Sensitivity and prognostic value of positron emission tomography with F-18-fluorodeoxyglucose and sensitivity of immunoscintigraphy in patients with medullary thyroid carcinoma treated with anticarcinoembryonic antigen-targeted radioimmunotherapy.
BACKGROUND
Patients with progressive medullary thyroid carcinoma (MTC) undergo multiple imaging procedures for diagnosis of relapse and staging.


OBJECTIVE
Our objective was to assess the sensitivity and prognostic value of 18F-2-fluoro-2-deoxy-d-glucose (FDG) positron emission tomography (PET)/computed tomography (CT), and the imaging sensitivity of pretargeted iodine-131-radioimmunotherapy (RIT) in patients with progressive MTC.


METHODS
We performed a prospective multicenter study in high-risk patients with rapidly progressing MTC enrolled in a phase-II pretargeted RIT study, as documented by short serum calcitonin (Ct) or carcinoembryonic antigen (CEA) doubling time (DT). INTERVENTIONS/MAIN OUTCOME MEASURES: Patients underwent neck-thoracic-abdominal CT, spine and pelvic magnetic resonance imaging, whole-body post-RIT immunoscintigraphy (IS) with iodine-131, and whole-body 18F-FDG-PET/CT imaging. Imaging sensitivity and the correlation between FDG uptake and biomarkers DT were evaluated.


RESULTS
A total of 33 patients with mean CEA and Ct DTs of 1.90 yr (range 0.21-8.50) and 1.52 yr (range 0.09-6.01), respectively, were evaluated. Sensitivity of FDG-PET/CT was 83% for neck, 85% for mediastinal, 75% for lung, 60% for liver, and 67% for bone metastases; overall sensitivity was 76%. Median standardized uptake value (SUVmax) was 5.23 (2.06-13.90). SUVmax correlated significantly with Ct DT (P = 0.011) and minimal DT (minimal value between CEA DT and Ct DT) (P = 0.027). Overall sensitivity of post-RIT IS, CT, and bone magnetic resonance imaging were 94, 74, and 85%, respectively.


CONCLUSIONS
These results demonstrate the value of FDG-PET/CT for staging of patients with progressive MTC, especially in the neck and mediastinum, with possible prognostication by SUV quantification. Post-RIT IS was the most sensitive of the imaging modalities studied prospectively.
Oudoux
Aurore
A
Nuclear Medicine, University Hospital, 44093 Nantes, France.
Salaun
Pierre-Yves
PY
Bournaud
Claire
C
Campion
Loïc
L
Ansquer
Catherine
C
Rousseau
Caroline
C
Bardet
Stéphane
S
Borson-Chazot
Françoise
F
Vuillez
Jean-Philippe
JP
Murat
Arnaud
A
Mirallié
Eric
E
Barbet
Jacques
J
Goldenberg
David M
DM
Chatal
Jean-François
JF
Kraeber-Bodéré
Françoise
F
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D001842:Bone and Bones / Q000000981:diagnostic imaging; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D018276:Carcinoma, Medullary / Q000000981:diagnostic imaging* / Q000276:immunology*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007457:Iodine Radioisotopes; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D016719:Radioimmunodetection; D016499:Radioimmunotherapy; D019275:Radiopharmaceuticals; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000276:immunology*; D014055:Tomography, Emission-Computed
D015415:Biomarkers; D002272:Carcinoembryonic Antigen; D007457:Iodine Radioisotopes; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18