title: Short-term Follow-up US Leads to Higher False-positive Results Without Detection of Structural Recurrences in PTMC.
abstract: To investigate the value of the annual follow-up neck ultrasonography (US) for postoperative surveillance in patients with papillary thyroid microcarcinoma (PTMC). This retrospective study has been approved by our institutional review board (IRB) with waiver for informed consent. A total of 375 patients diagnosed as PTMCs, who underwent total thyroidectomy with radioiodine remnant ablation were included, to identify the recurrence rate and the false-positive rate of annual ultrasound. The number, interval, and the results of follow-up US or fine needle aspiration were obtained from electronic medical records. Four (1.1%, 4/375) recurrences were found 3 years after the initial treatment, and only 1 patient (0.3%, 1/375) had a metastatic lymph node larger than 8 mm in the shortest diameter on US found 7.6 years after initial treatment with biochemical abnormalities. Cumulative risk of having at least 1 false-positive exam was 8.3% by the 8th US, and 8.1% by the 8-9 year follow-up. Cox multivariate regression showed shorter interval of follow-up US and presence of lymph node metastasis at initial surgery are independent predictors affecting the cumulative false-positive results (hazard ratio [HR], 0.60; 95% confidence interval [CI]: 0.49-0.73; P < 0.001 and HR, 2.19; 95% CI: 1.01-4.75; P = 0.048, respectively). Short-term follow-up US can result in higher cumulative false-positive results without detection of meaningful recurrences in patients with PTMCs who do not have biochemical abnormalities.
authors.affiliation: From the Department of Radiology, Severance Hospital, Research Institute of Radiological Science (JHY, E-KK, HJM, JYK); Department of Research Affairs, Biostatistics Collaboration Unit (HSL); Department of Radiology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (JHY); and Department of Radiology, Ajou University School of Medicine, Suwon, Korea (HGK).
authors.forename: Jung Hyun
authors.initials: JH
authors.lastname: Yoon
authors.forename: Hye Sun
authors.initials: HS
authors.lastname: Lee
authors.forename: Eun-Kyung
authors.initials: EK
authors.lastname: Kim
authors.forename: Ji Hyun
authors.initials: JH
authors.lastname: Youk
authors.forename: Hyun Gi
authors.initials: HG
authors.lastname: Kim
authors.forename: Hee Jung
authors.initials: HJ
authors.lastname: Moon
authors.forename: Jin Young
authors.initials: JY
authors.lastname: Kwak
mesh_terms: D055011:Ablation Techniques / Q000379:methods; D000328:Adult; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D013964:Thyroid Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D013965:Thyroidectomy / Q000379:methods; D013997:Time Factors; D014463:Ultrasonography
chemical_list: D007457:Iodine Radioisotopes