Exclusion of malignancy in thyroid nodules with indeterminate fine-needle aspiration cytology after negative 18F-fluorodeoxyglucose positron emission tomography: interim analysis.
BACKGROUND
In all, 20% of fine-needle aspiration (FNA) biopsies of thyroid nodules have an indeterminate diagnosis; of these, 80% are found to be benign after thyroidectomy. Some previous reports indicate that positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) imaging may predict malignancy status. We now report results on the first 51 patients in the largest prospective study of FDG-PET in patients with an indeterminate thyroid nodule FNA.


METHODS
Eligible patients had a dominant thyroid nodule that was palpable or >or=1 cm in greatest dimension as seen by ultrasonography, and indeterminate histology of the FNA biopsy specimen. Participants underwent preoperative neck FDG-PET alone or FDG-PET with computed tomography (FDG-PET/CT). Images were evaluated qualitatively and semiquantitatively using the maximum standardized uptake value (SUV(max)). Final diagnosis was determined by histopathologic analysis after thyroidectomy. Descriptive statistical analysis was performed.


RESULTS
A total of 51 patients underwent preoperative FDG-PET or FDG-PET/CT. Studies without focally increased uptake localized to the lesion were considered negative. For all lesions (10 malignant, 41 benign), the sensitivity, specificity, positive-predictive value (PPV), and negative-predictive value (NPV) were 80%, 61%, 33%, and 93%, respectively. Postoperatively, two malignant and six benign lesions were found to be <1 cm by pathology examination; one lesion was not measured. When these lesions were excluded, the sensitivity, specificity, PPV, and NPV were 100%, 59%, 36%, and 100%, respectively.


CONCLUSIONS
Based on these preliminary data, FDG-PET may have a role in excluding malignancy in thyroid nodules with an indeterminate FNA biopsy. This finding justifies ongoing accrual to our target population of 125 participants.
Traugott
Amber L
AL
Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
Dehdashti
Farrokh
F
Trinkaus
Kathryn
K
Cohen
Mark
M
Fialkowski
Elizabeth
E
Quayle
Frank
F
Hussain
Hameda
H
Davila
Rosa
R
Ylagan
Lourdes
L
Moley
Jeffrey F
JF
D000328:Adult; D000368:Aged; D044963:Biopsy, Fine-Needle / Q000379:methods*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D016606:Thyroid Nodule / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18