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.
Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, St. Louis, MO 63110, USA.
Amber L
AL
Traugott
Farrokh
F
Dehdashti
Kathryn
K
Trinkaus
Mark
M
Cohen
Elizabeth
E
Fialkowski
Frank
F
Quayle
Hameda
H
Hussain
Rosa
R
Davila
Lourdes
L
Ylagan
Jeffrey F
JF
Moley
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