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Selpercatinib, a selective RET kinase inhibitor, has demonstrated remarkable efficacy in treating patients with advanced medullary (MTC) and differentiated thyroid cancer with RET alterations. Primary resistance to selpercatinib is a very uncommon situation, and its underlying mechanisms are poorly understood. We report the case of a 42-year-old female with advanced MTC harboring a somatic M918T RET mutation who exhibited a primary resistance to selpercatinib. Despite prompt treatment initiation after the diagnosis of progressive disease, the patient continued experiencing rapid spread of disease, characterized by the appearance of new metastatic lesions and increased tumor burden. Genomic analysis revealed no additional mutations associated with on-target or off-target resistance. This case highlights a rare clinical scenario of primary resistance to selpercatinib in advanced MTC. While secondary resistance mechanisms have been well-documented, primary resistance remains poorly understood. Possible explanations include tumor heterogeneity and activation of alternative signaling pathways that stills need to be elucidated. Emerging therapies targeting resistance mechanisms and next-generation RET inhibitors offer promising avenues for further investigation.

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Genetic testing for germline RET pathogenic variants, which cause the Multiple Endocrine Neoplasia Type 2 (MEN2) syndrome, has become crucial in managing patients with medullary thyroid carcinoma (MTC). Classically, RET heterozygous missense pathogenic variants are transmitted in a Mendelian autosomal dominant pattern, of which germline/gonadal mosaicism has never been reported. We report the novel occurrence of a MEN2A patient's family in which the siblings inherited three different RET 634 genotypes: wild type (p.Cys634), p.Cys634Gly or p.Cys634Arg heterozygous pathogenic variants. We hypothesized that germline/gonadal mosaicism, derived from an inherited + early somatic mutation in the mother or a double de novo mutation during maternal embryogenesis, led to this rare event in the RET gene. Exome analysis of the proband's deceased mother's paraffin-embedded thyroid tissue confirmed the three nucleotides in the same 634 codon position. For the first time, we describe germline/gonadal mosaicism in RET, generating a second pathogenic amino acid change in the same codon causing MEN2A. Our finding shows that RET parental mosaicism, confirmed by somatic exome sequencing, might explain discrepant genotype cases in siblings with inherited cancers.

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Objective: The purpose of these guidelines is to provide specific recommendations for the surgical treatment of neck metastases in patients with papillary, follicular, and medullary thyroid carcinomas. Materials and methods: Recommendations were developed based on research of scientific articles (preferentially meta-analyses) and guidelines issued by international medical specialty societies. The American College of Physicians' Guideline Grading System was used to determine the levels of evidence and grades of recommendations. The following questions were answered: A) Is elective neck dissection indicated in the treatment of papillary, follicular, and medullary thyroid carcinoma? B) When should central, lateral, and modified radical neck dissection be performed? C) Could molecular tests guide the extent of the neck dissection? Results and conclusion: Recommendation 1: Elective central neck dissection is not indicated in patients with cN0 well-differentiated thyroid carcinoma or in those with noninvasive T1 and T2 tumors but may be considered in T3-T4 tumors or in the presence of metastases in the lateral neck compartments. Recommendation 2: Elective central neck dissection is recommended in medullary thyroid carcinoma. Recommendation 3: Selective neck dissection of levels II-V should be indicated to treat neck metastases in papillary thyroid cancer, an approach that decreases the risk of recurrence and mortality. Recommendation 4: Compartmental neck dissection is indicated in the treatment of lymph node recurrence after elective or therapeutic neck dissection; "berry node picking" is not recommended. Recommendation 5: There are currently no recommendations regarding the use of molecular tests in guiding the extent of neck dissection in thyroid cancer.

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Background: Calcitonin measurement is widely used in the diagnosis, prognosis, and follow-up of patients with medullary thyroid carcinoma (MTC). The prognostic value of undetectable postoperative calcitonin (POCal) in long-term disease outcomes remains uncertain. Objective: The aim of this study is to evaluate POCal as a prognostic marker for long-term MTC disease status. Methods: A retrospective cohort study was carried out. We collected data from the medical records of patients with MTC attending two tertiary teaching hospitals. Patients were divided according to POCal into two groups: undetectable (below the detection limit) or detectable. The outcome was determined at the last medical visit and defined as disease free (undetectable calcitonin and no evidence of disease on imaging), persistent disease (detectable calcitonin with or without structural disease), or disease-related death. Results: Three hundred thirty-four MTC patients were included in the study. The mean age at diagnosis was 41.1 ± 18.6 years; 202 patients (60.5%) were women; and 167 patients (50.0%) had sporadic MTC. The median tumor size was 2.0 cm (1.1-3.5 cm); 164 patients (49.1%) had lymph node metastasis and 63 patients (18.9%) had distant metastasis. At the first postoperative evaluation (3-6 months after surgery), 141 patients had undetectable POCal (mean age = 37.9 years, 70.9% women, median tumor size 1.5 cm [0.7-2.5 cm]; 28 [19.9%] had lymph node metastasis and none had distant metastasis). After a median follow-up of 7.7 years (2.1-13.2 years), 127 (90.1%) of these patients were free of disease, whereas 14 (9.9%) had persistent biochemical disease with stable calcitonin levels. No patient with undetectable POCal died of the disease. In the detectable POCal group (mean age = 42.9 years, 52.8% women, median tumor size 3.0 cm [1.8-4.2 cm]; 136 [70.5%] had lymph node metastasis and 63 [32.6%] had distant metastasis), 18 (9.2%) patients achieved disease-free status, 51 (26.6%) had biochemical disease, and 61 (31.6%) had persistent structural disease. Sixty-three (32.6%) patients died of disease-related events. Further analysis using a multivariate model identified undetectable POCal as an independent prognostic variable for disease-free status (HR = 5.33, CI = 2.86-9.94; p < 0.001). Conclusions: POCal is a strong prognostic marker for long-term disease-free survival and might help define follow-up strategies for MTC patients.

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ABSTRACT Objective: The purpose of these guidelines is to provide specific recommendations for the surgical treatment of neck metastases in patients with papillary, follicular, and medullary thyroid carcinomas. Materials and methods: Recommendations were developed based on research of scientific articles (preferentially meta-analyses) and guidelines issued by international medical specialty societies. The American College of Physicians' Guideline Grading System was used to determine the levels of evidence and grades of recommendations. The following questions were answered: A) Is elective neck dissection indicated in the treatment of papillary, follicular, and medullary thyroid carcinoma? B) When should central, lateral, and modified radical neck dissection be performed? C) Could molecular tests guide the extent of the neck dissection? Results/conclusion: Recommendation 1: Elective central neck dissection is not indicated in patients with cN0 well-differentiated thyroid carcinoma or in those with noninvasive T1 and T2 tumors but may be considered in T3-T4 tumors or in the presence of metastases in the lateral neck compartments. Recommendation 2: Elective central neck dissection is recommended in medullary thyroid carcinoma. Recommendation 3: Selective neck dissection of levels II-V should be indicated to treat neck metastases in papillary thyroid cancer, an approach that decreases the risk of recurrence and mortality. Recommendation 4: Compartmental neck dissection is indicated in the treatment of lymph node recurrence after elective or therapeutic neck dissection; "berry node picking" is not recommended. Recommendation 5: There are currently no recommendations regarding the use of molecular tests in guiding the extent of neck dissection in thyroid cancer.

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PURPOSE: 18F-DOPA Positron Emission Tomography/Computed Tomography (18F-DOPA PET/CT) is a sensitive functional imaging method (65-75%) for detecting disease localization in medullary thyroid cancer (MTC). We aimed: (i) to assess the clinical usefulness of 18F-DOPA PET/CT in patients with MTC and elevated calcitonin (Ctn) and CEA levels and, (ii) to evaluate changes in disease management secondary to the findings encountered with this methodology. METHODS: Thirty-six patients with MTC and Ctn levels ≥150 pg/ml were prospectively included. Neck ultrasound, chest contrast-enhanced CT, liver magnetic resonance imaging/abdominal three-phase contrast-enhanced CT and bone scintigraphy were carried out up to 6 months before the 18F DOPA PET/CT. RESULTS: Seventy eight percent of patients were female and 27% had hereditary MTC. Median Ctn level was 1450 pg/ml [150-56620], median CEA level 413 ng/ml [2.9-7436]. Median Ctn DT was 37.5 months [5.7-240]; median CEA DT was 31.8 [4.9-180]. 18F-DOPA PET/CT was positive in 33 patients (91.6%); in 18 (56%) uptake was observed in lymph nodes in the neck or mediastinum, in seven cases (22%) distant metastases were diagnosed, and in eight additional patients (24%) both locoregional and distant sites of disease were found. Ctn and CEA levels were higher in patients with ≥3 foci of distant metastases. In 14 patients (38.8%), findings on 18F-DOPA PET/CT led to changes in management; surgery for locoregional lymph nodes was the most frequent procedure in 8 patients (22%). CONCLUSION: 18F-DOPA PET/CT was useful for the detection of recurrent disease in MTC, providing incremental value over conventional imaging procedures that led to modification in treatment strategies in nearly 40% of patients.

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ABSTRACT Objective: To verify the cytopathological Bethesda System classification of thyroid nodule fine-needle aspiration biopsy (FNAB) in MTC patients and to assess the role of preoperative serum calcitonin (CT) levels in the investigation of this neoplasm in medullary thyroid cancer (MTC) patients under observation at the Uopeccan (União Oeste Paranaense de Estudos e Combate ao Câncer). Materials and methods: This is a cross-sectional review of medical records of patients monitored at the thyroid cancer outpatient clinic of Uopeccan. Clinical and demographic data, laboratory tests, ultrasound images, and cytopathological findings of MTC patients were evaluated. Results and discussion: Among the 360 patients with thyroid cancer monitored in the outpatient clinic, 5.2% (n: 19/360) had MTC. The hereditary form was more prevalent (63.2%), and there was no sex preference. The most common ultrasound findings were hypoechogenicity, solid appearance and microcalcifications. The FNAB diagnoses showed a sensitivity of 47.1%, and the most common cytopathological report was Bethesda category III. Serum CT levels showed good sensitivity (84.6%) for the diagnosis of MTC, and sensitivity levels were directly associated with the size of the nodule and distant metastases. Conclusion: Bethesda category III was more prevalent in this group of MTC patients. Serum CT levels were more sensitive than cytopathology for diagnosis of this neoplasm and were able to identify all patients who could not be diagnosed by FNAB.

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OBJECTIVE: To verify the cytopathological Bethesda System classification of thyroid nodule fine-needle aspiration biopsy (FNAB) in MTC patients and to assess the role of preoperative serum calcitonin (CT) levels in the investigation of this neoplasm in medullary thyroid cancer (MTC) patients under observation at the Uopeccan (União Oeste Paranaense de Estudos e Combate ao Câncer). METHODS: This is a cross-sectional review of medical records of patients monitored at the thyroid cancer outpatient clinic of Uopeccan. Clinical and demographic data, laboratory tests, ultrasound images, and cytopathological findings of MTC patients were evaluated. RESULTS: Among the 360 patients with thyroid cancer monitored in the outpatient clinic, 5.2% (n: 19/360) had MTC. The hereditary form was more prevalent (63.2%), and there was no sex preference. The most common ultrasound findings were hypoechogenicity, solid appearance and microcalcifications. The FNAB diagnoses showed a sensitivity of 47.1%, and the most common cytopathological report was Bethesda category III. Serum CT levels showed good sensitivity (84.6%) for the diagnosis of MTC, and sensitivity levels were directly associated with the size of the nodule and distant metastases. CONCLUSION: Bethesda category III was more prevalent in this group of MTC patients. Serum CT levels were more sensitive than cytopathology for diagnosis of this neoplasm and were able to identify all patients who could not be diagnosed by FNAB.

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Medullary thyroid carcinoma (MTC) is a rare type of tumor that originates from thyroid C cells and accounts for 2-4% of all malignant thyroid neoplasms. MTC may occur sporadically or be inherited, as part of the MEN 2 syndrome. Germline mutations of the RET (REarranged during Transfection) proto-oncogene cause hereditary cancer, whereas somatic RET mutations and, less frequently, RAS mutations have been described in sporadic MTC samples. Since early surgery with complete resection of tumor mostly determines the likelihood of attaining cure for MTC, the broader use of RET genetic screening has dramatically changed the prognostic of gene carriers in hereditary MTC. Nevertheless, despite recent advances, the management of advanced, progressive MTC remains challenging. The multikinase inhibitors (MKI), vandetanib and cabozantinib, were approved for the treatment of progressive or symptomatic MTC, and several other compounds have exhibited variable efficacy. Although these drugs have been shown to improve progression-free survival, no MKI has been shown to increase the overall survival. As these drugs are nonselective, significant off-target toxicities may occur, limiting achievement of the required TK-specific inhibition. Recently, next-generation small-molecule TKI has been developed. These TKI are specifically designed for highly potent and selective targeting of oncogenic RET alterations, making them promising drugs for the treatment of advanced MTC. Here, we summarize the current understanding of the intracellular signaling pathways involved in MTC pathogenesis as well as the therapeutic approaches and challenges for the management of advanced MTC, focusing on targeted molecular therapies.

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ABSTRACT Objective: Because serum calcitonin (CT) is a reliable marker of the presence, volume, and extent of disease in medullary thyroid cancer (MTC), both the ATA and NCCN guidelines use the 2-3 month post-operative CT value as the primary response to therapy variable that determines the type and intensity of follow up evaluations. We hypothesized that the calcitonin would nadir to undetectable levels within 1 month of a curative surgical procedure. Subjects and methods: This retrospective review identified 105 patients with hereditary and sporadic MTC who had at least two serial basal CT measurements done in the first three months after primary surgery. Results: When evaluated one year after initial surgery, 42 patients (42/105, 40%) achieved an undetectable basal calcitonin level without additional therapies and 56 patients (56/84, 67%) demonstrated a CEA within the normal reference range. In patients destined to have an undetectable CT as the best response to initial therapy, the calcitonin was undetectable by 1 month after surgery in 97% (41/42 patients). Similarly, in patients destined to have a normalize their CEA, the CEA was within the reference range by 1 month post-operatively in 63% and by 6 months in 98%. By 6 months after curative initial surgery, 100% of patients had achieved a nadir undetectable calcitonin, 98% had reached the CEA nadir, and 97% had achieved normalization of both the calcitonin and CEA. Conclusion: The 1 month CT value is a reliable marker of response to therapy that allows earlier risk stratification than the currently recommended 2-3 month CT measurement.

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El cáncer medular de tiroides (CMT) correspondeal 5% de los tumores de la glándula tiroides. El único tratamiento curativo es la cirugía. En pacientes con compromiso locorregional o a distancia, la enfermedad puede evolucionar en forma indolente o bien con una rápida progresión de síntomas, requiriendo tratamiento sistémico. Si bien el CMT se caracteriza por tener escasa respuesta a la quimioterapia (QT), la evidencia actual en estudios aleatorizados demostró que los inhibidores de tirosina quinasa (ITQ) han demostrado beneficio en supervivencia libre de progresión (SLP). Se analizaron 6 pacientes con un seguimiento mediano de 29 meses. Todos presentaron más de dos sitios metastásicos. Dos requirieron tratamientos locorregionales (quimioembolización y RT). Los ITQ más utilizados fueron: vandetanib (3), sorafenib (2) y sunitinib (1). Un 50% inició tratamiento con dosis plenas y 3 requirieron reducción de dosis debido a toxicidad G3-G4. El intervalo libre de progresión (ILP) mediano, luego del inicio con ITQ, fue de 4.1 meses (AU)

Medullary thyroid cancer (CMT) accounts for 5% of thyroid tumors. The only curative treatment is surgery. In patients with locally or distal involvement, the disease may evolve indolently or with rapid progression of symptoms, requiring systemic treatment. Although CMT is characterized by a poor response to chemotherapy, current evidence in randomized trials has shown that tyrosine kinase inhibitors (ITKs) have demonstrated benefit in progressionfree survival. Six patients with a median follow-up of 29 months were analyzed. All had more than two metastatic sites. Two patients required locoregional treatments (chemoembolization and radio therapy). The most commonly used ITKs were: vandetanib (3), sorafenib (2) and sunitinib (1). The 50% initiated treatment with full dose and 3 required reduction of the dose due to G3- G4 toxicity. The median progression-free interval after initiation with ITK was 4.1 months (AU)

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El carcinoma de tiroides es un tumor infrecuente; constituye menos del 1% de las neoplasias malignas en la población general y el 0,5%-3% en la edad pediátrica. Existen cuatro tipos: papilar (80%-90% de los casos), folicular (5%-10%), medular (5%) y anaplásico (2%-3%). En el tipo medular, el 80% son esporádicos, y un 20% se asocia a un síndrome hereditario que se divide, fundamentalmente, en tres grupos: neoplasia endócrina múltiple 1, neoplasia endócrina múltiple 2 y carcinoma medular de tiroides familiar. Las formas hereditarias se producen por una mutación en el protooncogén RET, localizado en el brazo largo del cromosoma 10. Se presenta un caso de carcinoma medular de tiroides detectado a raíz de un estudio genético familiar con el propósito de resaltar la importancia del diagnóstico precoz y la intervención de equipos multidisciplinares expertos en esta patología para su manejo y seguimiento.

Thyroid cancer is an uncommon type of cancer, accounting less than 1% of all cancers in adults, and 0.5-3% of all cancers in children. There are four different types: papillary carcinoma (80-90% of cases), follicular (5-10%), medullary (5%) and anaplastic cell (2-3%). Eighty per cent of cases of medullary thyroid cancer are sporadic, but 20% are associated with an inherited syndrome that is divided into three groups: multiple endocrine neoplasia type 1, multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma. The inherited forms are caused by a disruption in the RET oncogene, which is located in the long arm of chromosome 10. A hereditary case of medullary thyroid carcinoma is presented. It was detected because of a familial genetic study. The purpose of the paper is emphasize the importance of the early diagnosis and the intervention of multidisciplinary teams of experts.

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Thyroid cancer is an uncommon type of cancer, accounting less than 1% of all cancers in adults, and 0.5-3% of all cancers in children. There are four different types: papillary carcinoma (80-90% of cases), follicular (5-10%), medullary (5%) and anaplastic cell (2-3%). Eighty per cent of cases of medullary thyroid cancer are sporadic, but 20% are associated with an inherited syndrome that is divided into three groups: multiple endocrine neoplasia type 1, multiple endocrine neoplasia type 2 and familial medullary thyroid carcinoma. The inherited forms are caused by a disruption in the RET oncogene, which is located in the long arm of chromosome 10. A hereditary case of medullary thyroid carcinoma is presented. It was detected because of a familial genetic study. The purpose of the paper is emphasize the importance of the early diagnosis and the intervention of multidisciplinary teams of experts.

El carcinoma de tiroides es un tumor infrecuente; constituye menos del 1% de las neoplasias malignas en la población general y el 0,5%-3% en la edad pediátrica. Existen cuatro tipos: papilar (80%-90% de los casos), folicular (5%-10%), medular (5%) y anaplásico (2%-3%). En el tipo medular, el 80% son esporádicos, y un 20% se asocia a un síndrome hereditario que se divide, fundamentalmente, en tres grupos: neoplasia endócrina múltiple 1, neoplasia endócrina múltiple 2 y carcinoma medular de tiroides familiar. Las formas hereditarias se producen por una mutación en el protooncogén RET, localizado en el brazo largo del cromosoma 10. Se presenta un caso de carcinoma medular de tiroides detectado a raíz de un estudio genético familiar con el propósito de resaltar la importancia del diagnóstico precoz y la intervención de equipos multidisciplinares expertos en esta patología para su manejo y seguimiento.

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Medullary thyroid carcinoma (MTC) may rarely present with paraneoplastic syndromes. Among the most frequent ones are the appearance of diarrhea and ectopic Cushing syndrome (ECS). The ECS in the context of MTC is usually present in patients with distant metastatic disease. The use of drugs such as ketoconazole, metyrapone, somatostatin analogs and etomidate have been ineffective alternatives to control hypercortisolism in these patients. Bilateral adrenalectomy is often required to manage this situation. Recently, the use of tyrosine kinase inhibitors has been shown to be a useful tool to achieve eucortisolism in patients with metastatic MTC and ECS. We present a patient with sporadic advanced persistent and progressive MTC with lymph node and liver metastases, which after 16 years of follow-up developed an ECS. After one month of 300 mg/day vandetanib treatment, a biochemical and clinical response of the ECS was achieved but it did not result in significant reduction of tumor burden. However the patient reached criteria for stable disease according to response evaluation criteria in solid tumors (RECIST 1.1) after 8 months of follow-up.

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Ante la baja frecuencia del carcinoma medular de tiroides (CMT), en el Departamento de Tiroides de SAEM nos propusimos realizar un estudio de cohorte, observacional, retrospectivo y multicéntrico. Se incluyeron 219 pacientes con diagnóstico histológico de CMT. El 65 % fueron mujeres, la edad promedio fue de 39 ± 20 años (1 a 84 años); 44-% de los casos fueron familiares. Las formas de presentación más frecuentes fueron nódulo tiroideo (58 %) y pesquisa genética por antecedente familiar (22 %). Si bien la citología tiroidea fue diagnóstica de CMT en el 39 % de los casos, fue determinante de indicación quirúrgica en el 79 %. En el 47 % de los pacientes el diagnóstico de CMT se obtuvo previamente al tratamiento quirúrgico inicial por punción aspiración con aguja fina (PAAF), estudio genético o nivel de calcitonina (CT)). El 65 % se presentó en estadios avanzados (TNM III y IV). El estudio del protoncogen RET se realizó en 162 pacientes (74 %). En el 49 % se observó mutación siendo la más frecuente (76 %) en el codón 634. La forma hereditaria más frecuentemente observada fue el síndrome de neoplasia endocrina múltiple (NEM) 2A (57 % de los casos familiares), seguida por carcinoma medular familiar (25 %) y NEM 2B (13 %). Los casos familiares tuvieron menor edad al diagnóstico y mayor frecuencia de diagnóstico prequirúrgico. Los casos índice tuvieron mayor edad al momento del diagnóstico, mayores niveles de antígeno carcinoembrionario (CEA) y CT prequirúrgicos, mayor proporción de estadios III y IV y mayor porcentaje de evidencia de enfermedad al momento de la última consulta que aquellos detectados por pesquisa. En 143 pacientes (65 %) se obtuvieron registros completos de seguimiento en los que se analizaron los factores relacionados con la evolución. La mediana de seguimiento fue de 44 meses: fallecieron 21 pacientes (14,6 %) y 122 (86 %) viven; 76 de estos (54 %) se encuentran libres de enfermedad. El grupo con evidencia de enfermedad se presentó en estadios más avanzados. Resultaron factores de mayor riesgo para evidencia de enfermedad: sexo masculino, CMT esporádico, niveles elevados de CT prequirúrgicos, estadio IV y presencia de metástasis. Los niveles de CT posquirúrgicos fueron menores en aquellos pacientes que en la evolución final no presentaron evidencia de enfermedad. El principal factor pronóstico de la evolución de los pacientes con CMT fue el estadio de presentación, determinando la importancia del diagnóstico precoz con el fin de poder implementar un tratamiento quirúrgico curativo en estadios menos avanzados.(AU)

Due to the low frequency of medullary thyroid cancer (MTC), an observational, cohort, retrospective multicenter study was conducted at the Thyroid Department of the Endocrine and Metabolism Argentine Society (SAEM). We included 219 patients with histologically proven MTC, with a mean age of 39 ± 20 yr (range 1-84 years). Sixty five percent were women and 44% were familial cases. The most common presentations were thyroid nodule (58 %) and genetic screening due to family history (22 %). In 39 % of patients, diagnosis of MTC was made by fine needle aspiration, but cytology led to surgery in 79 %. In 47 % of patients, MTC was diagnosed by cytology, calcitonin (CT) levels or genetic studies prior to initial surgery. Sixty five percent of patients had advanced stages of the disease (TNM III or IV) at diagnosis. Proto-oncogene RET was studied in 162 patients (74 %). In 49% a mutation was reported, most frequently in codon 634 (76 %). Regarding hereditary forms of MTC, MEN 2A was the most frequent (57%), followed by familial MTC in 25 % and MEN 2B in 13 % of cases. Familial cases were younger subjects and had more frequently a pre-surgery diagnosis. Index cases were older, with higher CEA and CT levels, presented in more advanced stages and had more frequently evidence of disease at final assessment than patients who were diagnosed by genetic screening. Follow-up records of 143 patients were analyzed (65%); median time was 44 months; 21 patients died (14.6 %) and 122 survived (86 %), 76 showed no evidence of disease (NED) (54 %). High risk factors for evidence of disease at the final evaluation were: male gender, sporadic MTC, higher CT pre-surgery levels, stage IV and metastasis. Post surgery CT levels were lower in patients with NED. Stage at initial diagnosis was the main prognostic factor in patients with MTC, determining the importance of early detection for performing curative surgery in less advanced stages.(AU)

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Ante la baja frecuencia del carcinoma medular de tiroides (CMT), en el Departamento de Tiroides de SAEM nos propusimos realizar un estudio de cohorte, observacional, retrospectivo y multicéntrico. Se incluyeron 219 pacientes con diagnóstico histológico de CMT. El 65 % fueron mujeres, la edad promedio fue de 39 ± 20 años (1 a 84 años); 44-% de los casos fueron familiares. Las formas de presentación más frecuentes fueron nódulo tiroideo (58 %) y pesquisa genética por antecedente familiar (22 %). Si bien la citología tiroidea fue diagnóstica de CMT en el 39 % de los casos, fue determinante de indicación quirúrgica en el 79 %. En el 47 % de los pacientes el diagnóstico de CMT se obtuvo previamente al tratamiento quirúrgico inicial por punción aspiración con aguja fina (PAAF), estudio genético o nivel de calcitonina (CT)). El 65 % se presentó en estadios avanzados (TNM III y IV). El estudio del protoncogen RET se realizó en 162 pacientes (74 %). En el 49 % se observó mutación siendo la más frecuente (76 %) en el codón 634. La forma hereditaria más frecuentemente observada fue el síndrome de neoplasia endocrina múltiple (NEM) 2A (57 % de los casos familiares), seguida por carcinoma medular familiar (25 %) y NEM 2B (13 %). Los casos familiares tuvieron menor edad al diagnóstico y mayor frecuencia de diagnóstico prequirúrgico. Los casos índice tuvieron mayor edad al momento del diagnóstico, mayores niveles de antígeno carcinoembrionario (CEA) y CT prequirúrgicos, mayor proporción de estadios III y IV y mayor porcentaje de evidencia de enfermedad al momento de la última consulta que aquellos detectados por pesquisa. En 143 pacientes (65 %) se obtuvieron registros completos de seguimiento en los que se analizaron los factores relacionados con la evolución. La mediana de seguimiento fue de 44 meses: fallecieron 21 pacientes (14,6 %) y 122 (86 %) viven; 76 de estos (54 %) se encuentran libres de enfermedad. El grupo con evidencia de enfermedad se presentó en estadios más avanzados. Resultaron factores de mayor riesgo para evidencia de enfermedad: sexo masculino, CMT esporádico, niveles elevados de CT prequirúrgicos, estadio IV y presencia de metástasis. Los niveles de CT posquirúrgicos fueron menores en aquellos pacientes que en la evolución final no presentaron evidencia de enfermedad. El principal factor pronóstico de la evolución de los pacientes con CMT fue el estadio de presentación, determinando la importancia del diagnóstico precoz con el fin de poder implementar un tratamiento quirúrgico curativo en estadios menos avanzados.

Due to the low frequency of medullary thyroid cancer (MTC), an observational, cohort, retrospective multicenter study was conducted at the Thyroid Department of the Endocrine and Metabolism Argentine Society (SAEM). We included 219 patients with histologically proven MTC, with a mean age of 39 ± 20 yr (range 1-84 years). Sixty five percent were women and 44% were familial cases. The most common presentations were thyroid nodule (58 %) and genetic screening due to family history (22 %). In 39 % of patients, diagnosis of MTC was made by fine needle aspiration, but cytology led to surgery in 79 %. In 47 % of patients, MTC was diagnosed by cytology, calcitonin (CT) levels or genetic studies prior to initial surgery. Sixty five percent of patients had advanced stages of the disease (TNM III or IV) at diagnosis. Proto-oncogene RET was studied in 162 patients (74 %). In 49% a mutation was reported, most frequently in codon 634 (76 %). Regarding hereditary forms of MTC, MEN 2A was the most frequent (57%), followed by familial MTC in 25 % and MEN 2B in 13 % of cases. Familial cases were younger subjects and had more frequently a pre-surgery diagnosis. Index cases were older, with higher CEA and CT levels, presented in more advanced stages and had more frequently evidence of disease at final assessment than patients who were diagnosed by genetic screening. Follow-up records of 143 patients were analyzed (65%); median time was 44 months; 21 patients died (14.6 %) and 122 survived (86 %), 76 showed no evidence of disease (NED) (54 %). High risk factors for evidence of disease at the final evaluation were: male gender, sporadic MTC, higher CT pre-surgery levels, stage IV and metastasis. Post surgery CT levels were lower in patients with NED. Stage at initial diagnosis was the main prognostic factor in patients with MTC, determining the importance of early detection for performing curative surgery in less advanced stages.

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OBJECTIVE: To evaluate whether germline variants of the succinate dehydrogenase genes might be phenotypic modifiers in patients with multiple endocrine neoplasia type 2. Mutations of genes encoding subunits of the succinate dehydrogenase are associated with hereditary paraganglioma/pheochromocytoma syndrome. Pheochromocytoma is one of the main manifestations of multiple endocrine neoplasia type 2 caused by germline mutation of the rearranged during transfection proto-oncogene. METHODS: Polymorphisms of the succinate dehydrogenase genes were analyzed in 77 rearranged during transfection mutation carriers, 47 patients with sporadic medullary thyroid cancer, 48 patients with sporadic Pheo, and 100 healthy individuals. Exons 10-16 of the rearranged during transfection proto-oncogene were analyzed by direct DNA sequencing, and all exons of the von Hippel-Lindau, succinate dehydrogenase B, and succinate dehydrogenase subunit D genes were tested by direct DNA sequencing and multiple ligation probe analysis. The G12S polymorphism of the succinate dehydrogenase subunit D gene was determined by restriction fragment length polymorphism. RESULTS: Of the 77 rearranged during transfection mutation carriers, 55 from 16 families had multiple endocrine neoplasia type 2A, three from three families had multiple endocrine neoplasia type 2B, and 19 from two families had familial medullary thyroid carcinoma. Eight of 55 (14.5%) patients with multiple endocrine neoplasia type 2A had this variant whereas it was absent in multiple endocrine neoplasia type 2B, familial medullary thyroid carcinoma, sporadic medullary thyroid carcinoma, and sporadic pheochromocytoma groups, and its prevalence in controls was 1% (p<0.002 multiple endocrine neoplasia type 2A versus controls). No associations between G12S and age of manifestation, incidence of pheochromocytoma or hyperparathyroidism, or level of serum calcitonin were observed. CONCLUSION: The high prevalence of the G12S variant in patients with multiple endocrine neoplasia type 2A raises questions about its role as a genetic modifier, but this proposal remains to be established.

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RESUMO

Medullary thyroid cancer (MTC) compromises 3-5 percent of all thyroid cancers and arises from parafollicular or calcitonin-producing C cells. It may be sporadic (75 percent of cases), or may occur as a manifestation of either the hereditary syndrome Multiple Endocrine Neoplasia type 2 (MEN 2A or MEN 2B) (25 percent of cases), or rarely as an isolated familial syndrome (FMTC). Complete surgical resection comprising in most cases total thyroidectomy with central lymph node dissection at an early stage of the disease is the only potential cure for MTC. The familial form of the disease, MEN-2A occupies a unique place in surgical history, having been the first disease where surgical removal of an affected organ was undertaken before the development of malignancy, solely on the basis of genetic testing. Total thyroidectomy prior to the development of invasive cancer completely avoids an otherwise lethal malignancy. Timing of prophylactic surgery is based on models that utilise genotype-phenotype correlations, which have now been stratified into three risk groups based on the specific codon involved. MTC should be followed with postoperative serial serum calcitonin levels to survey for persistent or recurrent disease as indicated by detectable levels. The challenge however, if calcitonin levels are increased, is to find the source of its production. The first localisation technique recommended would be ultrasound of the neck, since there is a high frequency of local recurrence and cervical node metastasis, followed by a total body CT scan and bone scintigraphy.

O carcinoma medular de tiróide (CMT) abrange 3-5 por cento do câncer de tiróide em geral e surge da célula parafolicular ou célula C produtora de calcitonina. Pode ser esporádico (75 por cento dos casos), ou pode ocorrer como uma das manifestações das síndromes hereditárias Neoplasia Endócrina Múltipla tipo 2 (NEM2A ou NEM2B) (25 por cento dos casos), ou mais raramente como uma síndrome familiar isolada (CMTF). A ressecção cirúrgica completa, que na maioria dos casos consiste de tireoidectomia total com dissecção dos linfonodos nos estágios precoces da doença, é a única forma de cura potencial de CMT. A forma de doença familiar da patologia NEM2A ocupa um lugar único na história da cirurgia, tendo sido a primeira doença onde a remoção cirúrgica de um órgão afetado foi realizada antes do desenvolvimento da malignidade, baseado somente no teste genético. A tireoidectomia total antes do desenvolvimento do câncer invasivo evita de outra forma a malignidade letal. A época da cirurgia profilática está baseada nos modelos que utilizam a correlação genótipo-fenótipo, que atualmente está estratificada em três grupos de risco baseado no códon envolvido. O CMT deve ser acompanhado após a cirurgia com dosagem de calcitonina sérica, cujo nível, quando detectável, indicaria a persistência ou recorrência da doença. O desafio, no entanto, se os níveis de calcitonina estão elevados, é encontrar a fonte desta produção. A primeira técnica de localização recomendada seria o ultrassom do pescoço, já que ocorre uma alta freqüência de recorrência local e de metástase dos nódulos cervicais, seguida de tomografia computadorizada do corpo inteiro e de cintilografia óssea.

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