title: Prevalence and risk of cancer of focal thyroid incidentaloma identified by 18F-fluorodeoxyglucose positron emission tomography for metastasis evaluation and cancer screening in healthy subjects.
abstract: We performed a retrospective review of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) examination to determine the prevalence of thyroid FDG-PET incidentaloma in a patient group evaluated for metastasis of cancer and in a group of healthy subjects who underwent voluntary cancer screening. We also evaluated the risk of malignancy in focal thyroid FDG-PET incidentaloma and its association with standard uptake values (SUVs) (maximum and greater than 0.75 threshold). A total of 1330 subjects underwent FDG-PET for metastasis evaluation (n = 999) and cancer screening (n = 331). Twenty-nine of 1330 subjects (2.2%) showed focal (n = 21) or diffuse (n = 8) thyroid FDG-PET incidentaloma. There was no significant difference in the prevalence of thyroid FDG-PET incidentaloma between the two groups (19 of 999 vs. 10 of 331; P > 0.05). Four of 15 focal incidentalomas (26.7%) whose histological diagnoses were available showed papillary thyroid cancer. The maximum SUV (16.5 +/- 4.70) and greater than 0.75 threshold SUV (14.2 +/- 5.3) of malignant lesions were significantly higher than those of benign tumors (6.5 +/- 3.8 and 4.9 +/- 3.0; P < 0.05). In conclusion, thyroid FDG-PET incidentaloma has prevalence of 2.2%, and its prevalence was not different according to the purpose of the FDG-PET. The focal thyroid FDG-PET incidentaloma carries a high risk of malignancy, especially in cases with high SUVs. Therefore, focal thyroid FDG-PET incidentaloma with high SUVs warrants a pathological diagnostic procedure if it changes a patient's treatment plan or prognosis.
authors.affiliation: Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi 411-764, Republic of Korea.
authors.forename: Keon Wook
authors.initials: KW
authors.lastname: Kang
authors.forename: Seok-Ki
authors.initials: SK
authors.lastname: Kim
authors.forename: Han-Sung
authors.initials: HS
authors.lastname: Kang
authors.forename: Eun Sook
authors.initials: ES
authors.lastname: Lee
authors.forename: Jung Suk
authors.initials: JS
authors.lastname: Sim
authors.forename: In Goo
authors.initials: IG
authors.lastname: Lee
authors.forename: Seung-Yong
authors.initials: SY
authors.lastname: Jeong
authors.forename: Sun Wook
authors.initials: SW
authors.lastname: Kim
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000000981:diagnostic imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies; D012307:Risk Factors; D013961:Thyroid Gland / Q000378:metabolism / Q000473:pathology; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000556:secondary; D014055:Tomography, Emission-Computed
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18