Prognostic implication of fluorine‐18 fluorodeoxyglucose positron emission tomography/computed tomography in patients with recurrent papillary thyroid cancer

• Published in: Head & neck 2018-01, Vol.40 (1), p.94-102
• Main Authors: Kang, Ji‐Hun, Jung, Da‐Woon, Pak, Kyoung‐June, Kim, In‐Ju, Kim, Hak‐Jin, Cho, Jae‐Keun, Shin, Sung‐Chan, Wang, Soo‐Geun, Lee, Byung‐Joo
• Format: Article
• Language: English
• Subjects: Adult; Aged; Carcinoma, Papillary - diagnostic imaging; Carcinoma, Papillary - mortality; Carcinoma, Papillary - surgery; Cohort Studies; Computed tomography; Disease-Free Survival; Female; Fluorodeoxyglucose F18; Head and neck; Humans; Kaplan-Meier Estimate; Male; maximum standardized uptake value (SUVmax); Medical prognosis; Middle Aged; Neck; Neck Dissection; Neoplasm Recurrence, Local - diagnostic imaging; Neoplasm Recurrence, Local - mortality; Neoplasm Recurrence, Local - surgery; Papillary thyroid cancer; Patients; Positron emission tomography; positron emission tomography (PET)/CT; Positron Emission Tomography Computed Tomography - methods; Predictive Value of Tests; Prognosis; recurrent thyroid cancer; Retrospective Studies; Risk Assessment; Scintigraphy; serum thyroglobulin (Tg); Survival; Survival Analysis; Thyroglobulin; thyroglobulin antibody (TgAb); Thyroid cancer; Thyroid Cancer, Papillary; Thyroid Neoplasms - diagnostic imaging; Thyroid Neoplasms - mortality; Thyroid Neoplasms - surgery; Thyroidectomy - methods; Tomography; Tomography, X-Ray Computed - methods
• ISSN: 1043-3074; 1097-0347
• DOI: 10.1002/hed.24967

Background Fluorine‐18 fluorodeoxyglucose positron emission tomography/CT (18F‐FDG PET/CT) has been widely accepted as an effective method for detecting recurrent papillary thyroid cancer (PTC) in patients with increased serum thyroglobulin (Tg) or Tg antibody (TgAb) levels and negative whole‐body scintigraphy (WBS) results. The role of WBS as a diagnostic tool in detecting recurrence has relatively decreased recently. However, only a few studies have examined the usefulness of 18F‐FDG PET/CT for evaluating patients with recurrent PTC, regardless of the WBS results. The purpose of this analysis was to evaluate the diagnostic value and prognostic role of 18F‐FDG PET/CT for patients with recurrent PTC, irrespective of their WBS results. Methods Sixty‐six patients with locoregional recurrent PTC who underwent 18F‐FDG PET/CT and neck CT within 6 months before surgical treatment were included in this retrospective analysis. Imaging findings were compared with postoperative histopathologic results. The diagnostic values of 18F‐FDG PET/CT and neck CT were compared according to the serum Tg and TgAb levels and cervical levels. Each patient's status at the last follow‐up was also reviewed, and survival probabilities were estimated using the Kaplan‐Meier plot. Results The sensitivity, specificity, and diagnostic accuracy of 18F‐FDG PET/CT for the entire patient group were 38.5%, 90.2%, and 58.3%, respectively. The corresponding neck CT values were 55.0%, 85.7%, and 66.7%, respectively. According to the serum Tg and TgAb levels, except for the specificity, most diagnostic values of 18F‐FDG PET/CT were worse than those of the neck CTs, with or without statistical significance. For the high maximum standardized uptake value (SUVmax) group (SUVmax >10) and the low SUVmax group, the median locoregional disease‐free survival times were 33.3 months and 81.8 months, respectively (P < .001). Conclusion The diagnostic value of 18F‐FDG PET/CT for localizing recurrent lesions was worse than that of the neck CT, irrespective of the WBS results. However, patients with a higher SUVmax showed a significantly worse prognosis than did those with a lower SUVmax. Therefore, we suggest that, in patients with recurrent PTC, 18F‐FDG PET/CT should be considered for prognostication rather than diagnosis.