Basal Calcitonin Levels Research Articles

Biomarker-Based Risk Stratification for Previously Untreated Medullary Thyroid Cancer

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. 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. This was a retrospective analysis. The setting was a tertiary referral center. Included were 300 consecutive patients with previously untreated MTC. The intervention was compartment-oriented surgery. Stratified biomarker levels were correlated with histopathologic extent of disease. 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. 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.

Clinicopathological Characteristics and Prognostic Factors of Medullary Thyroid Carcinoma

Background: Studies on the clinicopathological characteristics and prognostic factors of medullary thyroid carcinoma (MTC) in Korea are very rare. Methods: We enrolled 56 MTC patients who underwent surgery at Samsung Medical Center from 1995 to 2006. We analyzed their gender, age at diagnosis, the pathologic findings, the TNM stage, the association with multiple endocrine neoplasia (MEN), RET protooncogene mutation and the, serum basal calcitonin levels before and after the surgery. We investigated the overall survival and the prognostic factors. Results: The mean age at diagnosis was 46 years and the male/female ratio was 1:2.7. Fine needle aspiration cytology detected 61% of the MTC. The mean tumor size was 2.6 cm (range: 0.2-9.0 cm). Fifty-two percent of patients had the TNM stage more than III at the time of diagnosis. Distant metastasis was found in 5.3% (3/56) of the patients, either at the time of diagnosis or during the followup period. Hereditary MTC comprised of 23% of the patients and the disease developed at a younger age (38 years vs. 48 years, respectively, P

Importance of gender-specific calcitonin thresholds in screening for occult sporadic medullary thyroid cancer

Men and women differ in thyroidal C-cell mass and calcitonin secretion. This difference may have implications for the definition of calcitonin thresholds to distinguish sporadic C-cell hyperplasia from occult medullary thyroid cancer. This retrospective study examined the hypothesis that gender-specific calcitonin thresholds predict occult medullary thyroid cancer more accurately among patients with increased basal calcitonin levels than unisex thresholds. A total of 100 consecutive patients were evaluated with occult sporadic C-cell disease no larger than 10 mm who were referred for increased basal calcitonin levels and underwent pentagastrin stimulation preoperatively at this institution. Altogether, gender-specific calcitonin thresholds predicted medullary thyroid cancer better than unisex thresholds. At lower (<or=50 pg/ml basally; <or=500 pg/ml after stimulation), but not higher, calcitonin serum levels, women revealed medullary thyroid cancer four to eight times more often than men. Most discriminatory between C-cell hyperplasia and medullary thyroid cancer was a basal calcitonin threshold of 15 pg/ml (corrected 20 pg/ml) for women and 80 pg/ml (corrected 100 pg/ml) for men, based on the greatest accuracy at the lowest possible calcitonin level. The respective gender-specific stimulated peak calcitonin thresholds were 80 pg/ml (corrected 100 pg/ml) and 500 pg/ml. Corresponding positive predictive values for medullary thyroid cancer at these calcitonin thresholds were 89 and 90% for women, as opposed to 100% for men. To increase the positive predictive value for women to 100%, the respective calcitonin thresholds would have to be raised to 40 pg/ml (corrected 50 pg/ml) and 250 pg/ml. These findings indicate that gender-specific calcitonin thresholds predict sporadic occult medullary thyroid cancer better than unisex thresholds.

Individualization of Lymph Node Dissection in RET (Rearranged During Transfection) Carriers at Risk for Medullary Thyroid Cancer

This study sought to define the need for lymph node dissection in Rearranged during Transfection (RET) carriers at risk for hereditary medullary thyroid cancer. Controversy surrounds the need for lymph node dissection to complement thyroidectomy in RET carriers. Integration of molecular, biochemical, histopathologic, and clinical information from 308 RET carriers referred for (re-)operation to a specialist surgical center. The carriers differed significantly in age at thyroidectomy when stratified by histopathology (tumor-free thyroid, node-negative, and node-positive medullary thyroid cancer) and mutated codon (611, 618, 620, 634, 768, 790, 804, 891, and 918). The wide overlap among the 3 histopathologic groups compromised individual predictions based on age alone. There was a significant relationship between the presence of lymph node metastases and increased pretherapeutic basal calcitonin levels. All 46 carriers with node-positive medullary thyroid cancer, who harbored 1 to 68 positive nodes, exhibited increased pretherapeutic basal calcitonin levels (91.4 pg/mL or higher). Conversely, 74 (44%) of 168 carriers with normal thyroids, C-cell hyperplasia, or node-negative medullary thyroid cancer displayed normal pretherapeutic basal calcitonin levels (negative predictive value 100%). Prediction of lymph node metastasis was better in carriers of codon 918 mutations (positive predictive value, PPV, 80%-100%) and those older than 20 years of age (PPV, 50%). In the absence of clinical evidence to the contrary, RET carriers with normal pretherapeutic basal calcitonin levels may forgo lymph node dissection. The usefulness of calcitonin thresholds to break down the block of carriers with increased calcitonin levels should be explored further.

Effect of calcium loading test on calcitonin and katacalcin levels before and after surgical removal of the ovaries.

Since the role of gonadal steroids and their interrelation with calcium regulating hormones is not clear, we performed a prospective study to investigate the effects of gonadectomy on the calcitonin (CT)/katacalcin (KT) system using 1 minute calcium infusion as a provocative test. Seventeen women aged 26-51 years awaiting abdominal hysterectomy with bilateral oophorectomy were included in the study and the same protocol was repeated 14 days after surgery. CT and KT concentrations were determined radioimmunologically after reverse phase extraction of serum, thus predominantly measuring monomeric CT and KT. The same protocol was repeated 14 days after surgery. Removal of the gonads in reproductive age did not alter basal or peak CT levels (9.7 +/- 0.8 vs. 8.9 +/- 0.7 ng/l and 13.4 +/- 1.6 vs. 12.7 +/- 1.2 ng/l) or KT levels (3.2 +/- 1.8 vs. 3.9 +/- 2.2 ng/l basal and 4.1 +/- 2.6 vs. 5.4 +/- 2.8 ng/l peak). Although not statistically different at any individual point, the shapes of the curves were significantly altered after surgery, indicating changes in the metabolism of CT and KT. These results support the hypothesis that CT and possibly KT play a role in the change of calcium metabolism coinciding with the oestrogen withdrawal at the menopause.

Medullary thyroid carcinoma and biomarkers: past, present and future

The clinical management of patients with persistent or recurrent medullary thyroid carcinoma (MTC) is still under debate, because these patients either have a long-term survival, due to an indolent course of the disease, or develop rapidly progressing disease leading to death from distant metastases. At this moment, it cannot be predicted what will happen within most individual cases. Biomarkers, indicators which can be measured objectively, can be helpful in MTC diagnosis, molecular imaging and treatment, and/or identification of MTC progression. Several MTC biomarkers are already implemented in the daily management of MTC patients. More research is being aimed at the improvement of molecular imaging techniques and the development of molecular systemic therapies. Recent discoveries, like the prognostic value of plasma calcitonin and carcino-embryonic antigen doubling-time and the presence of somatic RET mutations in MTC tissue, may be useful tools in clinical decision making in the future. In this review, we provide an overview of different MTC biomarkers and their applications in the clinical management of MTC patients.

Constitutive RET tyrosine kinase activation in hereditary medullary thyroid cancer: clinical opportunities

The ground-breaking discovery of genotype-phenotype relationships in hereditary medullary thyroid cancer has greatly facilitated early prophylactic thyroidectomy. Its timing depends not solely on a positive gene test but, more importantly, on the type of the REarranged during Transfection (RET) mutation and its underlying mode of RET receptor tyrosine kinase activation. In the past decade, the therapeutic corridor opened by molecular information has been defined down to a remarkable level of detail. Based on mutational risk profiles, preemptive thyroidectomy is recommended at 6 months of age for carriers of highest-risk mutations, before the age of 5 years for carriers of high-risk mutations, and before the age of 5 or 10 years for carriers of least-high-risk mutations. Additional lymph node dissection may not be needed in the absence of increased preoperative basal calcitonin levels. Better comprehension of RET function should enable the design of targeted therapies for RET carriers beyond surgical cure in whom the DNA-based 'window of opportunity' has been missed.

When Is Prophylactic Thyroidectomy Indicated for Patients with the RET Codon 609 Mutation?

Mutations in the RET proto-oncogene cause multiple endocrine neoplasia type 2A (MEN2A), and prophylactic thyroidectomy has generally been recommended before the age of 5 years. Patients with codon 609 mutations develop MTC at a later age and therefore the timing of prophylactic thyroidectomy is less clear. We report a three-generation family with C609Y RET mutation where members having prophylactic or therapeutic thyroidectomy call the current recommendations for age at thyroidectomy into question. Sixteen family members underwent thyroidectomy, for which clinical, laboratory, and pathological data were analyzed. A literature review of RET codon 609 mutations was carried out. Data were collected from 16 patients from this 38-member kindred. None of these affected members had pheochromocytoma, and one had a parathyroid adenoma. Nine of 16 patients had MTC (mean age 44.7 years, range 29-59 years) and elevated basal calcitonin levels; 6 of these 9 had lymph node metastases. Two patients had C-cell hyperplasia (CCH) at ages 18 and 37 years, and five patients had normal thyroid pathology (mean age 16 years, range 5-37 years). In the literature, a family with C609Y mutation was reported, with 15 members having MTC (mean age 42 years, range 21-59 years), and 6 with CCH (mean age 24 years, range 15-37 years). The youngest patient with C609Y RET mutation and MTC was 21 years old, and the youngest patient with CCH was 15 years old at diagnosis. These data suggest that patients with RET C609Y mutations can delay thyroidectomy until 10-15 years of age, with annual calcitonin screening prior to thyroidectomy.

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.

Clinical and Oncological Features of Children and Young Adults with Multiple Endocrine Neoplasia Type 2A

RET genotype analysis allows identification of asymptomatic carriers at risk of developing medullary thyroid carcinoma (MTC). However, there is still controversy regarding the ideal timing and extent of prophylactic thyroidectomy due to the wide spectrum of clinical presentation. Surveillance of a large number of young patients is crucial to advance our understanding of the natural course of the disease. This study aimed to describe the clinical presentation, oncological features, and treatment outcome of children and young adults harboring RET mutations followed at our institution from 1997 to 2007. Forty-one individuals aged < or =25 years from 17 independent multiple endocrine neoplasia type 2A kindred were studied. Twenty-one individuals presented with thyroid nodules at diagnosis, and 20 were disease free at physical examination. Preoperative basal calcitonin levels were elevated in 85.7% of patients with clinical disease and in 54.5% of asymptomatic carriers. Thyroid ultrasonography (US) showed one or more nodules in 69.0% of the patients. A positive correlation between age at surgery and tumor-node-metastasis (TNM) stages was observed (p < 0.001). None of the patients under 15 years of age presented lymph node or distant metastasis. After a follow-up of 4.4 +/- 1.4 years all asymptomatic patients were disease free based on physical examination, cervical US, and undetectable serum calcitonin levels. In the group of patients with clinical disease, 47.6% have persistent disease (follow-up of 12.0 +/- 5.9 years). Indeed, palpable thyroid nodule at diagnosis was significantly associated with persistent disease (p < 0.001, odds ratio [OR] 1.9, 95% confidence interval [CI 95%] 1.27-2.87). Of note, none of the patients who presented lymph node metastasis at diagnosis were cured by surgical intervention (p < 0.001, OR 5.0, CI 95% 1.45-17.0). Our data show a time-dependent MTC progression. The presence of a palpable thyroid nodule and lymph node metastasis at diagnosis was associated with persistent or recurrent disease after surgical procedure.

Does the RET variant G691S influence the features of sporadic medullary thyroid carcinoma?

The RET (rearranged during transfection) proto-oncogene G691S variant is over-represented in the germline of patients with sporadic medullary thyroid carcinoma (sMTC) vs. normal controls but so far is not associated with any medical or pathological features of the tumour. The aim of our study was to assess the influence of this variant on the age of onset, clinical, biological and pathological features of sMTC. One hundred patients with histologically proven MTC, for whom the germline genetic analysis of RET was negative and medical records were available, were included in the study. Patients with the heterozygous GS variant or the homozygous SS variant (n = 36) were on average 8.0 years younger than patients with the wild-type GG variant (n = 64, mean age 43.9 vs. 51.9 years, P < 0.01). The former group did not differ from the wild-type group in terms of MTC size, prevalence of C-cell hyperplasia (CCH) or papillary thyroid carcinoma (PTC). However, the prevalence of an increased preoperative basal calcitonin (bCT) level (> 1000 pg/ml) was 2.75-fold higher in the patients with the GS or SS variant than in those with the wild-type variant (P < 0.001). The proportion of patients with lymph node metastases was also higher in the former group (P < 0.05). Multivariate analysis confirmed that the presence of the RET variant is independently associated with higher preoperative bCT values (P = 0.011). Our data demonstrate that the RET G691S variant could modulate the age of onset of sMTC as demonstrated previously for familial tumours. Moreover, this variant is an independent predictor of a higher basal calcitonin synthesis rate in patients with sMTC.

Difference in development of medullary thyroid carcinoma among carriers of RET mutations in codons 790 and 791*

Hereditary medullary thyroid carcinoma (MTC) is caused by germ-line mutations in the RET proto-oncogene. Our study addresses the difference in development of MTC between rare mutations in RET codons 790, 791 and 804. We evaluated tumour stage, calcitonin levels, biochemical cure rates and associated endocrinopathies in 153 German/Austrian patients with RET 790 (n = 47), 791 (n = 56) and 804 mutations (n = 50), divided into index- and screening groups. Age at diagnosis in index-patients did not differ significantly among the three codon groups (medians of 57, 61 and 53 years). Tumour stage at diagnosis was significantly less advanced with codon 791 (n = 22) than 790 (n = 16) and 804 (n = 16) mutations (P = 0.001). In screening patients, age at diagnosis did not differ significantly among the three groups (medians 19, 24 and 32 years). Tumour stage at diagnosis was also significantly less advanced with codon 791 (n = 34) than 790 (n = 31) and 804 (n = 34) (P = 0.032). Preoperative basal calcitonin levels were significantly lower in codon 791 carriers compared to codon 790 carriers, and cure rates were significantly higher in both index (75%vs. 31%; P = 0.03) and screening patients (100%vs. 75%; P = 0.015). Additional endocrinopathies were observed only with codon 791 carriers (four pheochromocytomas and two hyperparathyroidism). There is a significant difference in MTC development with less extensive C-cell disease, higher cure rate and more frequent additional endocrinopathies in carriers of RET codon 791 mutations compared with carriers of codons 790 and 804 mutations. This information should be considered when age of prophylactic thyroidectomy is discussed.

Medullary Thyroid Cancer Responsiveness to Pentagastrin Stimulation: An Early Surrogate Parameter of Tumor Dissemination?

Because of its outstanding sensitivity, stimulation of calcitonin secretion with iv injection of pentagastrin is widely used for biochemical diagnosis of medullary thyroid cancer. The objective of this study was to explore the relationship between the results of the pentagastrin stimulation test and extent of disease in patients with previously untreated medullary thyroid cancer. This was a retrospective study. The investigation took place at a tertiary referral center. Included were 89 patients with increased basal calcitonin levels who had a pentagastrin test at this institution before initial neck surgery for medullary thyroid cancer. Measurements included basal and stimulated calcitonin levels, carcinoembryonic antigen levels, primary tumor diameter, extrathyroidal extension, lymph node metastases, and distant metastases. There was a strong dose-dependent relationship between a less than 10-fold increase in preoperative calcitonin levels after iv stimulation with pentagastrin and both the frequency (41-54 vs. 4-27%; P = 0.001) and number (means of 3.0-10.8 vs. 0-1.1 positive nodes, P < 0.001) of lymph node metastases. Weaker associations were identified with the respective frequency of extrathyroidal extension (14-27 vs. 0-7%; P = 0.027), distant metastasis (9-23 vs. 0%; P = 0.017), and postoperative normalization of calcitonin (40-55 vs. 53-82%; P = 0.029). On multivariate analysis, only lymph node metastases were associated with a less than 10-fold increase in preoperative calcitonin levels. Based on these clinical data and preclinical literature, reduced responsiveness to stimulation with pentagastrin may reflect early dedifferentiation. Evidence of this condition may enable early risk stratification in patients with medullary thyroid cancer.

Multi-modality imaging of uveal melanomas using combined PET/CT, high-resolution PET and MR imaging

In spite of the fact that the German Society of Endocrinology has recommended calcitonin as screening-parameter the majority of physicians in Germany do not routinely use calcitonin in patients with thyroid nodules to exclude medullary thyroid cancer (MTC). The future revision of the recommendation should describe reference values for each commercially available assay, separately for men and women (basal and after pentagastrin-stimulation), and should define sonomorphological inclusion criteria. The epidemiological database of the prevalence of MTC is controversial and the specificity of basal elevated calcitonin levels is limited up to the 5-fold of the upper reference level. If renal insufficiency, bacterial infection, and an alcohol- or drug-induced stimulation of calcitonin is excluded, hypercalcitoninaemia should be confirmed by a second measurement (if necessary using another assay). Stimulation of calcitonin by use of pentagastrin is mandatory prior to the decision on thyroidectomy. A stimulated calcitonin level < 100 pg/ml justifies "wait and see". If stimulated calcitonin levels range between 100 and 200 pg/ml or higher, the differentiation between C-cell hyperplasia and MTC remains uncertain, especially in men. The implementation of calcitonin-screening requires the definition of sonographic inclusion criteria and validation of each assay. Additional pre-requisites are excellent logistic (short period between blood sampling and start of the laboratory test), knowledge of differential diagnoses, knowledge of the consumption of drugs and alcohol, availability of pentagastrin-testing and of moleculargenetic testing with full information to the patients and sufficient time before the decision on surgery is made. All this and the choice of a skilled surgeon, experienced in thyroidectomy and lymphadenectomy with a low rate of local complications are the rationale to recommend calcitonin-screening primarily in centers for thyroid disorders.

Routine measurement of serum calcitonin in patients with nodular thyroid disorders?

SummaryIn spite of the fact that the German Society of Endocrinology has recommended calcitonin as screening-parameter the majority of physicians in Germany do not routinely use calcitonin in patients with thyroid nodules to exclude medullary thyroid cancer (MTC). The future revision of the recommendation should describe reference values for each commercially available assay, separately for men and women (basal and after pentagastrin-stimulation), and should define sonomorphological inclusion criteria. The epidemiological database of the prevalence of MTC is controversial and the specificity of basal elevated calcitonin levels is limited up to the 5-fold of the upper reference level. If renal insufficiency, bacterial infection, and an alcohol- or druginduced stimulation of calcitonin is excluded, hypercalcitoninaemia should be confirmed by a second measurement (if necessary using another assay). Stimulation of calcitonin by use of pentagastrin is mandatory prior to the decision on thyroidectomy. A stimulated calcitonin level &lt;100 pg/ ml justifies “wait and see”. If stimulated calcitonin levels range between 100 and 200 pg/ml or higher, the differentiation between C-cell hyperplasia and MTC remains uncertain, especially in men. The implementation of calcitonin- screening requires the definition of sonographic inclusion criteria and validation of each assay. Additional prerequisites are excellent logistic (short period between blood sampling and start of the laboratory test), knowledge of differential diagnoses, knowledge of the consumption of drugs and alcohol, availability of pentagastrin-testing and of moleculargenetic testing with full information to the patients and sufficient time before the decision on surgery is made. All this and the choice of a skilled surgeon, experienced in thyroidectomy and lymphadenectomy with a low rate of local complications are the rationale to recommend calcitonin-screening primarily in centers for thyroid disorders.

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.

Predictive Value of Serum Calcitonin Levels for Preoperative Diagnosis of Medullary Thyroid Carcinoma in a Cohort of 5817 Consecutive Patients with Thyroid Nodules

Routine serum calcitonin (CT) measurement in patients with thyroid nodules for diagnosis of medullary thyroid carcinoma (MTC) is controversial. 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. This study was conducted at a national healthcare system hospital (outpatient and inpatient sectors). Consecutive patients with nodular thyroid disease (n = 5817) were studied. 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. 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. 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.

Prognostic Significance of Disseminated Tumor Cells in the Connective Tissue of Patients with Medullary Thyroid Carcinoma

Disseminated tumor cells in the connective tissue (CT-DTCs) do not have any connection to a primary tumor or the lymph nodes. They are identified quite often in patients with medullary thyroid carcinoma (MTC), but nothing is known regarding their prognostic significance. Among 450 patients with MTC, 69 (15%) were identified as having CT-DTCs. A case-control group of patients without CT-DTCs was selected. The two groups were matched concerning TNM classification, age, heredity, and sex. Because many patients with CT-DTCs had extrathyroidal tumor extension (pT4 category), distant metastases (M1 category), or both, only 35 matched pairs could be identified. The TNM classification in both groups was as follows: pT1, n = 8; pT2, n = 15; pT3, n = 4; pT4, n = 8; pN0, n = 4; pN1, n = 31; M0, n = 30; M1, n = 5. The mean age was 46.8 +/- 17.0 years in the CT-DTC group and 44.4 +/- 15.0 years in the case-control group (NS). In both groups, 23 patients had sporadic MTC, and 12 patients had hereditary MTC. Neither mean basal preoperative nor postoperative calcitonin levels differed significantly between the two groups. In contrast, none of the patients with CT-DTCs was biochemically cured (normal calcitonin level after pentagastrin stimulation) compared to eight patients without CT-DTCs (P < 0.005). The two groups did not differ concerning other parameters (basal calcitonin level > 3000 pg/ml, more than 10 lymph node metastases, more than two involved locoregional lymph node compartments, mediastinal lymph node metastases) that have been reported to correlate with the lack of or almost (< 10%) lack of biochemical cure. In patients with MTC, disseminated tumor cells in the connective tissue correlate with advanced tumor stages and appear to be of prognostic significance.

Presymptomatic thyroidectomy in multiple endocrine neoplasia 2a

Aims To evaluate the value of prophylactic total thyroidectomy in multiple endocrine neoplasia 2a (MEN 2a), based on results of genetic testing, in a presymptomatic early stage of the disease. Methods Fourteen presymptomatic patients genetically diagnosed and surgically treated at our centre. We analysed age, gender, location of the RET mutation, calcitonin tests, surgery, histologic findings, TNM classification, and postoperative follow-up. Results The 14 patients belonged to two families with MTC (MEN 2a). Median age was 16 years. The RET mutation was located in codon 618 and 634. Basal calcitonin (CT) levels were normal in all patients. Twelve had pathologic peak CT measurements. Total thyroidectomy was performed in all and associated central neck dissection in 12 patients. Pathohistologic assessment showed C-cell hyperplasia in all specimens and 11 MTCs; the median size of the tumours was 0.2 cm; two patient had lymph-node metastases. According to TNM, three had stage 0, nine had stage I, one had stage II, and one had stage III disease. Postsurgery basal and peak CT values were normal in all but one patients, indicating a biochemical curative rate of 95%. Calcitonin determination did not distinguish between MTC and C-cell hyperplasia. Conclusion Prophylactic thyroidectomy based on genetic testing allows identification and treatment of patients at an early stage of the disease. Pathologic peak CT values are markers for the presence of microscopic MTC and should be considered in selecting operative procedures for these patients.

Ghrelin in human medullary thyroid carcinomas

Ghrelin is a novel gastrointestinal hormone involved in several metabolic functions. It has been identified previously in several normal and tumoral neuroendocrine tissues, including human medullary thyroid carcinomas (MTCs). The aim of the study was to evaluate ghrelin levels in patients with MTC and nontoxic goitre (NTG) with elevated calcitonin (CT) levels, as an additional marker of the disease. The study included 22 patients with MTC (four before and 18 after thyroidectomy), 12 patients with NTG with basal CT levels exceeding 10 ng/l and 15 healthy subjects matched for age, sex and body mass index (BMI). After thyroidectomy, MTC patients were considered cured when basal and pentagastrin-stimulated CT levels were < 0.2 and < 10 ng/l, respectively. A pentagastrin-induced CT peak over 50 ng/l was considered as an abnormal response while 100 ng/l was the cut-off accepted for the diagnosis of C-cell hyperplasia or tumour. Circulating ghrelin and CT levels were evaluated at baseline in patients and controls and at -10, 0, 1, 2, 5 and 15 min after pentagastrin injection (0.5 microg/kg body weight) in 12 patients with MTC and nine with NTG. Four surgically removed MTCs were tested for ghrelin expression. Total plasma ghrelin and CT levels were measured with a commercially available radioimmunoassay (RIA) and two-site chemiluminescence immunometric assays, respectively. In paraffin-embedded MTC samples ghrelin immunostaining was performed with a polyclonal antibody (1:1000) and the reaction visualized by an indirect immunoperoxidase system. Plasma ghrelin levels found in cured or not cured MTC and in NTG patients were similar to those of BMI-matched healthy controls. No correlation between ghrelin and CT levels, thyroid disease or previous thyroidectomy was observed. The administration of pentagastrin caused a 17% increase in ghrelin levels (basal ghrelin vs. peak: 162 +/- 62 pmol/l vs. 189 +/- 58 pmol/l, P < 0.05) that was particularly evident (33% increase) in patients with an abnormal CT response to the test (CT > 50 ng/l). Immunohistochemistry showed positivity for ghrelin in a small proportion of CT positive cells from the four MTCs removed. Patients with MTC, NTG and controls showed similar ghrelin levels, ruling out this parameter as a marker of MTC. The increase in ghrelin levels in patients with a positive CT response to pentagastrin, together with the immunopositivity for ghrelin in some MTC cells, suggests C cells as minor source of ghrelin production.