18F-fluorodeoxyglucose positron emission tomography-computed tomography for suspected recurrent papillary thyroid cancer: early experience at Sunnybrook Health Sciences Centre.
OBJECTIVE
To report the initial experience with combined 18F-fluorodeoxyglucose positron emission tomography (FDG PET)/computed tomography (CT) imaging for suspected recurrent papillary differentiated thyroid cancer (DTC) at Sunnybrook Health Sciences Centre (SHSC), Toronto.


METHODS
Single institution retrospective study.


METHODS
Consecutive patients from SHSC who underwent FDG PET/CT imaging for suspected recurrent DTC over a period of 2.5 years were identified and their charts reviewed.


METHODS
Qualitative appraisal of FDG PET/CT imaging in suspected recurrent DTC.


RESULTS
Sixteen patients (14F, 2M) were identified accounting for 17 FDG PET/CT scans. Three scans (18%) in 3 different patients were reported as suspicious for recurrent disease in the neck (1-3 lesions) and were considered "positive". All were subsequently confirmed pathologically (4-13 positive lymph nodes post operatively). Prior conventional imaging was abnormal in two patients. Two patients had an elevated non-stimulated thyroglobulin (TG) < 10 ng/mL (4.9 and 9.4). The remaining patient had a TG < 0.3 ng/mL but was anti-TG antibody positive (84 IUx10-3/L). With a median follow up of 15 months (range 7-36) there were no false positive or negative scans. Incidental pathology (breast cancer, large bowel polyps) was identified on a further 2/17 scans (12%).


CONCLUSIONS
FDG PET/CT imaging is able to detect recurrent DTC in patients with low TG levels. It can complement conventional imaging findings and exclude distant FDG-avid metastases prior to surgery. It may underestimate the number of positive lymph nodes in the neck. Occult pathology may be identified with whole body FDG PET/CT.
Dahele
Max
M
Departmentof Radiation Oncology, University of Toronto, Edmond Odette Cancer Centre,Toronto, Ontario.
Ung
Yee C
YC
Ehrlich
Lisa
L
Silverberg
Jay
J
Balogh
Judith
J
Wong
C Shun
CS
D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D002173:Cancer Care Facilities; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D015331:Cohort Studies; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D009367:Neoplasm Staging; D009864:Ontario; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
D015415:Biomarkers; D019788:Fluorodeoxyglucose F18; D013954:Thyroglobulin