and the American Thyroid Association.

RESULTS

There have been very few randomized trials concerning the diagnosis and treatment of goiter. Nodular goiter can be managed by watchful waiting, drug treatment (initially with levothyroxine and iodide), radioactive iodine therapy, or surgery.

CONCLUSION

Many patients with nodules need no treatment at all. Treatment is indicated, however, if the patient is symptomatic and/or has an autonomously functioning ("hot") nodule, or if cancer is suspected. Potentially cancerous nodules must be operated on. If euthyroid nodular goiter is to be treated with the main goal of size reduction, either surgery or radioactive iodine therapy can be used. Drug treatment is an option for small nodules or goiters, but iatrogenic hyperthyroidism must be avoided at all costs. The type of follow-up that is required depends on the chosen treatment.

Comparison of calcium and pentagastrin tests for the diagnosis and follow-up of medullary thyroid cancer

CONTEXT

The evaluation of basal calcitonin (bCT) and stimulated calcitonin (sCT) can be used for the diagnosis and follow-up of medullary thyroid cancer (MTC).

OBJECTIVE

The aim of this study was to evaluate the reliability of high-calcium (Ca) test and to identify gender-specific thresholds for MTC diagnosis.

PATIENTS

Patients with MTC in remission (n=24) or in persistence (n=18), RET gene mutations carriers (n=14), patients with nodular goiter (n=69), and healthy volunteers (n=16) were submitted to pentagastrin and Ca (25 mg/kg) tests.

RESULTS

In all groups, the levels of calcitonin (CT) stimulated by either pentagastrin or Ca were significantly correlated. The prevalence of both C-cell hyperplasia (CCH) and MTC in women and men paralleled the increasing basal and peak CT levels in a gender-specific manner. Receiver operating characteristic plot analyses showed that the best levels of bCT to separate normal and CCH cases from MTC patients were above 18.7 pg/ml in females and above 68 pg/ml in males. Furthermore, Ca sCT above 184 pg/ml in females and above 1620 pg/ml in males had the highest accuracy to distinguish normal and CCH cases from patients with MTC. At the C-cell immunohistochemical examination, Ca sCT below 50 pg/ml corresponded to a mean number of 30 cells per 10 fields, whereas higher sCT associated with a mean number of 400 cells per 10 fields, often displaying a diffuse and nodular distribution pattern.

CONCLUSIONS

High-dose Ca test is a potent and well-tolerated procedure that can be applied worldwide at a low cost. Reference ranges for Ca sCT levels in different groups of patients and CT thresholds to diagnose CCH/MTC have been identified.

Germline RET sequence variation I852M and occult medullary thyroid cancer: harmless polymorphism or causative mutation?

OBJECTIVE

Rearranged during transfection (RET) gene analysis, widely used to identify carriers at risk of medullary thyroid cancer (MTC), occasionally uncovers novel sequence 'variants of unknown clinical significance' including RET I852M. This study aimed to clarify whether RET I852M represents a harmless polymorphism or a pathogenic mutation.

DESIGN

Clinical investigation supported by functional characterization of I852M mutant cells in vitro.

PATIENTS AND MEASUREMENTS

Genotype-phenotype correlation including five kindreds from a three-generational Caucasian I852M RET family.

RESULTS

A node-negative occult MTC was found in the 64-year-old index patient who had increased basal and stimulated peak calcitonin levels of 190 and 13 307 ng/l, respectively. Her 4-year-old grandson had no histopathological evidence of C-cell disease although his serum calcitonin levels had increased within 5 months from 3·2 to 6·3 ng/l basally and from 17·2 to 24·5 ng/l after pentagastrin stimulation. His mother and two 11- and 1·5-year-old siblings, also carrying the gene, had normal basal and stimulated calcitonin levels and hence did not undergo surgery. Functional characterization of transfected NIH3T3 cells in vitro (cell proliferation rate; cell viability; anchorage-independent cell growth; cell migration; and invasion) indicated that I852M mutant cells have transforming and migratory activities similar to American Thyroid Association (ATA) class A V804M mutants. I852M mutants demonstrated a weaker proliferative potential than fast-proliferating ATA class C C634R mutants and revealed a weaker migratory activity compared with aggressively growing ATA class D A883F mutants.

CONCLUSIONS

I852M sequence variations represent genuine RET mutations, falling into ATA class A of weakly activating RET germline mutations.

Screening for medullary thyroid carcinoma with serum calcitonin measurements in patients with thyroid nodules in the United States and Canada

BACKGROUND

Medullary thyroid carcinoma (MTC) is a rare thyroid malignancy with the potential for aggressive behavior. Measurement of serum calcitonin (Ct) in the thyroid nodule population is the most sensitive way to detect occult MTC. An important and controversial question is whether all patients with thyroid nodules should undergo Ct measurements to detect occult MTC.

SUMMARY

The prevalence of MTC detected by performing surgery on unselected individuals with thyroid nodules with elevated serum Ct is 0.4%. The central role of pentagastrin (PG) stimulation for triaging patients with minimally elevated serum Ct to prevent unnecessary surgery is reviewed. Data concerning a large reservoir of medullary thyroid microcarcinomas are discussed.

CONCLUSION

Given the unavailability of PG in the United States and Canada, the available data argue against routine Ct measurements in all individuals with thyroid nodules in these countries because of the potential for unnecessary surgery and the uncertain benefit in diagnosing medullary microcarcinoma.

Simultaneous medullary and papillary thyroid cancer: a novel entity?

BACKGROUND

The causes underlying the phenomenon of simultaneous medullary (MTC) and papillary thyroid cancer (PTC) are unclear.

METHODS

This study of 26 patients with simultaneous MTC and PTC aimed at clarifying clinical and histopathologic characteristics and trends of this unusual condition among MTC and PTC patients who were operated on at a tertiary referral center in Germany.

RESULTS

A total of 26 patients revealed simultaneous MTC and PTC, yielding the following rates: 2.6% (26 patients) among all 1019 PTC patients, 2.6% (6 patients) among all 235 hereditary MTC patients, 4.1% (20 patients) among all 492 sporadic MTC patients, and 3.6% (26 patients) among all 727 MTC patients. Simultaneous MTC and PTC were consistently smaller than nonsimultaneous MTC (6 vs. 13 mm for hereditary MTC, P = .16; 12 vs. 23 mm for sporadic MTC, P = .009; and 11 vs. 20 mm for any MTC, P = .008) and PTC (8 vs. 20 mm, P < .001). Simultaneous MTC and PTC increased among MTC and PTC patients over time: from 0% to 4.3% (PTC), from 0% to 4.6% (hereditary MTC), from 0% to 8.1% (sporadic MTC), and from 0% to 7.0% (any MTC). For sporadic MTC, these rates virtually doubled every 5 years. Of 6 patients with simultaneous hereditary MTC and PTC, 5 revealed late-onset REarranged during Transfection (RET) mutations (1 L790F carrier; 2 V804L and 2 S891A carriers).

CONCLUSIONS

Greater pathologic scrutiny, in addition to environmental changes, explains the surge of simultaneous MTC and PTC in Germany. More data are needed from additional geographic areas and populations to delineate individual contributions of these factors.

Basal and Stimulated Calcitonin and Procalcitonin by Various Assays in Patients with and without Medullary Thyroid Cancer

BACKGROUND

Calcitonin (CT) is a sensitive marker for evaluation of medullary thyroid cancer (MTC). However, CT measurement can vary with assay- and nonassay-dependent factors, and procalcitonin (PCT) measurement has been proposed for evaluating questionable increases in CT.

METHODS

We tested 2 fully automated CT assays (Immulite [IL] and Liaison [LIA]) and 1 nonautomated CT assay (IRMA, Medipan) and compared these results with PCT (Brahms Kryptor). We evaluated preanalytical conditions and PCT cross-reactivity in sera of 437 patients with clinical conditions associated with hypercalcitoninemia. Additionally, we determined the true “nil” CT concentration in 60 thyroidectomized patients and defined CT cutoff concentrations for pentagastrin stimulation testing in 13 chronic kidney disease (CKD) patients and 10 MTC patients.

RESULTS

Markedly decreased CT concentrations were found after storage of sera for &gt;2 h at room temperature and &gt;6 h at 4 °C. Cutoff concentrations for basal and stimulated CT were disease and assay dependent. Proton pump inhibitor therapy was the most frequent reason for increased CT. PCT concentrations were higher in patients with MTC than in patients with CKD without infections (P &lt; 0.001). Whereas IL and LIA demonstrated comparable analytical quality, the IRMA gave increased CT concentrations in nil sera and showed cross-reactivity with PCT in patients with concomitant bacterial infection.

CONCLUSIONS

IL, LIA, and IRMA detected increased CT concentrations in non-MTC patients and discriminated MTC from CKD patients in pentagastrin tests. PCT assessment may be helpful in the diagnostic work-up of increased CT concentrations in questionable clinical circumstances.

[Calcitonin determination for early diagnosis of medullary thyroid cancer]

Calcitonin is considered to be a sensitive marker for medullary thyroid cancer (MTC) therefore early detection and surgical treatment may help to improve the clinical prognosis of MTC. Routine calcitonin measurement has therefore been recommended in the diagnostic evaluation of patients with nodular thyroid disease. In the case of elevated serum calcitonin (>20 pg/ml) stimulation testing is recommended to improve the predictive power for MTC particularly in patients with small nodules. Serum calcitonin measurement cannot reliably discriminate between micro-MTC (<10 mm) and C cell hyperplasia. In patients with stimulated calcitonin levels exceeding 100 pg/ml thyroidectomy is recommended because of a high inherent risk of MTC. Highly elevated basal and stimulated serum calcitonin levels are strongly suggestive of MTC with practical implications for surgical management.

Analytical validation of the Liaison Calcitonin_II-Gen (DiaSorin)

BACKGROUND

We validated the DiaSorin Liaison Calcitonin_II-Gen, an improved method for calcitonin (CT) measurements, compared this method with the Cisbio_h-CT kit and established the reference range of CT in a normal adult population.

METHODS

We determined the precision, functional sensitivity, traceability to the 2nd IS 89/620, linearity and measurement uncertainty, accuracy profile and β-expectation limits. We evaluated the specificity, the susceptibility to human anti-animal antibodies (HAMA), hook-effect and carry over. To establish a reference range, we selected 267 adults without renal insufficiency presenting with normal thyroid stimulating hormone (TSH), free thyroxin (T4) and calcium concentrations and without anti-thyroglobulin antibodies as our "reference" healthy population. We compared the method with Cisbio on 250 consecutive and 45 samples from a post-pentagastrin stimulation test.

RESULTS

Precision (expressed as CV) was < 10% for the measurement range, functional sensitivity: 5.3 ng/L and the method was found linear until to a 1/10 dilution. Uncertainty ranged from 25% to 7.2%, and the risk that one result falls out of the ± 20% acceptance limits was < 5% between 2.9 and 1513 ng/L. The Bland and Altman plot showed no systematic bias between the two methods. The test is still prone to HAMA influence, does not present any hook-effect, although carry over was observed. Ninety-five percent of our adult reference population showed CT concentrations < 7.4 ng/L, with an important gender difference: 95% of the men showed CT values < 9.8 ng/L, whereas 95% of women were < 4.0 ng/L.

CONCLUSIONS

The Liaison Calcitonin_II-Gen is an analytically robust method. The important difference in gender observed in our population might lead to re-evaluation of the generally used "10 ng/L" cut-off in a multicentre prospective study.

Benefit of measuring basal serum calcitonin to detect medullary thyroid carcinoma in a Danish population with a high prevalence of thyroid nodules

BACKGROUND

Routine measurement of serum calcitonin to detect medullary thyroid carcinoma (MTC) continues to be fiercely debated, although less attention has been paid to the positive predictive value (PPV) of this method.

METHODS

We collected data from 959 patients with nontoxic nodular goiter; thyroidectomy was performed in 307 of these patients.

RESULTS

Thirty-nine patients had elevated serum calcitonin; 6 of these patients had MTC detected by the initial diagnostic setup. No additional patient in the cohort was registered in the Danish Thyroid Cancer Database, reflecting that all patients with MTC were classified correctly initially. The sensitivity of serum calcitonin for detection of MTC was 100%, the specificity was 95.3%, the positive predictive value was 15.4%, and the negative predictive value was 100%.

CONCLUSION

Serum calcitonin has high sensitivity and specificity for detection of MTC. The low PPV might lead to unnecessary thyroid surgery. Thus, the result of serum calcitonin measurement should always be interpreted in the context of other clinical variables.

Decreasing tumor size of thyroid cancer in Germany: institutional experience 1995-2009

OBJECTIVE

Decreasing tumor size in a population over time is widely interpreted as a measure of effectiveness of cancer screening programs. Nonetheless, thyroid cancer size is rarely analyzed as a function of time. This study aimed to explore secular trends of thyroid cancer diameter in Germany.

DESIGN

Retrospective analysis of 1644 thyroid cancer patients from a large referral center for thyroid cancer (1995-2009).

METHODS

Calculation of largest tumor diameters for each type of cancer as a function of time periods and birth cohorts.

RESULTS

Over the past 25 years, subdivided into 5-year periods by year of thyroidectomy (1985-1989; 1990-1994; 1995-1999; 2000-2004; 2005-2009), tumor diameters diminished from 25 to 16 mm (P=0.025) for medullary thyroid cancer and from 28 to 18 mm (P=0.017) for papillary thyroid cancer. This reduction was greater for hereditary medullary thyroid cancer (from 27 to 11 mm; P=0.088) than sporadic medullary thyroid cancer (from 23 to 19 mm; P=0.11). No decline was observed for follicular thyroid cancer (means of 45 to 42 mm; P=0.52). From the first (1921-1940) to the most recent birth cohort (1981-2000), tumor size fell from 22 to 10 mm (P<0.001) for medullary thyroid cancer, from 24 to 22 mm (P<0.001) for papillary thyroid cancer, and from 49 to 38 mm (P=0.011) for follicular thyroid cancer. The reduction of medullary thyroid cancers affected exclusively patients with hereditary disease (from 20 to 7 mm; P<0.001).

CONCLUSION

The consistency and robustness of these data signify powerful secular trends toward smaller papillary, follicular, and medullary thyroid cancers. The causes and consequences of these trends warrant further investigation.

Calcitonin screening and pentagastrin testing: predictive value for the diagnosis of medullary carcinoma in nodular thyroid disease

CONTEXT

Serum calcitonin (hCT) measurement may be useful for detecting medullary thyroid carcinoma (MTC), but the routine use of hCT after pentagastrin stimulation to screen patients with nodular thyroid disease remains controversial.

PATIENTS

A total of 1007 patients (567 females and 440 males) with nodular thyroid disease and a mean age of 55+/-14 (mean+/-S.D.) years were included in the study. All patients did not have impaired renal function, bacterial infection, alcohol and drug abuse, pseudohypoparathyroidism, or proton-pump inhibitor therapy. Individuals referred with known elevation of hCT, Graves' disease, or autoimmune thyroid disease were not considered or included in this investigation.

METHODS

Serum hCT levels were determined under basal conditions, and when basal values were >or=10 and <100 pg/ml, testing was repeated after pentagastrin stimulation. Patients with basal or stimulated levels >100 pg/ml were referred for surgery.

RESULTS

hCT levels >10 pg/ml were increased in 17 patients (1.7%). One patient had a basal hCT level of 4400 pg/ml with a histological confirmation of a MTC. In this patient, pentagastrin test was not performed. Sixteen patients with basal hCT between 10 and 100 pg/ml underwent pentagastrin-stimulated hCT measurement. Of 16 patients, 4 had stimulated hCT>100 pg/ml. Of 17 patients with hCT>10 pg/ml, 2 had MTC, and of 17 patients, 3 had C-cell hyperplasia. In total, two patients (0.20%) had a histologically verified MTC.

CONCLUSIONS

Basal hCT measurement together with pentagastrin-stimulated hCT measurement in cases of basal hCT>10 pg/ml detects MTC in 0.20% of patients with nodular thyroid disease. Whether this high incidence of MTC has major implications or not has to be discussed, but it should be considered as a useful and recommended tool for early detection of MTC and to save patients' life.

Biomarker-based risk stratification for previously untreated medullary thyroid cancer

CONTEXT

Preoperative neck ultrasonography may yield false-negative findings in more than one-third of medullary thyroid cancer (MTC) patients. If not cleared promptly, cervical lymph node metastases may emerge subsequently. Reoperations entail an excess risk of surgical morbidity and may be avoidable.

OBJECTIVE

This comprehensive investigation aimed to evaluate in a head-to-head comparison the clinical utility of pretherapeutic biomarker serum levels (basal calcitonin; stimulated calcitonin; carcinoembryonic antigen) for indicating extent of disease and providing biochemical stratification of pretherapeutic MTC risk.

DESIGN

This was a retrospective analysis.

SETTING

The setting was a tertiary referral center.

PATIENTS

Included were 300 consecutive patients with previously untreated MTC.

INTERVENTIONS

The intervention was compartment-oriented surgery.

MAIN OUTCOME MEASURE

Stratified biomarker levels were correlated with histopathologic extent of disease.

RESULTS

Higher biomarker levels reflected larger primary tumors and more lymph node metastases. Stratified basal calcitonin serum levels correlated better (r = 0.59) with the number of lymph node metastases than carcinoembryonic antigen (r = 0.47) or pentagastrin-stimulated calcitonin (r = 0.40) levels. Lymph node metastases were present in the ipsilateral central and lateral neck, contralateral central neck, contralateral lateral neck, and upper mediastinum, respectively, beyond basal calcitonin thresholds of 20, 50, 200, and 500 pg/ml. Bilateral compartment-oriented neck surgery achieved biochemical cure in at least half the patients with pretherapeutic basal calcitonin levels of 1,000 pg/ml or less but not in patients with levels greater than 10,000 pg/ml.

CONCLUSIONS

Most newly diagnosed MTC patients, i.e. those with pretherapeutic basal calcitonin levels greater than 200 pg/ml, may need bilateral compartment-oriented neck surgery to reduce the number of reoperations.

[Surgery of thyroid carcinoma]

The 5 main types of thyroid cancer (papillary, PTC, follicular, FTC, poorly differentiated, PDTC undifferentiated, UTC, medullary, MTC) not only differ regarding morphology, pathogenesis, genetics,and pathophysiology (iodine metabolism, thyroglobulin and calcitonin production), but also concerning tumor biology, metastatic behavior (lymphogenous, locally invasive and hematogenous routes) and prognosis. Knowledge of these features is the basis of the surgical concept of one or two-stage thyroidectomy, the exceptions and the concept of locoregional lymph node dissection. Lymph node surgery plays an important role in those cancers exhibiting mainly lymph node metastases (PTC, MTC) not only due to frequent recurrences but also due to its potential curative intent. Differentiated carcinomas may have an acceptable prognosis despite local invasion of the cervical aerodigestive system, thus resections are justified when technical prerequisites are given.