Multifocal growth is characteristic of hereditary medullary thyroid cancer (MTC), whereas origin and impact of multifocal growth is enigmatic for sporadic MTC. To address this, 460 RET-negative patients with sporadic MTC, stratified by 1 (93.3 %), 2 (5.7 %) and 3 (1.1 %) thyroid tumor foci, were compared with 219 RET-positive patients with hereditary MTC, stratified by 1 (38.4 %), 2 (45.7 %), 3 (6.4 %), 4 (6.8 %) and ≥5 (2.7 %) thyroid tumor foci. For sporadic MTC, significant associations were identified with bilateral thyroid lobe involvement, microscopic lymphatic invasion, extrathyroid extension, node and distant metastases, number of node metastases, preoperative basal calcitonin level, and decreasing biochemical cure. For hereditary MTC, significant associations were limited to bilateral thyroid lobe involvement, largest thyroid tumor diameter, and preoperative basal calcitonin level. In sporadic MTC, multifocal growth is due to lymphatic invasion with frequent node metastases, whereas in hereditary MTC, it reflects malignant progression from C-cell hyperplasia to cancer.

BACKGROUND: Detectable, and especially rising post-thyroidectomy serum calcitonin and Carcinoembryonic Antigen (CEA) levels, as per American Thyroid Association (ATA) guidelines, indicate potential disease presence, requiring frequent calcitonin measurement or imaging for early detection of persistent or recurrent Medullary Thyroid Carcinoma (MTC). Thus, defining the clinical cutoff value of detection of calcitonin assays relative to imaging and clinical status is crucial for patient care. This study aimed to evaluate postoperative calcitonin levels using the new Siemens Atellica assay system to determine the most appropriate levels for clinical decision-making.
METHODS: A retrospective analysis was conducted using Siemens Atellica for calcitonin testing on 56 samples from 40 patients between 09/27/2022 and 08/11/2023. Only calcitonin results performed at least 3 months post-total thyroidectomy were included. Imaging studies, within 6 months of the calcitonin report, were assessed. CEA results were also reviewed.
RESULTS: Precision analysis at 2.94 and 5.24 pg/mL revealed coefficients of variation (CVs) at 16.49% and 8.87%, respectively. For the evidence of post-total thyroidectomy persistent or recurrent MTC confirmed by imaging, using a 1.89 pg/mL cutoff for calcitonin yielded 43% sensitivity and 67% specificity. Using a 5.00 pg/mL cutoff resulted in 0% sensitivity and 100% specificity.
CONCLUSIONS: Our findings indicate the potential suitability of a 5 pg/mL calcitonin cutoff on the Siemens Atellica platform for evaluating tumor persistence or recurrence in post-thyroidectomy patients in our institution. However, individual laboratories should establish their own clinical cutoff value when evaluating calcitonin levels for monitoring tumor recurrence post-thyroidectomy.

UNASSIGNED: Lateral lymph node metastasis (LLNM) is very common in medullary thyroid carcinoma (MTC), but there is still controversy about how to manage cervical lateral lymph nodes, especially for clinically negative MTC. The aim of this study is to develop and validate a nomogram for predicting LLNM risk in MTC.
UNASSIGNED: A total of 234 patients from two hospitals were retrospectively enrolled in this study and divided into LLNM positive group and LLNM negative group based on the pathology. The correlation between LLNM and preoperative clinical and ultrasound variables were evaluated by univariable and multivariable logistic regression analysis. A nomogram was generated to predict the risk of the LLNM of MTC patients, validated by external dataset, and evaluated in terms of discrimination, calibration, and clinical usefulness.
UNASSIGNED: The training, internal, and external validation datasets included 152, 51, and 31 MTC patients, respectively. According to the multivariable logistic regression analysis, gender (male), relationship to thyroid capsule and serum calcitonin were independently associated with LLNM in the training dataset. The predictive nomogram model developed with the aforementioned variables showed favorable performance in estimating risk of LLNM, with the area under the ROC curve (AUC) of 0.826 in the training dataset, 0.816 in the internal validation dataset, and 0.846 in the external validation dataset.
UNASSIGNED: We developed and validated a model named MTC nomogram, utilizing available preoperative variables to predict the probability of LLNM in patients with MTC. This nomogram will be of great value for guiding the clinical diagnosis and treatment process of MTC patients.

BACKGROUND: Graves\' disease (GD) is an autoimmune disorder affecting the thyroid gland, leading to systemic manifestations such as hyperthyroidism, Graves\' orbitopathy, and pretibial myxedema. Contrary to previous beliefs that hyperthyroidism protects against thyroid cancer, recent studies reveal an increased incidence of thyroid malignancies in GD patients, particularly differentiated thyroid carcinomas and, in rare cases, medullary thyroid carcinoma (MTC).
METHODS: This case series presents three female GD patients diagnosed with MTC, highlighting the complexities of diagnosis and management. All patients exhibited thyroid nodules with suspicious ultrasonographic features, elevated plasma calcitonin levels, and required total thyroidectomy. Histological examination confirmed MTC.
CONCLUSIONS: These cases underscore the importance of routine calcitonin screening in GD patients with thyroid nodules to facilitate early detection and improve prognosis. Our findings suggest that while the coexistence of GD and MTC is likely incidental, vigilant monitoring and comprehensive evaluation are crucial for timely intervention.
CONCLUSIONS: This study advocates for integrating calcitonin testing into the standard diagnostic protocol for GD patients presenting with thyroid abnormalities.

Aim: Tumor markers often remain elevated after intended curative resection of medullary thyroid carcinoma (MTC). The aim of this study was to determine the expression of αvβ3, a promising theranostics target, in MTC and its metastases. Materials & methods: Avβ3 expression was analyzed in 104 patients using a tissue microarray and correlated with clinicopathological variables and survival. Results: Cytoplasmic αvβ3 positivity was seen in 70 patients and was associated with lymph node metastases at time of initial surgery. Membranous positivity was considered positive in 30 patients and was associated with sporadic MTC. Conclusion: Avβ3 was expressed in the cytoplasm of 67% of MTC patients. Membranous expression, which is presumably most relevant for the theranostic use of αvβ3, was seen in 29%.
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Medullary thyroid carcinoma (MTC) can often have an indolent course despite distant metastatic disease. Additionally, given that metastatic MTC is incurable and systemic therapies have non-negligeable toxicities, localized treatments are often favored in presence of oligo-progressive disease. Transarterial radioembolization (TARE) with yttrium-90 (Y90) has emerged as a safe and efficacious treatment for nonresectable primary and metastatic liver tumors, yet data supporting its use in metastatic MTC are limited. We present the case of a patient with hereditary MTC and large bilobar liver metastases who demonstrated tumor response and resolution of their paraneoplastic diarrhea following TARE with Y90 microspheres.

Few studies have investigated the impact of primary tumor resection (PTR) on patients with distant metastasis medullary thyroid carcinoma (DMMTC). This population-based study aims to assess the application of PTR in DMMTC patients, ascertain its benefits, and identify optimal surgical indications. DMMTC Patients diagnosed between 2010 and 2020 were included through the Surveillance, Epidemiology, and End Results (SEER) program. Logistic regression analysis identified driving factors of surgical decision-making. Propensity score matching (PSM), Kaplan-Meier method, and Cox regression were utilized to compare overall survival (OS) and disease-specific survival (DSS) between surgical and non-surgical groups. Subgroup analyses were performed to determine optimal surgical indications. Of 238 DMMTC patients included, 122 (51.3%) patients underwent PTR. Extrathyroidal extension and N1 stage emerged as independent factors promoting the surgical decision. PSM-adjusted survival analyses revealed significant advantages in both OS and DSS for the surgical group. Moreover, subgroup analyses indicated that except for patients aged ≥ 65 years, tumors ≤ 20 mm, or with multiple metastasized sites (> 1), the others significantly benefit from PTR. PTR significantly improves prognosis in selected DMMTC patients. The decision to undergo PTR in other patients should be based on a comprehensive assessment of the disease, surgeon\'s experience, and family discussions for potential survival benefits.

UNASSIGNED: Medullary thyroid carcinoma (MTC) is an uncommon thyroid cancer with limited treatment options for advanced disease. A small subset exhibits mixed MTC histology with both medullary and well-differentiated components. We investigated survival outcomes with systemic therapy in isolated versus mixed MTC using a large population-based cohort.
UNASSIGNED: Patients diagnosed with MTC from 2000 to 2019 were identified in the National Cancer Institute\'s Surveillance, Epidemiology, and End Results database. The overall and thyroid cancer-specific survivals were compared between isolated (n = 1814) and mixed (n = 113) MTC cohorts. The impact of postoperative systemic therapy on survival was analyzed.
UNASSIGNED: No significant difference in 10-year overall survival was observed between isolated (77.4 %) and mixed (75.2 %) MTC in a cohort of 1927 patients. Median overall survival was similar between isolated (136.9 months) and mixed MTC (129.0 months), p = 0.81. While systemic therapy improved 10-year survival in isolated MTC (83.2 % vs. 76.9 %, p < 0.001), no benefit was seen in mixed MTC (76.4 % vs. 74.2 %, p = 0.82). Multivariate analysis confirmed survival gains with systemic therapy for isolated (HR = 0.763, 95%CI = 0.590-0.987, p = 0.040) but not mixed MTC (HR = 0.909, 95%CI = 0.268-3.079, p = 0.88).
UNASSIGNED: In this large population-based study, no significant survival difference was observed between isolated and mixed MTC. Systemic therapy was associated with improved survival in isolated MTC, but not in the mixed subtype. These findings suggest a differential treatment response that warrants further investigation in prospective studies and may inform histology-tailored management strategies for mixed MTC.

BACKGROUND: Calcitonin is a sensitive marker for medullary thyroid carcinoma (MTC) diagnosis and postsurgical follow-up. This study aimed to define the gender and tumor size-specific calcitonin cutoff values for diagnosing MTC.
METHODS: This retrospective study recruited 95 MTC patients and 10,523 non-MTC patients who underwent thyroid nodule surgery at Zhongshan Hospital between January 2015 and June 2023. Receiver operating characteristic (ROC) curves were used to assess calcitonin cutoff values for diagnosing MTC.
RESULTS: Calcitonin levels in non-MTC patients were influenced by gender, CKD stage and age, with gender being the highest ranked predictor. In MTC patients, calcitonin levels were associated with tumor diameter, lymph node metastasis, and TNM stage. In the entire study population, calcitonin cutoff values to diagnose MTC were 17.75 pg/mL for males (sensitivity: 97.60%, specificity: 99.40%) and 7.15 pg/mL for females (sensitivity: 94.34%, specificity: 99.22%). In patients with a thyroid nodule diameter ≤10 mm, the calcitonin cutoff values to diagnose MTC were 17.50 pg/mL for males (sensitivity: 95.00%, specificity: 99.27%) and 7.15 pg/mL for females (sensitivity: 90.91%, specificity: 99.04%). In patients with a thyroid nodule diameter >10 mm, the calcitonin cutoff values to diagnose MTC were 104.80 pg/mL for males (sensitivity: 100.00%, specificity: 100.00%) and 32.60 pg/mL for females (sensitivity: 96.77%, specificity: 100.00%).
CONCLUSIONS: We have identified the gender and tumor size-specific cutoff values for the diagnosis of MTC. Cutoff values based on gender and tumor diameter may help to improve the accuracy of preoperative diagnosis of MTC, which is worth to be verified by future studies.

A man, in his 30s, with a history of obesity and hypothyroidism planned to begin taking a new Glucagon-like peptide-1 (GLP-1) agonist for weight loss. As these medications have been associated with C-cell hyperplasia, a calcitonin level was checked as evaluation prior to starting the drug. This returned at 131 pg/mL (upper limit of normal<10 pg/mL), and a subsequent carcinoembryonic antigen was 5.2 ng/mL (ref<3 ng/mL). Thyroid ultrasound was performed and demonstrated bilateral subcentimeter nodules. After total thyroidectomy, final pathology demonstrated bilateral 0.8 cm medullary thyroid carcinoma. Genetic testing revealed a NM_020975.6: c.1826G > A; p.Cys609Tyr. germline RET mutation, confirming the diagnosis of multiple endocrine neoplasia 2 syndrome. The patient recovered well from treatment. His first-degree relatives also underwent genetic testing. This case represents a surprising diagnosis of familial multiple endocrine neoplasia 2A prior to starting a Glucagon-like peptide-1 agonist.