PET-CT scans in recurrent or persistent differentiated thyroid cancer: Is there added utility beyond conventional imaging?

Department of Surgery, University of Iowa Hospitals and Clinics, Iowa City, Iowa 52242, USA.
Surgery (Impact Factor: 3.38). 12/2010; 148(6):1082-9; discussion 1089-90. DOI: 10.1016/j.surg.2010.09.015
Source: PubMed


Integrated positron emission tomography (PET)-computed tomography (CT) may have advantages over conventional imaging in localizing recurrent or persistent differentiated thyroid cancer.
A retrospective review of patients who underwent PET-CT scans was performed. Results were compared with contrast CT, magnetic resonance imaging, ultrasonography, and radioactive iodine (RAI) scans.
Thirty patients (mean age, 49.9 ± 17 years) underwent 36 PET-CT scans, mostly for elevated thyroglobulin levels and negative RAI scans (30 scans). Fifty percent (18/36) of PET-CT scans showed increased uptake in the neck, 11 of 36 (31%) in the chest, 3 of 36 (8.3%) in bone, and 6 of 36 (16.6%) in other areas. PET-CT had overall sensitivity, specificity, and positive predictive values of 73.9%, 61.5%, and 77.3% respectively. To assess the added value of PET-CT, we focused on the 21 scans performed after conventional imaging in 20 patients. PET-CT provided additional information in 2 (10%) patients, both of whom were spared interventions. However, PET-CT underestimated extent of disease in 3 (15%) patients and led to unnecessary interventions in 3 (15%) additional patients.
PET-CT has reasonable sensitivity in the detection of recurrent thyroid cancer. However, the added value of PET-CT may be seen only in a limited number of patients after good quality, conventional imaging. Further studies are needed to determine the most cost-effective approach to managing these patients.

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    • "They found FDG-PET/CT provided additional information in only 2/20 (10.0%) patients, both of whom required no additional intervention, but underestimated the extent of disease in 3/30 (15.0%) patients and led to unnecessary interventions (including surgery, RAI, and antibiotics) in 3/30 (15.0%) additional patients. They concluded that FDG-PET/CT has a good sensitivity in detecting recurrent or persistent DTC, but the added value over good-quality conventional imaging is very limited [44]. Furthermore, it may lead to unnecessary interventions [44]. "
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    Journal of Thyroid Research 01/2012; 2012(5):198313. DOI:10.1155/2012/198313
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    The Oncologist 03/2011; 16(4):458-66. DOI:10.1634/theoncologist.2010-0256 · 4.87 Impact Factor
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    ABSTRACT: Fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) is able to localize persistent or recurrent disease in differentiated thyroid carcinoma (DTC). The aim of the study was to correlate PET/CT results with precise intraoperative localization of persistent or recurrent papillary and follicular thyroid carcinoma. Patients with differentiated thyroid carcinoma who received FDG-PET scans were prospectively documented. The PET/CT results were correlated with other localization studies (neck ultrasound, 131I whole-body scan) and accurately compared to intraoperative findings and histopathological examinations. FDG-PET/CT scans were performed in 18 patients, between 16 and 84 years of age, from December 2008 to June 2011. Fourteen patients had papillary thyroid carcinomas and 4 had follicular thyroid carcinomas. All patients had a previous thyroidectomy and radioiodine ablation. Before cervical re-exploration, FDG-PET/CT-positive findings were reported in 14 individuals, whereas 4 PET scans provided no evidence of disease. Intraoperatively, 13 of 14 FDG-PET/CT-positive localizations of recurrent or persistent thyroid carcinomas were verified and confirmed by histopathology (sensitivity 93%). In another patient lymph node metastases of lung cancer were detected intraoperatively. However, FDG-PET/CT underestimated the number of lesions in 5 of 6 patients undergoing systematic lymphadenectomy. No lymph node or soft tissue metastases were found intraoperatively in 3 of the 4 patients with negative FDG-PET scans. A solitary cystic lymph node metastasis was found in the fourth patient but was not detected by FDG-PET/CT (specificity 75%). FDG-PET/CT has high sensitivity and specificity for the detection of persistent or recurrent differentiated thyroid carcinoma. FDG-PET/CT helps to select patients who might benefit from surgery because it provides precise anatomical details.
    Hormone and Metabolic Research 07/2012; 44(12). DOI:10.1055/s-0032-1316351 · 2.12 Impact Factor
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