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PubMed1997

[Somatic ret proto-oncogene mutations in sporadic C-cell carcinoma of the thyroid gland].

Germline mutations of the RET proto-oncogene localized on chromosome 10q11.2 are the underlying cause of hereditary medullary thyroid carcinoma. In MEN 2A and FMTC, mutations can be found in exons 10, 11, 13 or 14. MEN 2B is characterized by a specific mutation in exon 16. In a significant number of sporadic MTC somatic mutations in codon 918 (exon 16) are detectable. Some rare sporadic MTC present somatic mutations in codons 611, 634, 768 and 883. Recently, deletion-insertion of the RET proto-oncogene in exon 11 and a deletion in exon 10 has been found. RET proto-oncogene mutations are not only responsible for the development of the familial MTC, but may also play an important role in the pathogenesis of sporadic MTC. However, the prognostic relevance of these somatic events is still unclear.

Carcinoma, Medullary↗

PubMed2003

The newly detected mutations in the RET proto-oncogene in exon 16 as a cause of sporadic medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) occurs as a sporadic form or, less frequently, as an autosomal dominant inherited familial disorder. Germline mutations in the RET proto-oncogene in exons 10, 11, 13, 14, 15, and 16 are found in most of the familial cases (nearly 95%). Somatic mutations in sporadic MTC are detected in 23-69% of patients. The most frequent somatic mutation is located in exon 16 at codon 918, and only a small percentage of mutations are found in exons 10, 11, 13, and 15. We have searched for somatic mutations in Czech MTC patients using direct sequencing. We report here two new somatic missense mutations in exon 16 of the RET proto-oncogene associated with the sporadic MTC detected in two Czech men. A homozygous mutation at codon 922 TCC(Ser)-->CCC(Pro) as a result of loss of heterozygosity was revealed in the first patient. In the second one a heterozygous mutation at codon 930 ACG(Thr)-->ATG(Met) was found.

Carcinoma, Medullary↗

PubMed1998

27-bp deletion in the ret proto-oncogene as a somatic mutation associated with medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) occurs as a sporadic tumor or in connection with the inherited cancer syndromes of multiple endocrine neoplasia (MEN) types 2A and 2B and familial MTC. Missense RET proto-oncogene mutations of one of cysteine codons in exons 10 and 11 are found in the majority of families with MEN 2A and or familial MTC. In MEN 2B, mutations at codon 918, exon 16, have been identified in most of the affected individuals. In a significant amount of sporadic MTC somatic codon 918 mutations appear. In addition to these, a 6-bp deletion including codon 630 and a 24-bp deletion including codon 634 combined with a 6-bp insertion have been observed. We report on a 27-bp deletion in exon 10 as a somatic mutation associated with a sporadic medullary thyroid carcinoma.

Amino Acid Sequence↗

PubMed2001

Three novel mutations in the RET proto-oncogene.

Medullary thyroid carcinoma (MTC) occurs as a sporadic tumor or in connection with inherited cancer syndromes of multiple endocrine neoplasia type 2 and familial MTC. Missense RET proto-oncogene mutations and small in-frame deletions are found in most of the cases. In a significant amount of sporadic MTC cases somatic mutation at codon 918 (exon 16), or at codons 609, 611, 618, 620 (exon 10), or codons 630, 634 (exon 11) appear. We report here on three new somatic cell missense mutations of the RET proto-oncogene associated with sporadic MTC. In one tumor mutation at codon 922 TCC(Ser)-->TTC(Phe) in exon 16 was found. In another tumor two mutations at codons 639 GCA(Ala)-->GGA(Gly) and 641 GCT(Ala)-->CGT(Arg) in the exon 11 were observed. Allele-specific PCR followed by sequencing demonstrated the presence of both mutations at the same allele.

Base Sequence↗

PubMed2000

Cholecystokinin receptor imaging using an octapeptide DTPA-CCK analogue in patients with medullary thyroid carcinoma.

UNLABELLED: Cholecystokinin (CCK)-B receptors have been demonstrated on a high percentage of medullary thyroid carcinomas (MTC) in vitro. After encouraging results both in vitro and in animal studies, we studied the efficacy of an octapeptide [111In-DTPA]-CCK analogue in seven patients with MTC. In four of five patients in whom serum calcitonin levels were monitored, a significant rise was found following the injection, indicating retained biological activity of the radiopeptide. In all patients there was visualization of the CCK-B receptor-positive stomach. In one of two patients with known MTC lesions, some of the lesions were visualized; in addition some lesions were visualized in one of the five other patients who had elevated serum tumour markers but negative localizing studies. Radioactivity in the presumed tumour sites was still present at 48 h p.i. The uptake in the presumed tumour sites and stomach was low. Background radioactivity dropped rapidly owing to urinary excretion. After 1 h, breakdown products of the labelled analogue predominated both in urine and in serum, and virtually no intact peptide was present. IN CONCLUSION: (1) the CCK-B receptor-positive gastric mucosa and presumed MTC lesions could be visualized in patients using an octapeptide [111In-DTPA]-CCK analogue that is probably internalized, proving the feasibility of CCK-B receptor imaging in vivo; (2) there was a relatively low uptake of the CCK analogue in the strongly CCK receptor positive stomach, and rapid degradation of the peptide in serum.

Carcinoma, Medullary↗

PubMed1998

Use of somatostatin analogue scintigraphy in the localization of recurrent medullary thyroid carcinoma.

Detection of recurrence of medullary thyroid carcinoma (MTC) remains a diagnostic problem. Increased serum tumour marker levels frequently indicate recurrence while conventional imaging techniques (CIT) are non-diagnostic. In this study, we performed indium-111 octreotide scintigraphy and CIT in a series of 20 patients with MTC presenting with elevated serum tumour markers after surgery. 111In-octreotide whole-body studies detected 15 pathological uptake foci in 11 of the 20 patients studied and CIT detected 17 lesions in 11 of the 20 patients. Ten patients underwent reoperation, five of them with positive 111In-octreotide scintigraphy and CIT and two with positive isotopic exploration and negative CIT. Surgical findings demonstrated that the results of isotopic study and CIT had been false-positive for MTC in one case (sarcoidosis). The six patients with true-positive 111In-octreotide studies had significantly higher basal calcitonin (CT) and carcinoembryonic antigen (CEA) levels than the patients with negative isotopic studies. The expression of somatostatin receptor (SSTR) subtypes by PC-PCR could be investigated in four cases with a positive isotopic study. Among the three cases with a true-positive study, SSTR2, the SSTR subtype that preferentially binds to the somatostatin analogue octreotide, was detected in two, SSTR5 was demonstrated in the three, and SSTR3 was detected in one. No subtype of SSTR was detected in the case with a final diagnosis of sarcoidosis. We conclude that 111In-octreotide has limited sensitivity in detecting recurrence in patients with MTC, although its sensitivity may improve with high serum CT levels. This radionuclide imaging technique should be employed when conventional imaging techniques are negative or inconclusive or when the presence of somatostatin receptors may provide the basis for treatment with somatostatin analogues.

Adult↗

PubMed2000

The value of fluorine-18 fluorodeoxyglucose PET in patients with medullary thyroid cancer.

The early detection of metastases from medullary thyroid cancer (MTC) is important because the only curative therapy consists in surgical removal of all tumour tissue. There is no single sensitive diagnostic imaging modality for the localization of all metastases in patients with MTC. Therefore, in many cases several imaging modalities (e.g. ultrasonography, magnetic resonance imaging, computerized tomography and scintigraphy using pentavalent technetium-99m dimercaptosuccinic acid, thallium-201 chloride, indium-111 pentetreotide, anti-CEA antibodies or metaiodobenzylguanidine) must be performed consecutively in patients with elevated calcitonin levels until the tumour is localized. In this prospective study, we investigated the value of fluorine-18 fluorodeoxyglucose positron emission tomography ([18F]FDG PET) in the follow-up of patients with MTC. [18F]FDG PET examinations of the neck and the chest were performed in 20 patients with elevated calcitonin levels or sonographic abnormalities in the neck. Positive [18F]FDG findings were validated by histology, computerized tomography or selective venous catheterization. [18F]FDG PET detected tumour in 13/17 patients (nine cases were validated by histology, four by computerized tomography). Five patients showed completely negative PET scans (of these cases, one was true-negative and four false-negative). One patient with [18F]FDG accumulation in pulmonary lesions from silicosis and one patient with a neck lesion that was not subjected to histological validation had to be excluded. Considering all validated localizations, [18F]FDG PET detected 12/14 tumour manifestations in the neck, 6/7 mediastinal metastases, 2/2 pulmonary metastases and 2/2 bone metastases. In two patients with elevated calcitonin levels, no diagnostic modality was able to localize a tumour. The sensitivity of [18F]FDG PET in the follow-up of MTC was 76% (95% confidence interval 53%-94%); this is encouraging. [18F]FDG PET promises to be a valuable diagnostic method, especially for the detection of lymph node metastases, surgical resection of which can result in complete remission.

Adult↗

PubMed2001

Pattern of nodal metastasis for primary and reoperative thyroid cancer.

This retrospective investigation was undertaken to clarify the pattern of nodal metastasis in papillary (PTC) and medullary (MTC) thyroid carcinoma. Nodal metastases are associated with recurrence of both PTCs and MTCs. The extent of lymph node dissection is controversial owing to the lack of reliable diagnostic criteria for nodal metastases other than histopathology. Between November 1994 and October 1999 a total of 296 patients (134 PTCs, 162 MTCs) underwent total thyroidectomy in conjunction with a standard resection of at least the cervicocentral lymph node compartment. Of 10,446 sampled lymph nodes, 1641 were positive. All nodes were related to their respective cervicomediastinal compartments. The ipsilateral cervicolateral compartment was involved almost as often as the cervicocentral compartment in primary PTC (29% vs. 32%), reoperative PTC (21% vs. 37%), primary MTC (34% vs. 34%), and reoperative MTC (49% vs. 65%). The contralateral cervicolateral and mediastinal compartments were more rarely affected, and were least affected in the primary setting. From these data was derived an individualized surgical strategy for PTC and MTC. This concept rests on the joint resection of cervicocentral and ipsilateral cervicolateral compartments. Depending on tumor entity, surgical status, and primary tumor diameter, additional compartments may have to be cleared.

Carcinoma, Medullary↗

PubMed2004

Timing and extent of surgery in patients with familial medullary thyroid carcinoma/multiple endocrine neoplasia 2A-related RET mutations not affecting codon 634.

In hereditary medullary thyroid carcinoma (MTC), recommendations regarding timing and extent of surgery are mainly based on the data of patients with the codon 634 RET mutation, which is the most often affected codon. Little is known about whether these recommendations may also be applied to patients with less common RET mutations. We ascertained the data from 140 patients with FMTC/MEN2A-related RET mutation not affecting codon 634 who have been treated at three specialized centers. The several RET mutations found affected codons 611 (n = 17), 618 (n = 22), 620 (n = 17), 768 (n = 9), 790 (n = 24), 791 (n = 21), 804 (n = 23), and 891 (n = 7). For each codon, the age of the youngest patient with MTC only (41, 7, 18, 29, 13, 47, 20, and 15 years, respectively), MTC with lymph node metastases (46, 24, 21, 34, 46, 47, 50, and 76 years, respectively), and MTC with distant metastases (52, 69, 43, 68, 57, - , - , and 75 years, respectively) was determined. All patients with lymph node metastases had elevated basal calcitonin levels. Based on these data, a more individual recommendation regarding timing and extent of surgery can be given. Because neither gender nor the type of nucleotide substitution for a specific codon appeared to have a significant influence on the age of onset, this recommendation should be based on the affected codon, the age of the patient, and the calcitonin level. Recurrent laryngeal nerve palsy (n = 6) and hypoparathyroidism (n = 3) were rather rare and were found only in patients older than 30 and 43 years, respectively, giving evidence that surgery in young patients can be performed safely.

Adolescent↗

PubMed2006

Desmoplastic stromal reaction in medullary thyroid cancer-an intraoperative "marker" for lymph node metastases.

BACKGROUND: Medullary thyroid cancer (MTC) disseminates early to lymph nodes (LN). There is no pre- or intraoperative marker to exclude LN involvement and thereby avoid lateral neck dissection in LN-negative patients. MATERIALS AND METHODS: This study was intended to verify the observation that patients with MTC lacking desmoplastic stromal reaction (DSR) never have LN metastases. In 120 patients undergoing primary operation for sporadic MTC the prognostic value of DSR with respect to LN involvement was evaluated. RESULTS: Thirty-two (27%) of 120 tumors were DSR negative, and 88 (73%) were DSR positive. All 32 (100%) DSR-negative tumors were LN negative (N0), and all patients were biochemically cured. Of 88 DSR-positive tumors, 57 (65%) were staged N0, and 31 (36%) were staged N1(LN positive; Fisher's exact test: P = 0.0001). In a comparison of the LN involvement to the DSR characteristics, 32 (36%) of the 89 N0 patients and none of the 31 N1 patients were DSR negative. The sensitivity of DSR in predicting N0 is 38% (95% confidence interval: CI 95% = 27 %-55%), the specificity is 100% (CI 95% = 88%-100%). The sensitivity and specificity for the parameter DSR to differentiate between N0 or N1 were 100% and 36%, respectively. CONCLUSIONS: The desmoplastic stromal reaction appears to be an excellent intraoperative marker to predict LN involvement with a high specificity but low sensitivity. We therefore propose to avoid initial lateral neck dissection in MTC patients without DSR.

Adult↗

PubMed2003

Intravesical administration of doxorubicin to swine bladder using magnetically targeted carriers.

PURPOSE: The feasibility of using magnetic targeted carriers (MTC) to deliver doxorubicin intravesically was studied in normal swine bladder. MTCs are microparticles consisting of metallic iron and activated carbon. Doxorubicin is adsorbed to the activated carbon component of the MTCs (MTC-DOX) while the iron component provides magnetic susceptibility. This technology is designed for site-specific delivery of a drug to a tumor in the presence of an externally applied magnetic field in order to achieve prolonged release of high localized drug concentrations by retention of MTCs in the region of interest. An intravesical route of administration was evaluated as intravesical chemotherapy is used in the treatment of bladder cancer. METHODS: The urethras of six swine were catheterized and Foley catheters were placed in their bladders. The effects of doses ranging from 10 to 80 mg doxorubicin adsorbed onto 300 to 800 mg MTCs were studied. A 30-min period of magnetic targeting immediately followed dosing, in which an external magnet was placed on the skin surface over a predetermined site on the bladder. The subsequent retention and distribution of test material was evaluated by measurement of doxorubicin levels in plasma and histopathological examination of the bladder following treatment. Blood samples were taken prior to treatment and at 15 and 30 min after infusion for measurement of doxorubicin. The bladder was drained and rinsed thoroughly following the procedure. RESULTS: Plasma doxorubicin concentrations were less than the assay limit of detection (10 ng/ml) during the 30 min following dosing. MTCs were found within the bladder walls, predominantly at the targeted site where they were present at greater depths within the layers of the epithelium. The study results show that MTC-DOX can be targeted and retained within specific locations in the bladder using magnetic targeting. CONCLUSIONS: MTC delivery may allow greater exposure and specific deposition of drug at a defined site over intravesical administration of doxorubicin alone. The feasibility of this novel method of drug delivery was demonstrated and the results support further study for its potential use in treating bladder cancer.

Animals↗

PubMed2001

Is there any consensus in diagnostic and operative strategy with respect to medullary thyroid cancer? A questionnaire answered by 73 endocrine surgical units.

BACKGROUND: The purpose of this investigation was to analyze the individual diagnostic and operative strategy in the treatment of medullary thyroid carcinoma (MTC) in international specialized centers and to assess whether standard procedures are carried out in practice everywhere. METHODS: A questionnaire concerning diagnosis and treatment of patients with primary, persistent, or recurrent sporadic or familial MTC was sent to 263 members of the International Association of Endocrine Surgeons. RESULTS: Primary treatment of MTC does not show significant differences for patients with sporadic or familial disease (Chi-square, n.s.), and standard procedures are performed in only 25-40% of patients. Computed tomography scan is the most common localization procedure in persistent or recurrent disease (52-72%), followed by scintigraphy (43-71%), ultrasonography (41-56%), and magnetic resonance imaging (31-49%). In case of negative localization studies, 68-86% of colleagues do not recommend reoperation. In symptomatic patients with stage-IV tumors, however, 84% of colleagues advocate reoperation to provide relief from the tumor burden. CONCLUSIONS: Even with experienced endocrine surgeons, a consensus to uni- and/or bilateral neck dissection in primary MTC is lacking. The majority of authors supports at least total thyroidectomy with central lymph-node dissection. In recurrent disease, there is a general tendency to reoperate in case of positive localization studies and in case of symptomatic disease.

Carcinoma, Medullary↗

PubMed2001

Surgery on the cervicovisceral axis for invasive thyroid cancer.

BACKGROUND AND AIMS: Invasion of the cervicovisceral axis (i.e., larynx trachea esophagus) by thyroid cancers still poses a surgical challenge. PATIENTS AND METHODS: Between November 1994 and October 1999, all patients who underwent surgery at this institution for differentiated (DTC) or medullary (MTC) thyroid carcinoma invading the cervicovisceral axis were recruited into this study. RESULTS: The cervicovisceral axis was invaded in 34 consecutive patients (19 DTC, 15 MTC). Of these, 20 patients underwent cervicovisceral resections. These resections were performed less often in MTC than in DTC patients (20% versus 89%; P<0.0001). Full-thickness invasion was present in 3 patients (2 DTC, 1 MTC). In the 20 resectional patients, tracheal wedge resection was the most common procedure followed by extramucosal esophageal resection. Surgical mortality was nil. There were five major complications, most of which occurred in either lateral tracheal or high-risk combined laryngo-tracheo-esophageal resections. CONCLUSION: The surgical approach to invasive thyroid carcinoma must balance surgical morbidity against the potential benefits of cervicovisceral resection. Individual factors must be considered, such as patient age and co-morbidity, the extent and nature of the tumor, and quality-of-life issues. Lateral resection of the trachea may cause significant tracheal instability and morbidity and, thus, be inferior to segmental tracheal resection.

Carcinoma, Medullary↗

PubMed1999

Expression of laminin-2 by normal and neoplastic rat C cells during the development of medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) originates from C cells, which secrete calcitonin (CT), their specific marker. C cells are located in contact with the basement membrane (BM) of the thyroid follicles, which is partly made up of the laminin-2 isoform synthesized by thyrocytes. During oncogenesis, proliferation of the C cells, invading the centre of the follicles, leads to a break in their normal contact with the BM. As specific interactions of cells with BM components, especially laminins, are important for proliferation and differentiation, we investigated the relationships of normal and neoplastic C cells with laminin in the Wag/Rij rat model of human MTC. Immunocytochemical studies showed a progressive loss of the laminin layer underlying the hyperplastic C cell nodules around the large dedifferentiated tumours. The alpha2, beta1 and gamma1 chains of the laminin-2 isoform were synthesized and secreted by rat MTC 6-23 cell cultures and the tumours induced by subcutaneous injection of these cells. In situ hybridization combined with anti-CT immunocytochemistry showed a low expression of alpha2 mRNA on differentiated C cells and thyrocytes, but an overexpression on immunonegative spontaneous MTC and induced intrathyroid tumours. The high level of alpha2 gene expression, together with tumour dedifferentiation, suggests a relationship with malignancy.

Animals↗

PubMed2004

The role of combined imaging in metastatic medullary thyroid carcinoma: 111In-DTPA-octreotide and 131I/123I-MIBG as predictors for radionuclide therapy.

PURPOSE: The medical treatment of metastatic medullary thyroid carcinoma (MTC) is still questionable. The aim of this study was to evaluate a combined imaging protocol using 111In-DTPA-octreotide and 131I/123I-MIBG to decide whether targeted radiotherapy would be useful, and which radiopharmaceutical (90Y-DOTATOC or 131I-MIBG) would be more effective. METHODS: Eight patients (four men, four women; mean age 61 years) with metastatic MTC were included. Treatments were performed with 3,330 MBq 90Y-DOTATOC at 6-week intervals, or 11.1 GBq 131I-MIBG with a minimum interval of 3 months. RESULTS: The imaging procedure was positive in all eight patients: 111In-DTPA-octreotide imaging in five patients, 131I/123I-MIBG imaging in four patients. With respect to the number of metastatic lesions, MIBG imaging was less effective than octreotide. According to the results of combined imaging, we identified one patient to be treated with 90Y-DOTATOC, and three patients with 131I-MIBG. An overall antitumor effect was observed in all four patients, one with partial remission and three with stable disease. No relevant toxicity was observed. CONCLUSIONS: The combined imaging can increase the detection rate of metastatic foci in patients with MTC and identify more patients for effective radionuclide treatment. The treatment with 90Y-DOTATOC or 131I-MIBG is well tolerated and may improve the fate of patients with metastatic MTC.

3-Iodobenzylguanidine↗

PubMed1998

Hepatectomy with microwave tissue coagulation for hepatocellular carcinoma.

From 1984 through 1994, 99 consecutive patients with hepatocellular carcinoma (HCC) underwent hepa-tectomy with microwave tissue coagulation (MTC). We performed limited resection (Hr0) in 28 patients, subsegmentectomy (HrS) in 25 patients, segmentectomy (Hr1) in 21 patients, and lobectomy or extended lobectomy (Hr2) in 25 patients. The patients were divided into two groups: group A, 86 patients with tumors smaller than 1 kg and no tumor thrombi in the main portal trunk; and group B, 13 patients with a tumor 1 kg or larger, or with macroscopic tumor thrombi in the main portal trunk. In group A, mean blood loss was 838 ml for Hr0, 1948 ml for HrS, 1765 ml for Hr1, and 1325 ml for Hr2. The mean operative time in group A ranged from 3 h 43 min for Hr0 to 4 h 57 min for Hr2. In group B, the mean operative time was 6 h 3 min and mean blood loss was 6053 ml. Our MTC method was associated with an in-hospital mortality rate of 3% and a major complication rate of 13.1%. The 5-year survival and disease-free survival rates were 43.4% and 25.4%, respectively. The 5-year survival rate of patients without portal tumor thrombi (50.9%) was significantly better than that of patients with portal tumor thrombi (11.9%) (P < 0.001). The 5-year survival rate of patients who underwent curative resection (58.1%) was significantly better than that of patients who underwent noncurative resection (22.9%) (P < 0.001). The 5-year survival rates of patients in group A without portal tumor thrombi did not differ between those who had cancer-negative margins (54.0%) and those with cancerpositive margins (49.6%) at resection. Recurrence and local recurrence rates did not differ in patients with cancer-positive margins (63.6% and 7.3%, respectively) and patients with cancer-negative margins (56.5% and 8.7%, respectively). These results suggested that microscopic residual cancer in the resected margin was coagulated by MTC. Blood loss, operative time, and clinical outcome in this series of 99 consecutive hepatectomies were comparable with values in earlier reports in which such hemostatic methods as the Pringle maneuver were used. We conclude that hepatectomy with MTC is useful and safe and produces consistent results.

Adult↗

PubMed2000

Evaluation of a fluorescence hybridisation assay using peptide nucleic acid probes for identification and differentiation of tuberculous and non-tuberculous mycobacteria in liquid cultures.

The performance was evaluated of a fluorescence in situ hybridisation assay using peptide nucleic acid probes (Dako Probe MTB Culture Confirmation Test; Dako, Denmark) for identification of Mycobacterium tuberculosis complex (MTC) organisms and differentiation between tuberculous and non-tuberculous mycobacteria (NTM) in material taken directly from Bactec 12B (Becton Dickinson, USA) and MB/BacT (Organon Teknika, USA) bottles. The test was applied to 129 smear-positive (Ziehl-Neelsen stain) clinical specimens, 48 previously identified clinical strains of mycobacteria (12 MTC and 36 NTM), and 51 reference strains (7 MTC and 44 NTM) which were all previously inoculated into Bactec 12B and MB/BacT bottles. The sensitivity and specificity of the assay for MTC-positive cultures was 87.6% and 100%, respectively, for Bactec 12B, and 100%, respectively, for MB/BacT. The sensitivity and specificity of the assay for NTM-positive cultures was 100% for both media.

Culture Media↗

PubMed2003

Medullary thyroid carcinoma.

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy that occurs in hereditary (25%) and sporadic (75%) clinical settings. MTC is present in all patients with the multiple endocrine neoplasia type 2 syndromes. MTCs produce calcitonin, the measurement of which can indicate the presence of tumors in people who are at risk and the effectiveness of therapy in treated patients. Surgical cure is possible in young patients with multiple endocrine neoplasia type 2 who undergo preventative thyroidectomy (approximately 50% of patients who are diagnosed with a palpable thyroid mass) and in some patients with recurrent nodal metastatic disease in the neck. Mortality from MTC is caused by tumor invasion of the trachea, great vessels in the neck, or mediastinum or by the effects of distant metastatic disease. Surgery for cervical recurrence can prevent death from tracheal invasion. The role of radiation therapy is not well defined. There is no effective systemic therapy for MTC. Activating mutations in a tyrosine kinase receptor gene (RET) are present in most MTCs, and experience with tyrosine kinase inhibitors and other agents in clinical trials is critical for the identification of effective systemic treatment.

Carcinoma, Medullary↗