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PURPOSE: This study sought to evaluate and compare the utility of 18-F-fluorodihydroxyphenylalanine (18F-DOPA) and 18-F-fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) for identification of lesions in patients with recurrent medullary thyroid carcinoma (MTC). In addition, we analyzed the correlation between the calcitonin (Ct), carcinoembryonic antigen (CEA) levels, each doubling time (DT), and PET positivity. We evaluated the reliability of the 150 pg/mL Ct cutoff set by the American Thyroid Association guidelines for further imaging (including 18F-DOPA PET/CT). METHODS: We prospectively recruited 18 patients with recurrent MTC, identified by elevation of Ct or CEA. Each patient underwent a 18F-FDG PET/CT and a 18F-DOPA PET/CT. RESULTS: Abnormal uptakes were detected with 18F-DOPA (n=12) and 18F-FDG (n=9), (sensitivity of 66.7% vs. 50%; p<0.01). Twenty-eight lesions were detected with 18F-DOPA vs. 16 lesions with 18F-FDG (1.56±1.5 vs. 0.89±1.18 lesions per patient; p=0.01). None of our patients showed additional lesions with 18F-FDG in comparison to 18F-DOPA. Patient-based detection rate increased significantly with Ct levels ≥150 pg/mL vs. Ct<150 pg/mL for both 18F-DOPA (sensitivity 90.9% vs. 28.6%; p=0.013) and 18F-FDG PET/CT (sensitivity 72.7% vs. 14.3%; p=0.025). Using a CEA cutoff of ≥5 ng/mL, detection rates of 18F-DOPA and 18F-FDG PET/CT were 81.1% and 72.7%, respectively. No correlation between Ct-DT or CEA-DT and PET positivity was found. Histological confirmation was obtained in eight patients. CONCLUSIONS: 18F-DOPA PET/CT appears to be superior to 18F-FDG PET/CT in detecting and locating lesions in patients with recurrent MTC. This technique tends to be especially useful in patients with negative results in other imaging modalities and Ct≥150 pg/mL or CEA≥5 ng/mL.
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Calcitonina/sangue , Antígeno Carcinoembrionário/sangue , Carcinoma Neuroendócrino/sangue , Carcinoma Neuroendócrino/diagnóstico por imagem , Di-Hidroxifenilalanina/análogos & derivados , Fluordesoxiglucose F18 , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Neoplasias da Glândula Tireoide/sangue , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Adulto , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Recidiva , Padrões de Referência , Adulto JovemRESUMO
INTRODUCTION: Thyroid nodules are a common finding. A high-resolution thyroid nodule clinic (HR-TNC) condenses all tests required for the evaluation of thyroid nodules into a single appointment. We aimed to evaluate the clinical outcomes at HR-TNCs. DESIGN AND METHODS: A retrospective cross-sectional multicenter study including data from four HR-TNCs in Spain. We evaluated fine-needle aspiration (FNA) indications and the association between clinical and ultrasound characteristics with cytological and histopathological outcomes. RESULTS: A total of 2809 thyroid nodules were included; FNA was performed in 82.1%. Thyroid nodules that underwent FNA were more likely larger, isoechoic, with microcalcifications, and in younger subjects. The rate of nondiagnostic FNA was 4.3%. A solid component, irregular margins or microcalcifications, significantly increased the odds of Bethesda IV-V-VI (vs. Bethesda II). Irregular margins and a solid component were independently associated with increased odds of malignancy. Thyroid nodules <20 mm and ≥20-<40 mm had a 6.5-fold and 3.3-fold increased risk for malignancy respectively in comparison with those ≥40 mm. CONCLUSION: In this large multicenter study, we found that the presence of a solid component and irregular margins are factors independently related to malignancy in thyroid nodules. Since nodule size ≥40 mm was associated with the lowest odds of malignancy, this cut-off should not be a factor leading to indicate thyroid surgery. HR-TNCs were associated with a low rate of nondiagnostic FNA.
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Humanos , Neoplasias das Paratireoides/cirurgia , Paratireoidectomia/efeitos adversos , Fasciite/etiologia , Fatores de RiscoRESUMO
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