title: The role of early 18F-FDG PET/CT in therapeutic management and ongoing risk stratification of high/intermediate-risk thyroid carcinoma.
abstract: Little is known about the role in ongoing risk stratification of fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) performed early after radioactive iodine (RAI) ablation in differentiated thyroid carcinoma (DTC). The aim of the study is to investigate whether 18F-FDG PET/CT performed early after RAI ablation is useful to detect disease and to influence therapy and ongoing risk stratification. Patients with high/intermediate risk of recurrent DTC were included. 18F-FDG PET/CT scan was performed within 6 months after RAI ablation. We confirmed results with other imaging techniques, pathology reports, or follow-up. We classified the patient response as excellent, acceptable, or incomplete. Modified Hicks criteria were used to evaluate clinical impact. We included 81 patients with high/intermediate risk of recurrent DTC. Forty-one (50.6%) had positive uptake in 18F-FDG PET/CT, with negative (131)I whole-body scan ((131)I WBS). Sensitivity, specificity, and diagnostic accuracy of 18F-FDG PET/CT were 92.5, 90.2, and 91.4%, respectively. 18F-FDG PET/CT results had an impact on therapy in 38.3% of patients. One year after initial therapy, 45.7% showed excellent response, 8.6% acceptable response, and 45.7% incomplete response. A statistically significant relationship was found between negative 18F-FDG PET/CT and excellent response (80 vs. 12.2%, p < 0.001; OR 52.8). 18F-FDG PET/CT scan performed early in surveillance of patients with high/intermediate-risk thyroid carcinoma provides important additional information not available with conventional follow-up methods and had a high impact on therapy. A negative 18F-FDG PET/CT predicts an excellent response to therapy in the new ongoing risk stratification.
authors.affiliation: Department of Nuclear Medicine, Virgen de las Nieves University Hospital, Granada, Spain. eva_gor@hotmail.com.
authors.forename: E M
authors.initials: EM
authors.lastname: Triviño Ibáñez
authors.affiliation: Department of Nuclear Medicine, Virgen de las Nieves University Hospital, Granada, Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Muros
authors.affiliation: Department of Endocrinology and Metabolism, San Cecilio University Hospital, Granada, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Torres Vela
authors.affiliation: Department of Nuclear Medicine, Virgen de las Nieves University Hospital, Granada, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Llamas Elvira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003131:Combined Modality Therapy; D019468:Disease Management; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000008:administration & dosage; D006801:Humans; D008197:Lymph Node Excision; D008297:Male; D008875:Middle Aged; D000072078:Positron Emission Tomography Computed Tomography; D011446:Prospective Studies; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D015203:Reproducibility of Results; D018570:Risk Assessment; D013963:Thyroid Hormones / Q000097:blood; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000628:therapy*; D013965:Thyroidectomy; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D013963:Thyroid Hormones; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG PET/CT; Differentiated thyroid carcinoma; High/intermediate-risk thyroid carcinoma; Therapeutic management