Diagnostic utility of PET/CT with 18F-DOPA and 18F-FDG in persistent or recurrent medullary thyroid carcinoma: the importance of calcitonin and carcinoembryonic antigen cutoff

• Published in: European journal of nuclear medicine and molecular imaging Vol. 44; no. 12; pp. 2004 - 2013
• Main Authors: Romero-Lluch, Ana Reyes, Cuenca-Cuenca, Juan Ignacio, Guerrero-Vázquez, Raquel, Martínez-Ortega, Antonio Jesús, Tirado-Hospital, Juan Luis, Borrego-Dorado, Isabel, Navarro-González, Elena
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2017; Springer Nature B.V
• Subjects: Antigens; Calcitonin; Carcinoembryonic antigen; Cardiology; Computed tomography; Correlation analysis; Diagnostic systems; Dihydroxyphenylalanine; Imaging; Lesions; Medical diagnosis; Medical imaging; Medicine; Medicine & Public Health; Nuclear Medicine; Oncology; Original Article; Orthopedics; Patients; Positron emission; Positron emission tomography; Radiology; Reliability analysis; Sensitivity; Thyroid cancer; Thyroid carcinoma; Tomography; recurrence; F-FDG; Medullary thyroid carcinoma; F-DOPA; PET/CT
• ISSN: 1619-7070; 1619-7089
• DOI: 10.1007/s00259-017-3759-4

Purpose This study sought to evaluate and compare the utility of 18-F-fluorodihydroxyphenylalanine ( 18 F-DOPA) and 18-F-fluorodeoxyglucose ( 18 F-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 18 F-DOPA PET/CT). Methods We prospectively recruited 18 patients with recurrent MTC, identified by elevation of Ct or CEA. Each patient underwent a 18 F-FDG PET/CT and a 18 F-DOPA PET/CT. Results Abnormal uptakes were detected with 18 F-DOPA (n=12) and 18 F-FDG (n=9), (sensitivity of 66.7% vs. 50%; p <0.01). Twenty-eight lesions were detected with 18 F-DOPA vs. 16 lesions with 18 F-FDG (1.56±1.5 vs. 0.89±1.18 lesions per patient; p =0.01). None of our patients showed additional lesions with 18 F-FDG in comparison to 18 F-DOPA. Patient-based detection rate increased significantly with Ct levels ≥150 pg/mL vs. Ct<150 pg/mL for both 18 F-DOPA (sensitivity 90.9% vs. 28.6%; p =0.013) and 18 F-FDG PET/CT (sensitivity 72.7% vs. 14.3%; p =0.025). Using a CEA cutoff of ≥5 ng/mL, detection rates of 18 F-DOPA and 18 F-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 18 F-DOPA PET/CT appears to be superior to 18 F-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.