Utility of fluorine-18-fluorodeoxyglucose positron emission tomography in differentiated thyroid carcinoma with negative radioiodine scans and elevated serum thyroglobulin levels
Ma. Muros et al., Utility of fluorine-18-fluorodeoxyglucose positron emission tomography in differentiated thyroid carcinoma with negative radioiodine scans and elevated serum thyroglobulin levels, AM J SURG, 179(6), 2000, pp. 457-461
BACKGROUND: This study aimed to determine the role of fluorine-18-fluorodeo
xyglucose positron emission tomography (FDG-PET) in the follow-up of patien
ts who underwent total thyroidectomy and iodine-131 (I-131) ablation therap
y for differentiated thyroid cancer and presented increased thyroglobulin l
evels with negative I-131 and thallium-201 (Tl-201) scans.
METHODS: Two patients with follicular carcinoma and eight with papillary tu
mors underwent total thyroidectomy and I-131 therapy until the I-131 scan w
as negative. I-131 and Tl-201 scans were performed with negative results in
all cases, while serum thyroglobulin measurements were all positive with n
egative thyroglobulin autoantibodies. One week after the I-131 scans, all t
he patients underwent FDG-PET whole-body scans.
RESULTS: The FDG-PET scan detected in 4 patients, a single focal increase o
f FDG uptake in one lymph node metastasis (subsequently confirmed histologi
cally); in 1 patient, multiple pathological focal uptakes in brain, neck, a
nd chest; and in 1 patient, two mild focal uptakes in the mediastinum, clos
e to the tracheal branch, In 2 other patients, pathological FDG uptakes in
cervical spine and mediastinum were not confirmed by other imaging techniqu
es, and in the 2 remaining patients the scan results were inconclusive. The
sensitivity of FDG-PET whole-body scan for detecting metastatic thyroid ca
ncer was 60%.
CONCLUSIONS: This study indicates that the FDG-PET whole-body scan is a use
ful tool in the follow-up of patients with differentiated thyroid cancer, n
egative I-131 and Tl-201 scans and elevated serum thyroglobulin levels. The
FDG-PET scan detects metastatic disease in 60% of patients with differenti
ated thyroid cancer, enabling surgical therapy to be performed on accessibl
e lesions. (C) 2000 by Excerpta Medica, Inc.