Prevalence of sporadic medullary thyroid carcinoma: the importance of routine measurement of serum calcitonin in the diagnostic evaluation of thyroid nodules

Prevalence and significance of indeterminate calcitonin values in patients with thyroid nodules: A systematic review and meta-analysis

BACKGROUND

Although calcitonin (Ctn) measurement is recognized as the most accurate diagnostic test for medullary thyroid carcinoma (MTC), its routine execution is not universally accepted for several reasons, including the lack of recommendations for managing indeterminate Ctn values (ICV); such as 10-to-100 pg/mL. This study aimed to gather data on 1) the frequency of ICV among patients undergoing Ctn test and 2) the MTC rate among patients with ICV.

METHODS

This review was conducted according to the Meta-analyses Of Observational Studies in Epidemiology guidelines. PubMed and Cochrane databases were searched, with no language restrictions. The final search was completed on January 2023. Then, quality assessment and proportion meta-analyses were performed.

RESULTS

The online search retrieved 233 articles and 15 were included for quantitative analysis. The risk of bias was low. The number of patients undergone Ctn testing was 29,533. The pooled percentage of those with ICV was 1.7% (95% confidence interval [CI]:1.2-2.3). The pooled proportion of MTC incidence among patients with ICV was 9.6% (95% CI:5-14.1). Heterogeneity was explained by the covariates of Ctn assay sensitivity and the resection rate. The subgroup with Ctn 10-20 pg/mL showed a significantly lower MTC rate than the subgroup with Ctn 20-100 pg/mL.

CONCLUSIONS

The percentage of ICV among patients with thyroid nodules who underwent Ctn testing is negligible. The rate of MTC in patients with ICV cannot be overlooked. Among the ICV intervals, the risk of MTC increases significantly when Ctn is above 20 pg/mL.

The dilemma of routine testing for calcitonin thyroid nodule's patients to detect or exclude medullary carcinoma: one single negative test should be valuable as rule-out strategy to avoid further calcitonin measurements over time

PURPOSE

While calcitonin (CT) measurement is recognized as the most accurate tool to diagnose medullary thyroid carcinoma (MTC), its routine use in patients with thyroid nodule (TN) is not universally accepted. The present study raised the question whether a TN patient with an initial normal CT can have suspicious CT levels (i.e., at least >20 pg/ml) later during his follow-up.

METHODS

The historical database of our institution was searched to select TN patients undergone multiple CT tests, having an initial normal CT, and clinically followed up for years. The event of a CT above 20 pg/ml (mild-to-moderate suspicion) and 100 pg/ml (high suspicion) was searched in the follow-up of the included patients.

RESULTS

According to the study design, the study sample encompassed 170 patients (131 female, 39 male) with initial CT value ≤10 pg/ml. On the first CT test, patients were 54.8 years and median CT was 2.1 pg/ml in both females and males. Over a period of 14.5 years and a median clinical follow-up of patients of 53.0 (23.9-102.5) months, MTC could be excluded by histology or cytology in 109 (64%) and clinically in the remaining ones. On the follow-up over time, no patients had CT >20 pg/ml and only two cases had CT just above 10 pg/ml.

CONCLUSION

According to the present results, one single CT testing with normal value could be reasonably used as a rule-out strategy in patients with TN to avoid further CT measurements.

Thresholds of Basal- and Calcium-Stimulated Calcitonin for Diagnosis of Thyroid Malignancy

Since medullary thyroid carcinoma is an aggressive cancer, it is important to have an early detection based on stimulated calcitonin (CT), especially when basal-CT is slightly elevated. The objective of this work was to set specific thresholds for basal-CT- and calcium-stimulated calcitonin for prediction of thyroid malignancy in female population. The study included 2 groups: group A-women with elevated basal-CT (>9.82 pg/ml) and group B-women with normal basal-CT (control group). After calcium stimulation test precise protocol, histopathological reports of those that required surgery were correlated with both basal and stimulated calcitonin. The best basal and stimulated calcitonin cut-offs for distinguishing female patients with medullary thyroid carcinoma or C-Cell-hyperplasia from other pathologies or normal cases were: 12.9 pg/ml, respectively 285.25 pg/ml. For basal-CT above 30 pg/ml, malignancy was diagnosed in 9/9 patients (100%): 9 MTC. For stimulated calcitonin above 300 pg/ml, malignancy was diagnosed in 17/21 patients (80.95%): 12 MTC and 5 papillary thyroid carcinomas. The smallest nodule that proved to be medullary thyroid carcinoma had only 0.56/0.34/0.44 cm on ultrasound, with no other sonographic suspicious criteria. In conclusion, we have identified in Romanian female population basal and stimulated calcitonin thresholds to discriminate medullary thyroid carcinoma or C-Cell-hyperplasia from other cases. We recommend thyroid surgery in all women with stimulated calcitonin above 285 pg/ml. Further studies on larger groups are necessary to establish and confirm male and female cut-offs for early diagnosis of medullary thyroid carcinoma, and interestingly, maybe for macro-papillary thyroid carcinomas alike. The calcium administration has minimum side-effects, but continuous cardiac monitoring is required.

Encapsulated papillary variant of medullary carcinoma of thyroid with extensive cystic change: an extremely rare presentation

Papillary variant of medullary carcinoma of the thyroid is an unusual subtype with many diagnostic challenges. The authors report a case of papillary variant of thyroid medullary carcinoma in a 37-year-old female, who presented with complaints of pain in the thyroid nodule for the latter two months. Contrast enhanced computed tomography (CECT) neck revealed an enlarged and heterogeneously enhancing left lobe of thyroid. This was followed by hemithyroidectomy for suspicion of colloid goitre. Gross examination of the cut surface of the thyroid parenchyma had a sponge like appearance. On histopathology a diagnosis of encapsulated papillary variant of medullary carcinoma thyroid was made with the help of special stains and immunohistochemistry (IHC).

Calcitonin Levels in Thyroid Disease Are Not Affected by Autoimmune Thyroiditis or Differentiated Thyroid Carcinoma

INTRODUCTION

Association between hypercalcitoninemia and pathological conditions such as autoimmune thyroiditis (AIT) or differentiated thyroid carcinoma (DTC) has been addressed, with conflicting results. We evaluated the prevalence and the clinical relevance of elevated basal serum calcitonin (CT) levels in non-neoplastic (nodular goiter [NG] and AIT) and neoplastic thyroid diseases (DTC).

METHODS

We retrospectively evaluated 3,250 consecutive patients with thyroid nodular disease who underwent fine-needle aspiration cytology with adequate sample. After exclusion of medullary thyroid cancer (MTC) patients were divided according to the presence/absence of thyroid autoimmunity into NG or nodular autoimmune thyroiditis (N-AIT) and, according to cytological results, in benign or suspicious/malignant nodules.

RESULTS

One hundred ninety-seven/3,250 patients (6.0%) showed CT level >10 pg/mL. In 11/3,250 (0.3%) cases, a final histological diagnosis of MTC was made, while the remaining 186/3,250 patients (5.7%) had non-MTC-related hypercalcitoninemia (CT > 10 pg/mL). According to cytological diagnosis, the rate of hypercalcitoninemia was similar in class II and class V-VI groups (5.4 vs. 6.9%, p = 0.4). The occurrence of hypercalcitoninemia was significantly higher in patients with NG (166/2,634 [6.3%]) than in patients with N-AIT (20/605 [3.3%]) (p = 0.004). However, after matching by sex, no difference was found between the 2 groups (NG and N-AIT). These results were confirmed in 598 patients submitted to surgery.

CONCLUSIONS

AIT and DTC seem not to affect serum CT levels in patients with thyroid nodules. Therefore, hypercalcitoninemia, in these patients, should be submitted to the same diagnostic workup than patients without AIT or DTC.

Diagnostic accuracy of routine calcitonin measurement for the detection of medullary thyroid carcinoma in the management of patients with nodular thyroid disease: a meta-analysis

OBJECTIVE

The usefulness of routine calcitonin measurement for early detection of medullary thyroid carcinoma (MTC) in patients with nodular thyroid disease (NTD) has been investigated in various studies. Recently, a Cochrane review has been published on this issue, but a meta-analysis is lacking yet. Therefore, we performed this meta-analysis.

METHODS

We performed an electronic search using PubMed/Medline, Embase and the Cochrane Library. Studies assessing the diagnostic accuracy of routine calcitonin measurement for detecting MTC in patients with NDT were selected. Statistics were performed by using Stata software, risk of bias was assessed using Review Manager version 5.3.

RESULTS

Seventeen studies, involving 74,407 patients were included in the study. Meta-analysis, using the bivariate random effects model and the hierarchical summary receiver operating characteristic (HSROC) curve revealed the following pooled estimates: sensitivity 0.99 (95% CI, 0.81-1.00), specificity 0.99 (95% CI, 0.97-0.99), positive likelihood ratio (L+) 72.4 (95% CI, 32.3-162.1), and negative likelihood ratio (L-) 0.01 (95% CI, 0.00-0.23). Meta-regression analysis showed that the threshold of basal calcitonin is an independent factor, but in particular performing stimulation test is not an independent factor.

CONCLUSIONS

We showed that routine basal serum calcitonin measurement in the management of patients with thyroid nodules is valuable for the detection of MTC. However, the published cut-off values should be considered and, if applicable, the patients monitored in a wait-and-see strategy by experienced physicians to avoid overtreatment.

Cost-effectiveness of routine calcitonin screening and fine-needle aspiration biopsy in preoperative diagnosis of medullary thyroid Cancer in the United States

OBJECTIVES

examine the cost-effectiveness of routine Calcitonin (Ctn) screening test in the United States.

MATERIALS AND METHODS

Markov chain model was developed that compares fine-needle aspiration biopsy (FNAB) with Ctn screening vs. FNAB-only in the evaluation of a thyroid nodule with non-highly suspicious findings. Follow-up time was set as 10 years. Costs and probabilities values were obtained from literature, and National Cancer Database. Cost data is expressed in U.S$ and effectiveness is expressed in Quality-adjusted-life-year (QALY). Incremental cost-effectiveness ratio (ICER) was calculated comparing both study arms.

RESULTS

Routine Ctn screening was cost-effective compared to FNAB-only in all tested categories except when cutoff value of 10 pg/ml was applied. Among the tested categories, the application of universal routine Ctn screening with Ctn value > 50 pg/ml considered a positive test produced the most cost-saving scenario. The final accrued cost at the end of 10 years in the FNAB-only arm was $4238.93 with a final effectiveness of 8.717 QALY. While the final cost in the FNAB-with routine Ctn screening was $4345.04 with a final effectiveness of 8.722 QALY. ICER of routine Ctn screening compared to FNAB-only was $23278.61/QALY (<Willing-To-Pay threshold of $50,000/QALY). Based on sensitivity analyses, Ctn testing is cost-effective if the test cost is less than $236.03.

CONCLUSIONS

Routine Ctn screening is a cost-effective strategy in US if the cost is less than $236.03. Although Ctn screening is not perfect in detecting MTC at early stages, it is a cost-effective alternative of discovering MTC after thyroid lobectomy or on follow-up of a thyroid nodule.

Calcitonin testing for detection of medullary thyroid cancer in people with thyroid nodules

BACKGROUND

Thyroid nodules are very common in general medical practice, but rarely turn out to be a medullary thyroid carcinoma (MTC). Calcitonin is a sensitive tumour marker for the detection of MTC (basal calcitonin). Sometimes a stimulation test is used to improve specificity (stimulated calcitonin). Although the European Thyroid Association's guideline advocates calcitonin determination in people with thyroid nodules, the role of routine calcitonin testing in individuals with thyroid nodules is still questionable.

OBJECTIVES

The objective of this review was to determine the diagnostic accuracy of basal and/or stimulated calcitonin as a triage or add-on test for detection of MTC in people with thyroid nodules.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and Web of Science from inception to June 2018.

SELECTION CRITERIA

We included all retrospective and prospective cohort studies in which all participants with thyroid nodules had undergone determination of basal calcitonin levels (and stimulated calcitonin, if performed).

DATA COLLECTION AND ANALYSIS

Two review authors independently scanned all retrieved records. We extracted data using a standard data extraction form. We assessed risk of bias and applicability using the QUADAS-2 tool. Using the hierarchical summary receiver operating characteristic (HSROC) model, we estimated summary curves across different thresholds and also obtained summary estimates of sensitivity and specificity at a common threshold when possible.

MAIN RESULTS

In 16 studies, we identified 72,368 participants with nodular thyroid disease in whom routinely calcitonin testing was performed. All included studies performed the calcitonin test as a triage test. Median prevalence of MTC was 0.32%. Sensitivity in these studies ranged between 83% and 100% and specificity ranged between 94% and 100%. An important limitation in 15 of the 16 studies (94%) was the absence of adequate reference standards and follow-up in calcitonin-negative participants. This resulted in a high risk of bias with regard to flow and timing in the methodological quality assessment. At the median specificity of 96.6% from the included studies, the estimated sensitivity (95% confidence interval (CI)) from the summary curve was 99.7% ( 68.8% to 100%). For the median prevalence of MTC of 0.23%, the positive predictive value (PPV) for basal calcitonin testing at a threshold of 10 pg/mL was 7.7% (4.9% to 12.1%). Summary estimates of sensitivity and specificity for the threshold of 10 pg/mL of basal calcitonin testing was 100% (95% CI 99.7 to 100) and 97.2% (95% CI 95.9 to 98.6), respectively. For combined basal and stimulated calcitonin testing, sensitivity ranged between 82% and 100% with specificity between 99% and 100%. The median specificity was 99.8% with an estimated sensitivity of 98.8% (95% CI 65.8 to 100) .

AUTHORS' CONCLUSIONS

Both basal and combined basal and stimulated calcitonin testing have a high sensitivity and specificity. However, this may be an overestimation due to high risk of bias in the use and choice of reference standard The value of routine testing in patients with thyroid nodules remains questionable, due to the low prevalence, which results in a low PPV of basal calcitonin testing. Whether routine calcitonin testing improves prognosis in MTC patients remains unclear.

Routine calcitonin measurement in nodular thyroid disease management: is it worthwhile?

PURPOSE

To evaluate the diagnostic accuracy of routine calcitonin measurement in patients with nodular thyroid disease.

METHODS

Consecutive patients with nodular thyroid disease (n = 640) were studied. Serum calcitonin levels were measured under basal conditions, and when basal values were between 10-100 pg/mL, testing was repeated after pentagastrin (PG) stimulation. Patients with previously diagnosed or familial medullary thyroid cancer (MTC) were excluded. Patients were operated on when basal or stimulated calcitonin >100 pg/mL or when other surgical indications were present.

RESULTS

Four cases of MTC were identified. MTC was diagnosed in 75% of patients with basal calcitonin >100 pg/mL. One out of 11 patients with basal calcitonin between 10-100 pg/mL was diagnosed with MTC. PG stimulation resulted in elevation in 4 cases, where 1 case was diagnosed with MTC. Positive predictive value for basal calcitonin levels in the preoperative diagnosis of MTC was 5% for values between 10-100 pg/mL and 100% for values >100 pg/mL. Possible reasons for false positivity were papillary thyroid cancer in 17%, renal insufficiency in 8.3%, Hashimoto thyroiditis in 17% and β-blocker use in 33%. Positive predictive value for the PG test (>100 pg/mL) was 25% in the entire series. The cost of adding calcitonin measurement (±PG stimulation) to the preoperative work-up, resulted in €912.68 per MTC patient to detect the disease.

CONCLUSION

Basal calcitonin measurement together with PG stimulation in cases of basal calcitonin >10 pg/mL detects MTC in 0.62% of patients with nodular thyroid disease.

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.

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.

Incidental medullary thyroid microcarcinoma revealed by mild increase of preoperative serum calcitonin levels: therapeutic implications

To investigate whether further, diagnostic procedures should be recommended in patients with slight increase of preoperative serum basal calcitonin (bCT) levels in whom surgical treatment can be recommendable. Fourteen consecutive patients with nodular thyroid disease underwent thyroidectomy in our center for suspected medullary thyroid microcarcinoma (MTC) because their serum bCT levels were slightly higher than the upper limit of normal range. Serum bCT was measured by radioimmunoassay, normality range = 0-20 ng/L. Surgical specimens were examined by the same pathologist using histologic and immunohistochemistry techniques. An extensive search for parafollicular C-cell hyperplasia (CCH) and/or microscopic MTC foci was performed. At preoperative ultrasound, a single thyroid nodule was depicted in three patients while a multinodular goiter in 11. The bCT values ranged between 24.4 and 94.6 ng/L, median 42.2 ng/L while the pentagastrin-stimulated CT (sCT) values by pentagastrin test ranged between 61.5 and 1,262 ng/L, median 245.0 ng/L. Total thyroidectomy was performed in 13 patients, and lobectomy in the other one; central node dissection was also performed in eight cases. At histology, MTC was diagnosed in nine patients (64.3 %), showing a median maximum diameter of 6.1 mm (range, 1.5-17 mm); CCH was diagnosed in the other five patients (35.7 %). The pentagastrin stimulation test was obtained in all patients. It is worth noting that a very high increase of sCT >100 ng/mL was observed in 5/9 patients with MTC and in 2/4 patients with HCC, therefore suggesting the absence of a relationship between the entity of response to pentagastrin test with a specific pathology (MTC vs. HCC). In six patients, the MTC was the nodule on which preoperative FNAC had been performed, while in other three patients preoperative FNAC had been performed on a different nodule from the MTC. Based on our experience, in case of the pentagastrin stimulation test with sCT <100 ng/L and a single nodule, the CT assay on FNAC may be useful, subsequently lobectomy with definitive histological diagnosis is recommended. In case of the Pg test with sCT <100 ng/L and bilateral goiter, total thyroidectomy with histological diagnosis is recommended. In this way, as for the surgical procedure, total thyroidectomy is recommended in cases of bilateral goiter, while lobectomy can be offered for cases with single nodes with serum dosage of bCT in the strict follow up. In case of the pentagastrin stimulating test with sCT <100 ng/L and bilateral goiter, total thyroidectomy with histological diagnosis is recommended.

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.

False positive results using calcitonin as a screening method for medullary thyroid carcinoma

The role of serum calcitonin as part of the evaluation of thyroid nodules has been widely discussed in literature. However there still is no consensus of measurement of calcitonin in the initial evaluation of a patient with thyroid nodule. Problems concerning cost-benefit, lab methods, false positive and low prevalence of medullary thyroid carcinoma (MTC) are factors that limit this approach. We have illustrated two cases where serum calcitonin was used in the evaluation of thyroid nodule and rates proved to be high. A stimulation test was performed, using calcium as secretagogue, and calcitonin hyper-stimulation was confirmed, but anatomopathologic examination did not evidence medullar neoplasia. Anatomopathologic diagnosis detected Hashimoto thyroiditis in one case and adenomatous goiter plus an occult papillary thyroid carcinoma in the other one. Recommendation for routine use of serum calcitonin in the initial diagnostic evaluation of a thyroid nodule, followed by a confirming stimulation test if basal serum calcitonin is showed to be high, is the most currently recommended approach, but questions concerning cost-benefit and possibility of diagnosis error make the validity of this recommendation discussible.

Calcitonin estimation in patients with nodular goiter and its significance for early detection of MTC: european comments to the guidelines of the American Thyroid Association

One of the most discussed and controversial issue in the management of thyroid nodules is the need to perform a routine measurement of serum Calcitonin (Ct) in all cases. The American Thyroid Association guidelines do not recommend in favor or against this procedure since they retain that there are not enough evidences that it can determine an advantage to the health outcomes of these patients. This is not the view of many European experts who met in Lisbon in 2009 at the European Thyroid Association-Cancer Research Network meeting to discuss all the still open controversial issues on the management of medullary thyroid cancer patients.

This paper is focused on the routine measurement of serum Ct in all patients with thyroid nodule(s): the evidences, the rational and the benefits of this procedure are deeply analysed following the discussion that was done in Lisbon. The conclusions reached at that time are reported in detail.

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.

Clinical review: Incidentally discovered medullary thyroid cancer: diagnostic strategies and treatment

CONTEXT

Medullary thyroid carcinoma (MTC) is diagnosed only after thyroidectomy in approximately 10-15% of cases. This delay in diagnosis can have adverse consequences such as missing underlying pheochromocytoma or hyperparathyroidism in unrecognized multiple endocrine neoplasia type 2 and choosing a suboptimal extent of surgery. Barriers to accurate preoperative diagnosis and management strategies after the discovery of occult MTC are reviewed.

EVIDENCE ACQUISITION

We reviewed PubMed (1975-September 2010) using the search terms medullary carcinoma, calcitonin, multinodular goiter, Graves' disease, calcium/diagnostic use, and pentagastrin/diagnostic use.

EVIDENCE SYNTHESIS

The combined prevalence of occult MTC in thyroidectomy series is approximately 0.3%. Routine calcitonin measurement in goiter patients identifies C-cell hyperplasia as well as MTC. Challenges include interpreting intermediate values and unavailability of pentagastrin stimulation testing in the United States. Early studies have begun to identify appropriate cutoff values for calcium-stimulated calcitonin. For management of incidentally discovered MTC, we highlight the role of early measurement of calcitonin and carcinoembryonic antigen, RET testing, and comprehensive neck ultrasound exam to direct further imaging, completion thyroidectomy, and lymph node dissection.

CONCLUSIONS

Occult MTC is an uncommon, but clinically significant entity. If calcium stimulation testing cutoff data become well-validated, calcitonin screening would likely become more widely accepted in the diagnostic work-up for thyroid nodules in the United States. Among patients with incidental MTC, those with persistently elevated serum calcitonin levels, positive RET test, or nodal disease are good candidates for completion thyroidectomy and lymph node dissection in selected cases, whereas patients with undetectable calcitonin, negative RET testing, and no sonographic abnormalities often may be watched conservatively.

Medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) accounts for 5-8% of all thyroid cancers. MTC is mainly sporadic in nature, but an hereditary pattern [multiple endocrine neoplasia type 2 (MEN 2)] is present in 20-30% of cases, transmitted as an autosomal-dominant trait due to germline mutations of the RET proto-oncogene. About 98% of patients with MEN 2 have germline mutations in exons 5, 8, 10, 11, 13, 14, 15 or 16 of the RET gene. The primary treatment of both hereditary and sporadic forms of MTC is total thyroidectomy and removal of all neoplastic tissue present in the neck. The therapeutic option for lymph node surgery should be dictated by the results of presurgical evaluation. After total thyroidectomy, measurements of serum calcitonin (CT) and carcinoembryonic antigen are of paramount importance in the postsurgical follow-up of patients with MTC as they reflect the presence of persistent or recurrent disease. Complete remission is demonstrated by undetectable and stimulated serum CT measurement. On the contrary, if serum CT is detectable under basal conditions or becomes detectable after stimulation, the patient is probably not cured, but imaging techniques will not demonstrate any disease until serum CT approaches levels >150 pg/ml. The tumour metastasises early to both paratracheal and lateral cervical lymph nodes. Metastases outside the neck may occur in the liver, lungs, bones and, less frequently, brain and skin. Surgery is the main treatment for local and distant metastases whenever feasible. Systemic chemotherapy with dacarbazine, 5-fluorouracil and doxorubicin (alone or in combination) has shown very limited efficacy, achieving only partial responses in the range of 10-20% and of short duration. Several kinase inhibitors are currently under evaluation and preliminary results are promising. Familial cases must be identified by searching for RET proto-oncogene mutations in the proband and in family members. Carriers of the RET gene are candidates for prophylactic thyroidectomy at different ages depending on the risk associated with the specific RET mutations.

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.

Spurious hypercalcitoninemia in patients with nodular thyroid disease induced by heterophilic antibodies

BACKGROUND

Serum calcitonin is the most useful tumor marker for the diagnosis and follow-up of medullary thyroid carcinoma (MTC). Spurious hypercalcitoninemia caused by heterophilic antibody interference (HAI) is rarely found in patients without MTC.

METHODS

We studied 2 patients with hypercalcitoninemia and thyroid nodules, but no evidence of MTC on fine-needle aspiration cytology. We performed calcium stimulation tests, measured serum calcitonin with another calcitonin kit, performed dilution tests, and remeasured serum calcitonin after applying heterophilic blocking tubes.

RESULTS

In a 31-year-old woman with no response to the calcium stimulation test, serum calcitonin was <5 pg/mL using another kit. After we applied heterophilic blocking tubes, the serum calcitonin level decreased to normal range. We concluded that patient had spurious hypercalcitoninemia. In a 63-year-old woman, all tests revealed that the patient had true hypercalcitoninemia. The patient underwent total thyroidectomy that revealed MTC.

CONCLUSIONS

We suggest that patients suspected for spurious hypercalcitoninemia should undergo further investigation due to HAI.

Mild hypercalcitoninaemia and sporadic thyroid disease

Background

Not operating on patients with mild hypercalcitoninaemia (MHCT) and sporadic thyroid disease carries the risk of omitting curative surgery for medullary thyroid cancer, but systematic surgery would result in unnecessary treatment of benign pathology. This study reviewed the management of MCHT and non-hereditary thyroid disease in one centre.

Methods

MCHT was defined as an increase in basal and stimulated calcitonin levels not exceeding 30 and 200 pg/ml respectively. Over 15 years, 125 patients who presented with MCHT and sporadic thyroid disease were followed. Surgery was indicated only if there were local pressure symptoms or suspicious histomorphological changes in solitary nodules.

Results

Fifty-five patients underwent total thyroidectomy and 18 unilateral total lobectomy. Histological examination revealed medullary microcarcinoma in six patients (two women and four men). C-cell hyperplasia was found in 54 patients (74 per cent) and 13 (18 per cent) harboured no C-cell pathology. Calcitonin levels stabilized after lobectomy and became undetectable following thyroidectomy. They normalized during follow-up in a third of patients who did not have surgery.

Conclusion

Not all patients with MHCT and sporadic thyroid disease require surgery.

Assessment of nodular goitre

Nodular goitres are enlargements of the thyroid gland. In the absence of thyroid dysfunction, autoimmune thyroid disease, thyroiditis and thyroid malignancy, they constitute an entity described as non-toxic nodular goitre, which occurs both endemically and sporadically. In the early phase of goitrogenesis, goitres are diffuse and, with time, such goitres tend to become nodular. Concomitantly, thyroid function often becomes autonomous, and therefore the patients gradually develop hyperthyroidism. Some non-toxic goitre patients have no symptoms at all, or just complaints of cosmetic disfigurement. In the diagnostic evaluation protocol, neck palpation and several imaging methods are available: ultrasonography (US), the new developed US elastography, scintigraphy, computed tomography (CT) scan and magnetic resonance imaging (MRI). Fine-needle aspiration biopsy (FNAB) provides the most direct and specific information about a thyroid nodule. Recently, a combination of cytology and molecular testing has shown significant improvement in the diagnostic accuracy and allowed for better prediction of malignancy in thyroid nodular disease.

Nodular disease and parafollicular C-cell distribution: results from a prospective and retrospective clinico-pathological study on the thyroid isthmus

OBJECTIVE

The isthmus represents a peculiar, as yet partially unexplored, thyroid gland area.

AIM OF THE STUDY

To assess i) the prevalence and clinico-pathological features of solitary thyroid isthmic nodules (STIN); ii) the frequency of medullary thyroid carcinoma (MTC) arising from the isthmus; and iii) the C-cell distribution in the isthmus of patients with MTC and benign nodular thyroid disease (NTD).

SUBJECTS AND METHODS

Patients referred from 2006 to 2008 for STIN were prospectively recruited, and underwent serum calcitonin (C(t)) measurement and fine needle aspiration cytology (FNAC). MTCs diagnosed from 1993 to 2005 were retrospectively searched. Immunohistochemistry was performed using anti-C(t) antibodies on lateral lobes and isthmi of 50 benign NTD and 50 MTC cases.

RESULTS

From 1993 to 2005, 150 patients underwent surgery for MTC. All patients had the neoplasm located in lateral thyroid lobes, none in the isthmus. In the 3 years following, 192 STIN patients (40 (21%) males, 152 (79%) females; mean age: 46.2+/-7.1 years; 6.4% of NTD subjects) were recruited. All had normal C(t) concentrations. FNAC was malignant or suspicious for malignancy in 14 (7.3%) patients. Histology found malignancy in 17 (9%) cases, MTC in none. C cells were disclosed in lateral thyroid lobes of 100% MTC and 77% benign NTD patients; isthmi were free of C cells in either group.

CONCLUSIONS

STINs are significantly less likely to be MTC in patients presenting with sporadic disease. Therefore, C(t) screening is not warranted in these subjects. Nonetheless, STINs are more likely to be neoplastic and deserve equal attention as those of the lateral lobes.

Medullary thyroid cancer: management guidelines of the American Thyroid Association

BACKGROUND

Inherited and sporadic medullary thyroid cancer (MTC) is an uncommon and challenging malignancy. The American Thyroid association (ATA) chose to create specific MTC Clinical Guidelines that would bring together and update the diverse MTC literature and combine it with evidence-based medicine and the knowledge and experience of a panel of expert clinicians.

METHODS

Relevant articles were identified using a systematic PubMed search and supplemented with additional published materials. Evidence-based recommendations were created and then categorized using criteria adapted from the United States Preventive Services Task Force, Agency for Healthcare Research and Quality.

RESULTS

Clinical topics addressed in this scholarly dialog included: initial diagnosis and therapy of preclinical disease (including RET oncogene testing and the timing of prophylactic thyroidectomy), initial diagnosis and therapy of clinically apparent disease (including preoperative testing and imaging, extent of surgery, and handling of devascularized parathyroid glands), initial evaluation and treatment of postoperative patients (including the role of completion thyroidectomy), management of persistent or recurrent MTC (including the role of tumor marker doubling times, and treatment of patients with distant metastases and hormonally active metastases), long-term follow-up and management (including the frequency of follow-up and imaging), and directions for future research.

CONCLUSIONS

One hundred twenty-two evidence-based recommendations were created to assist in the clinical care of MTC patients and to share what we believe is current, rational, and optimal medical practice.

Sporadic medullary thyroid carcinoma: clinical data from a university hospital

INTRODUCTION

Medullary thyroid carcinoma may occur in a sporadic (s-medullary thyroid carcinoma, 75%) or in a multiple endocrine neoplasia type 2 form (MEN2, 25%). These clinical forms differ in many ways, as s-medullary thyroid carcinoma cases are RET-negative in the germline and are typically diagnosed later than medullary thyroid carcinoma in MEN2 patients. In this study, a set of cases with s-medullary thyroid carcinoma are documented and explored.

PURPOSE

To document the phenotypes observed in s-medullary thyroid carcinoma cases from a university group and to attempt to improve earlier diagnosis of s-medullary thyroid carcinoma. Some procedures for diagnostics are also recommended.

METHOD

Patients (n=26) with apparent s-medullary thyroid carcinoma were studied. Their clinical data were reviewed and peripheral blood was collected and screened for RET germline mutations.

RESULTS

The average age at diagnosis was 43.9 years (+/- 10.82 SD) and did not differ between males and females. Calcitonin levels were increased in all cases. Three patients presented values that were 100-fold greater than the normal upper limit. Most (61.54%) had values that were 20-fold below this limit. Carcinoembryonic antigen levels were high in 70.6% of cases. There was no significant association between age at diagnosis, basal calcitonin levels or time of disease onset with thyroid tumor size (0.6-15 cm). Routine thyroid cytology yielded disappointing diagnostic accuracy (46.7%) in this set of cases. After total thyroidectomy associated with extensive cervical lymph node resection, calcitonin values remained lower than 5 pg/mL for at least 12 months in eight of the cases (30.8%). Immunocyto- and histochemistry for calcitonin were positive in all analyzed cases. None of the 26 cases presented germline mutations in the classical hotspots of the RET proto-oncogene.

CONCLUSION

Our cases were identified late. The basal calcitonin measurements and immunostaining for calcitonin were highly useful for diagnosing s-medullary thyroid carcinoma. The rate of complete patient recovery was low, and none of the parameters analyzed were useful predictors of the thyroid tumor size. Our findings support previous recommendations for routine serum calcitonin evaluation and immunostaining analysis involving single thyroid nodules.

Determination of calcitonin levels in C-cell disease: clinical interest and potential pitfalls

An elevated serum calcitonin level is a highly sensitive marker for medullary thyroid carcinoma (MTC) that can be used for screening, differential diagnosis, prognostic assessment, follow-up monitoring, and assessment of treatment response. Nevertheless, additional data are required to definitively support routine measurement of calcitonin levels in the initial work-up of patients with thyroid nodules, mainly because there is no convincing evidence that such testing actually reduces MTC-related mortality. By contrast, the prognostic value of measuring calcitonin levels preoperatively, postoperatively, and during follow-up of patients with MTC is widely acknowledged. Furthermore, determination of calcitonin levels is also used to evaluate the response of MTC to novel forms of systemic treatment, such as tyrosine kinase inhibitors. In this Review, we discuss the key issues surrounding the use of this laboratory test in the clinical management of patients with MTC.

Calculation and validation of a plasma calcitonin limit for early detection of medullary thyroid carcinoma in nodular thyroid disease

BACKGROUND

The early diagnosis of medullary thyroid carcinoma (MTC) is crucial for effective therapy. Elevated plasma calcitonin concentrations (pCT-Cs) are generally a specific and sensitive indicator for C-cell hyperplasia or MTC. The presence of thyroid nodules raises the possibility of MTC. Hence, in endemic goiter regions, there is a need for information regarding the pCT-C values that are indicative of C-cell hyperplasia or MTC. The aim of this study, therefore, was to determine an upper pCT-C to distinguish patients with and without MTC in a collective with nodular thyroid disease, and to give an estimation of the prevalence of MTC in an endemic goiter area.

METHODS

Basal pCT-C was measured in 21,928 patients with thyroid nodules living in central Germany, an area with endemic goiter due to previous iodine deficiency. In 218 subjects with pCT-Cs exceeding 10 ng/L, stimulated pCT-C was additionally determined, as suggested by the German consensus recommendation. A nominal normal range for basal pCT-C was calculated with data from 21,900 subjects without known MTC. The predicted upper limit was then validated using the known diagnoses of 376 patients with pCT-Cs exceeding 10 ng/L, 28 of whom presented with MTC.

RESULTS

For basal pCT-C, calculation of the three-sigma borders after logarithmic transformation revealed upper limits of the nominal normal range of 14.6 ng/L in females and 32.8 ng/L in males, respectively. However, three male patients with small MTCs had basal pCT-Cs between 15 and 33 ng/L. None of the patients with MTC had a basal pCT-C below 15 ng/L or an increase in pCT-C after pentagastrin stimulation that was less than 80 ng/L. In the basal pCT-C range between 15 and 50 ng/L (n = 192; eight with MTC), the positive predictive value for the detection of MTC was 4% in our group. Applying an upper limit for basal pCT-C of 15 ng/L in both sexes, 329 of the total of 21,928 patients exceeded this range. Among these, the final outcome is known in 231 subjects, including all 28 MTCs.

CONCLUSIONS

An upper limit of 15 ng/L instead of 10 ng/L for basal pCT-C is able to detect all MTC and reduce false-positive cases. The prevalence of MTC in nodular thyroid disease in our group was approximately 1.8 per thousand.

Functional nuclear medicine imaging of medullary thyroid cancer

Medullary thyroid cancer (MTC) originates from parafollicular C cells of the thyroid and accounts for 3-12% of all thyroid cancers. As opposed to other types of dedifferentiated thyroid tumours, MTC cells are highly functional, producing and secreting high amounts of calcitonin and carcinoembryonic antigen. As parafollicular C cells are of neural crest origin, MTC acts as a neuroendocrine tumour also and expresses somatostatin receptors. Although conventional radiological methods such as ultrasonography, computed tomography and magnetic resonance imaging are widely used in the primary diagnosis and staging, they often fail to localize the residual or recurrent disease because the majority of MTC recurrence presents as occult disease. Thus, owing to functional characteristics of MTC, functional imaging modalities of nuclear medicine play a major role in the diagnostic and therapeutic strategies for MTC. Among nuclear medicine modalities, Tc(V) -dimercaptosuccinic acid, In-octreotide and I/I-meta-iodobenzylguanidine are commonly used in the diagnostic and even more in postoperative work-up of MTC. Alternatively, F-fluorodeoxyglucose and other positron emission tomography radiopharmaceuticals such as F-fluorodopa or F-fluorodopamine as well as radiolabelled antibodies such as Tc/I/I anticarcinoembryonic antigen, antigastrin, and anticholecystokinin-B have promising results. Functional imaging has a great advantage for nuclear medicine techniques in the routine work-up of MTC patients and also has a wide use in experimental studies.

Routine serum calcitonin measurement in the evaluation of thyroid nodules

Calcitonin (CT) is secreted mainly by parafollicular C cells. In normal subjects, serum CT (sCT) levels are low and barely detectable by commonly used assays. Increased sCT levels are highly suggestive of medullary thyroid carcinoma (MTC). Since the clinical manifestation of MTC is a thyroid nodule, either single or in the context of a multinodular goitre, the routine measurement of sCT in the evaluation of thyroid nodule(s) facilitates the diagnosis of MTC. sCT measurement is indeed more sensitive than cytology in finding MTC. There are two major benefits from this clinical practice: (a) the surgeon is alerted to the need to perform total thyroidectomy and central compartment lymphadenectomy, which is the minimal surgical treatment for MTC; and (b) the outcome of MTC is favourably affected because it is usually identified at a less advanced stage. However, other non-MTC causes of hypercalcitoninaemia and false sCT positivity do exist and must be recognized. The differential diagnosis is possible using previously validated assays against possible sources of interference, and performing stimulation tests with pentagastrin or, eventually, calcium infusion.

Calcitonin measurement in the evaluation of thyroid nodules in the United States: a cost-effectiveness and decision analysis

CONTEXT

European studies have shown that the use of routine calcitonin screening for detection of medullary thyroid cancer (MTC) in patients with thyroid nodules increases the detection of occult MTC and may improve patient outcomes. Calcitonin screening for MTC has not been recommended in recent U.S. practice guidelines.

OBJECTIVE

Our objective was to determine the cost-effectiveness (C/E) of routine calcitonin screening in adult patients with thyroid nodules in the United States.

SETTINGS/SUBJECTS

A decision model was developed for a hypothetical group of adult patients presenting for evaluation of thyroid nodules in the United States. Patients were screened using current American Thyroid Association guidelines only, or American Thyroid Association guidelines with routine serum calcitonin screening. Input data were obtained from the literature, the Surveillance Epidemiology and End Results and Healthcare Cost and Utilization Project's Nationwide Inpatient Sample databases, and the Medicare Reimbursement Schedule. Sensitivity analyses were performed for a number of input variables.

MAIN OUTCOME MEASURES

C/E, measured in dollars per life years saved (LYS), was calculated.

RESULTS

Addition of calcitonin screening to current American Thyroid Association guidelines for the evaluation of thyroid nodules would cost $11,793 per LYS ($10,941-$12,646). When extrapolated to the national level, calcitonin screening for MTC in the United States would yield an additional 113,000 life years at a cost increase of 5.3%. Calcitonin screening C/E is sensitive to patient age and gender, and to changes in disease prevalence, specificity of fine needle aspiration and calcitonin testing, calcitonin screening level, costs of testing, and length of follow-up.

CONCLUSION

Routine serum calcitonin screening in patients undergoing evaluation for thyroid nodules appears to be cost effective in the United States, with C/E comparable to the measurement of thyroid stimulating hormone, colonoscopy, and mammography screening.

An unusual succinate dehydrogenase gene mutation C in a case of laryngeal paraganglioma

Objective:

To report a rare case of a laryngeal paraganglioma related to succinate dehydrogenase gene mutation C.

Method:

A case report and a review of the world literature concerning succinate dehydrogenase mutations and laryngeal paraganglioma are presented.

Results:

We identified a laryngeal paraganglioma in a 38-year-old woman, related to a very rare, deleterious in exon 4 of the succinate dehydrogenase mutation C. This mutation was a non-sense mutation: c.183G >A leading to p.Trp61X. No other neuroendocrine tumour was identified in this case, but a thyroid papillary carcinoma was concomitantly discovered and cured.

Conclusion:

To our knowledge, this is the first report in the world literature of laryngeal paraganglioma related to a succinate dehydrogenase mutation C. The case presented underlines the fact that every patient with paraganglioma should be tested for succinate dehydrogenase genetic mutations, even if a family history of paraganglioma is absent, in order to enable appropriate clinical management and to improve our knowledge of familial paraganglioma.

Cancer médullaire de la thyroïde

Medullary thyroid carcinoma (MTC) is developed from thyroid C cells that secrete calcitonin (CT). MTC represents 5-10% of thyroid cancers with a 1-2% incidence in nodular thyroid diseases. Diagnosis is usually made by a solitary nodule often associated to nodal metastasis and confirmed by a high basal CT level which represents its biological marker. MTC may present as a sporadic form and in about 30% of case as a familial form as a part of multiple endocrine neoplasia syndrome, an hereditary dominant inherited disease related to germline mutation of the proto-oncogene RET. Both biological (CT) and genetic (RET) markers allows the optimal diagnosis and treatment of MTC; the former allows screening and early diagnosis of MTC by routinely CT measurements in nodular thyroid diseases that make the adequate and complete surgery required to be performed. The former leads to diagnose familial MTC and to identify at risk subjects in whom early or prophylactic surgery may be performed. Treatment of MTC is based on the complete surgical resection: total thyroidectomy associated to central and laterocervical nodal dissection. For locally advanced or metastatic MTC, complete cervical surgery is required and needs to be associated to other systemic treatments: as chemotherapy is not very efficient, radioimmunotherapy and RET target gene therapy (mainly tyrosine kinase inhibitors) appears as possible valuable therapeutic options for the future. Prognosis of MTC is mainly related to both the stage of the disease and the extend of the initial surgery. Ten-year survival is about 80% when the patients are not surgically cured and reaches 95% when the biological marker CT is normalized after surgery.

Evidence-based approach to the management of sporadic medullary thyroid carcinoma

Medullary thyroid carcinoma (MTC) is a rare malignancy of the thyroid C cells. It occurs in hereditary (25% of cases) and sporadic (75%) forms. Sporadic MTCs frequently metastasize to cervical lymph nodes. Thorough surgical extirpation of the primary tumor and nodal metastases by compartment-oriented resection has been the mainstay of treatment (level IV evidence). Surgical resection of residual and recurrent disease is effective in reducing calcitonin levels and controlling complications of central neck disease (level IV evidence). Radioactive iodine, external beam radiation therapy, and conventional chemotherapy have not been effective. Newer systemic treatments, with agents that target abnormal RET proteins hold promise and are being tested in clinical trials for patients with metastatic disease.

Predictive value of serum calcitonin levels for preoperative diagnosis of medullary thyroid carcinoma in a cohort of 5817 consecutive patients with thyroid nodules

CONTEXT

Routine serum calcitonin (CT) measurement in patients with thyroid nodules for diagnosis of medullary thyroid carcinoma (MTC) is controversial.

OBJECTIVE

The objective of this study was to evaluate the diagnostic accuracy of systematic CT measurement in non-multiple endocrine neoplasia type 2 patients with nodular thyroid disease.

SETTINGS

This study was conducted at a national healthcare system hospital (outpatient and inpatient sectors).

SUBJECTS

Consecutive patients with nodular thyroid disease (n = 5817) were studied.

MAIN OUTCOME MEASURES

Serum CT levels were measured under basal conditions, and when basal values were more than or equal to 20 and less than 100 pg/ml, testing was repeated after pentagastrin stimulation. Basal or stimulated levels more than 100 pg/ml were indication for surgery.

RESULTS

Fifteen cases of MTC and seven of C cell hyperplasia (CCH) were identified. MTCs were diagnosed in all patients with basal CT more than 100 pg/ml. The four patients with basal CT more than or equal to 50 and less than 100 pg/ml included two diagnosed with MTC and two with CCH. In 10 patients with basal levels more than or equal to 20 and less than 50 pg/ml, histology confirmed the presence of MTC in four, four others had CCH, and the remaining two were negative for thyroid malignancy. Positive predictive values for basal CT levels in the preoperative diagnosis of MTC were: 23.1% for values more than or equal to 20 pg/ml, 100% for values more than 100 pg/ml, 25% for levels more than or equal to 50 and less than 100 pg/ml, and 8.3% for values more than or equal to 20 and less than 50 pg/ml. Positive predictive values for the pentagastrin test (>100 pg/ml) were 40% in the entire series.

CONCLUSIONS

CT screening of thyroid nodules is a highly sensitive test for early diagnosis of MTC, but confirmatory stimulation testing is necessary in most cases to identify true positive increases.

Measurement of calcitonin by immunoassay analyzers

BACKGROUND

Since Nichols Institute Diagnostics (NID) ended production of their automated calcitonin immunoassay, evaluation of an alternative calcitonin assay was necessary.

METHODS

Calcitonin measured by the NID procedure was compared with a test from Diagnostic Products Corporation (DPC). Calcitonin was also measured by assays from DiaSorin (DS) and Scantibodies (SC).

RESULTS

In 187 samples, detection failed either by NID (39%) or DPC (96%) assay; in 35% of samples, the tests agreed for non-measurable calcitonin. The regression line DPC=0.78 x NID-0.3 (r=0.998) fitted results from 236 samples with detectable calcitonin. A linear relationship, albeit with scattering at low concentrations, was observed. Importantly, stimulation by pentagastrin above basal calcitonin concentrations yielded similar results with both assays. Comparisons (DPC=0.80 x DS-3.4 and DPC=0.81 x SC-1.1) confirmed an aberrant calibration of the DPC test. To overcome the method bias, we propose a multiplication factor of 0.8 to convert NID to DPC results.

CONCLUSIONS

Apparently due to non-specific effects, the DS and SC assays produced calcitonin results in samples from completely thyroidectomized patients, while the DPC assay correctly failed to detect calcitonin. Thus, the DPC assay on an Immulite 2000 analyzer may be used as a more accurate substitute for NID if the different calibration is noted.

Serum calcitonin negative medullary thyroid carcinoma

Background

Medullary thyroid carcinomas (MTC) constitute about 5 to 7 % of thyroid neoplasms. They originate from parafollicular C cells which produce Calcitonin, a hormone which has an impact on calcium metabolism and represents the biochemical activity of MTC. In rare cases pre-operative serum calcitonin can be negative.

Case presentation

We report on a 73-year-old female patient with a rare case of a serum calcitonin negative medullary thyroid carcinoma who suffered fulminant post-operative course and died of multiple metastasis.

Conclusion

This case shows that in very rare cases MTCs do not secrete calcitonin making diagnosis and tumour follow-up difficult. To this date, only few reports describing this combination of circumstances were found in the English literature.

Comment interpréter une hypercalcitoninémie ?

PURPOSE

Today, calcitonin assay is used for the diagnosis of thyroid medullary cancer in the context of nodular thyroid disease. Calcitonin is an excellent marker of thyroid medullary cancer but some hypercalcitoninemia can also be related to other diseases, such as renal failure, endocrine tumors other than thyroid medullary cancer and sometimes to C cell hyperplasia, which is a not well-defined situation. Recent studies contributed to define calcitoninemia thresholds, which guide decision and avoid excessive invasive treatment.

CURRENT KNOWLEDGE AND KEY POINTS

After a brief reminder of physiological role of calcitonin and assays, the difficulties encountered in interpreting hypercalcitoninemia and its potential causes other than thyroid medullary cancer are addressed. Recent studies, on large series, now allow a better knowledge of specificity and sensitivity of calcitonin measurement in patients with nodular thyroid disease and a well-argued management.

FUTURE PROSPECTS AND PROJECTS

In the future, calcitonin dosage will be ordered even more frequently, as some authors recommend it for the diagnosis of thyroid nodule. It is up to us to know how to use this remarkable marker, by considering all possible situations of benign hypercalcitoninemia and reserving aggressive treatments for patients who really need them.

Value of routine measurement of serum calcitonin concentrations in patients with nodular thyroid disease: A multicenter study

BACKGROUND

The routine measurement of serum calcitonin (CT) has been proposed for patients with nodular thyroid disease (NTD), to detect unsuspected medullary thyroid carcinoma (MTC) before surgery.

OBJECTIVE

To assess the prevalence of hypercalcitoninemia and MTC in NTD patients; to compare the ability of CT measurement and fine needle aspiration cytology (FNAC) to predict MTC; to identify age groups of NTD patients who should be better candidates than others to undergo routine measurement of CT.

PATIENTS AND METHODS

1425 consecutive patients, referred from April 1, 2003, through March 31, 2004, to four Italian endocrine centers due to NTD, were grouped depending on age, and underwent basal and, in some cases, pentagastrin (Pg)-stimulated CT measurement, FNAC and, when indicated, surgery. Serum CT concentrations were measured by an immunoluminometric assay (ILMA).

RESULTS

Hypercalcitoninemia was found in 23 out of 1425 patients. MTC was discovered in 9 patients, all >40 yr old and showing high CT levels. Sensitivity of basal and Pg-stimulated CT to predict MTC before surgery was 100% for both tests, whereas specificity was 95 and 93%, respectively. CT specificity reached 100% when a cutoff value of 20 pg/ml was taken. FNAC showed an overall 86% sensitivity. When >10 mm MTC nodules were considered, FNAC sensitivity approached 100%. On the contrary, a correct cytological diagnosis was obtained in only one out of five patients with <10 mm MTC nodules (microMTC); in one patient with histologically proved microMTC, FNAC even demonstrated a benign lesion. Hypercalcitoninemia or MTC were associated with chronic thyroiditis in 30 or 33% of cases, respectively. C-cell hyperplasia was found in 57% of hypercalcitoninemic patients without MTC.

CONCLUSIONS

Basal CT measurement detects elevated CT values in 1.6% of NTD patients. Although CT is not a specific marker of MTC, its routine measurement represents a useful tool in the pre-operative evaluation of NTD patients, particularly those >40 yr old presenting with nodules <10 mm, even when FNAC does not show malignant features. To our knowledge, this is the first trial using ILMA to assess the ability of pre-operative CT measurement to predict MTC in a large series of NTD patients.

Isthmus-Preserving Total Bilobectomy: An Adequate Operation for C-Cell Hyperplasia

BACKGROUND

Autopsy studies show that C cells deriving from the ultimobranchial body and migrating into the thyroid do not reach the isthmus region and are distributed along the vertical axes of thyroid lobes. This was confirmed in a surgical series of 58 patients (34 with preoperatively normal and 24 with elevated serum calcitonin) where no calcitonin-positive cells were demonstrable immunohistochemically within separately investigated isthmi. Consequently, isthmus-preserving total bilateral lobectomy (IPTB) may be regarded as an adequate surgical procedure for C-cell hyperplasia (CCH).

PATIENTS AND METHODS

IPTB was performed from October 2001 to December 2004 in 64 patients, 59 patients with nodular goiter and slightly to moderately elevated serum calcitonin (stimulated under 500 pg/ml) (group A, apparently sporadic cases) and in 5 patients undergoing prophylactic surgery for hereditary medullary thyroid carcinoma (MTC) with intermediate- or low-risk RET mutations (non-634) (group B). The surgical procedure focused on meticulous total extracapsular resection of both thyroid lobes, preservation of an isthmus remnant of about 3 ml (smaller in children), and histologic workup of the border zones of resection in addition to that of the completely removed lobes. When malignancy could be proven intraoperatively (7 patients) or when the isthmus turned out to contain nodular lesions (4 patients), completion total thyroidectomy (plus lymphadenectomy) was performed as a one-stage procedure. Second-stage total thyroidectomy was performed in 3 cases. Thus, IPTB was the definitive surgical procedure in 50 patients (45 of group A and all 5 of group B).

RESULTS

In all of the 50 definite IPTB cases, postoperative serum calcitonin was below the measurable limit (2 pg/ml); stimulated calcitonin was below the measurable limit in 47 (including all of group B) and was measurable in 3 sporadic cases in a lower-normal range between 2.4 and 3.5 pg/ml. Genetic screening of the apparently sporadic cases with CCH was positive in one (codon 791). The risk of recurrent laryngeal nerve paralysis seems not to be elevated (0% permanent); permanent hypocalcemia occurred in 1 patient (2%). Follow-up data of 37 patients, median 18 (6-36) months, showed continuously nonmeasurable serum calcitonin with one exception, where it was in the normal range after 18 months. All IPTB patients are still under substitution therapy with L-thyroxine (median 125 mug/day) with decreasing tendency in all 3 children after prophylactic operation, the latter also showing an increasing volume of well-vascularized isthmi (from 1.5 to 2.5 ml).

CONCLUSION

IPTB reliably removes all C cells. There may not be need for total thyroidectomy (TTx) in cases with CCH. When necessary, completion TTx can be performed easily without additional risk. IPTB leaves a functionally relevant remnant, corresponding to that of a subtotal resection. This might be of importance especially for prophylactic surgery in children where the isthmus can compensate for the loss of thyroid function with time.

Early diagnosis and curative therapy of medullary thyroid carcinoma by routine measurement of serum calcitonin in patients with thyroid disorders

To identify patients with medullary thyroid carcinoma (MTC) at a potentially curable stage of the disease, serum concentrations of calcitonin (hCT) were determined in 14,000 patients (including 10,158 patients with thyroid nodules) referred to a thyroid outpatient clinic. Excluding patients in whom elevated basal hCT concentrations had already been known at the time of their referral, 507 patients with thyroid nodules presented basal concentrations of hCT of more than 10 pg/ml. Following stimulation by IV pentagastrin (0.5 microg/kg BW), hCT concentrations of more than 100 pg/ml were seen in 103 patients. This group included 32 new cases of MTC (29 patients with sporadic MTC and 3 new index cases of the familial form) and 43 patients with C cell hyperplasia (CCH). Among the 3,843 patients without thyroid nodules, 2 were found to harbor sporadic MTC while 4 had CCH. As compared to 1.1 cases of MTC per 1,000 patients with nodular thyroid diseases diagnosed in our institution before hCT screening was begun, 3.2 cases of MTC per 1,000 patients were identified when hCT was determined in all patients with thyroid nodules. The determination of hCT in all patients with thyroid nodular disease facilitates the timely diagnosis of MTC, thus providing the chance of curative surgery.

Preoperative diagnosis of medullary thyroid carcinoma: fine needle aspiration cytology as compared with serum calcitonin measurement

BACKGROUND AND OBJECTIVES

Preoperative diagnosis of sporadic medullary thyroid carcinoma (MTC) has mainly relied on fine needle aspiration cytology (FNAC). The present study aimed to compare the sensitivity of this technique with serum calcitonin (CT) measurement and to assess the therapeutic implications of an inadequate preoperative diagnosis.

METHODS

We reviewed the clinical records of 91 MTC patients treated and/or followed at our institution between January 1990 and December 2003.

RESULTS

After revision of clinical records, 77 individuals were considered eligible for the study. FNAC was performed in 67 patients (87%) with a sensitivity of 63%; serum CT was measured in 56 patients (73%) with a sensitivity of 98%. Both FNAC and serum CT were assessed in 51 patients (66%). FNAC detected only 74.5% of MTCs suspected by elevated serum CT. Among patients with a cytological diagnosis of MTC, total thyroidectomy (TT) was performed in 95% of patients. Among patients without a cytological diagnosis of MTC, TT was performed in 83% of patients in whom serum CT was evaluated prior to surgery whereas it was performed in only 46% of patients in whom CT evaluation was lacking.

CONCLUSIONS

Despite the higher sensitivity of serum CT measurement, as compared with FNAC to diagnose MTC (98% vs. 63%), only 9% of patients might have escaped to surgery based on FNAC results. However, indication for surgery based on suspicious FNAC may not alert the surgeon for the need of a TT and exploration of nodes at least in the central compartment.

Increased calcitonin level in thyroid nodules without medullary carcinoma

Background

Basal calcitonin measurement is routinely performed in patients with a thyroid nodule to detect medullary carcinoma. However, increased calcitonin does not always correlate with medullary carcinoma. The aim of this study was to analyse increased calcitonin levels in patients without medullary carcinoma and to find out whether absence of this carcinoma can be predicted with certainty.

Methods

From 1992 to 2003, 5018 patients with thyroid nodules underwent thyroid surgery. A retrospective analysis of preoperative increased calcitonin levels in 67 of these patients was performed.

Results

Pathology revealed medullary carcinoma in 16 patients (group I), micromedullary carcinoma in 13 (group II) and no medullary carcinoma in 38 (group III). In group III, 30 patients had C-cell hyperplasia. The mean basal calcitonin level was 6250 pg/ml in group I (39–62 500), 109·6 pg/ml in group II (10–728) and 25·5 pg/ml in group III (10·5–145). The mean pentagastrin-stimulated calcitonin level was 1074·1 pg/ml in group II (26–5700) and 67·6 pg/ml in group III (10–205).

Conclusion

There is an overlap of thyroid C-cell pathology for medullary carcinoma, micromedullary carcinoma and C-cell hyperplasia that occurs when basal calcitonin is between 10 and 145 pg/ml and pentagastrin-stimulated calcitonin between 10 and 205 pg/ml. In these patients, since medullary carcinoma cannot be completely excluded, total thyroidectomy should be recommended.