Diagnostic performance of 18F-FDG-PET/CT in DTC patients with thyroglobulin elevation and negative iodine scintigraphy: a meta-analysis

Abstract

Purpose To evaluate the accuracy of 18F-FDG-PET/CT for the detection of recurrent and/or metastatic diseases in differentiated thyroid cancer (DTC) patients with thyroglobulin elevation and negative iodine scintigraphy. Whether PET/CT with TSH stimulation (sPET/CT) had better diagnostic performance than PET/CT without TSH stimulation (nsPET/CT) in this scenario was also evaluated. Methods PubMed and Embase databases were searched for eligible studies from January 2001 to December 2018. Only studies with clearly stated reference standard (histopathology confirmation and/or clinical/imaging follow-up) were included. Publication bias was assessed by Deeks funnel plot. The pooled sensitivity, specificity, diagnostic odds ratio (DOR) and the area under the summary receiver-operating characteristics curve (AUC) for PET/CT was determined by random-effect analysis, respectively. sPET/CT and nsPET/CT were compared pairwise for all diagnostic estimate indexes using Z-test. Results We included 17 studies with 1195 patients in this meta-analysis. The pooled sensitivity, specificity, DOR and AUC for PET/CT on patient-based data were 0.86 (95% CI: 0.79–0.91), 0.84 (95% CI: 0.72–0.91), 31.00 (95% CI: 12.00–80.00) and 0.91 (95% CI: 0.88–0.93), respectively. There was high heterogeneity (I 2 = 80% for sensitivity, I 2 = 82% for specificity) and possible publication bias (P = 0.01). Z test did not detect statistically significant difference between sPET/CT and nsPET/CT for all the diagnostic estimate indexes (all P > 0.05). Conclusions On patient-based analysis, 18F-FDG-PET/CT has high diagnostic accuracy for the detection of recurrent and/or metastatic diseases in DTC patients with thyroglobulin elevation and negative iodine scintigraphy, but existing studies were limited by high heterogeneity and possible publication bias. The diagnostic performance of sPET/CT may be not superior to nsPET/CT.

Impact of 18F-FDG PET/CT on Clinical Management of Suspected Radio-Iodine Refractory Differentiated Thyroid Cancer (RAI-R-DTC)

“…18F-FDG PET/CT has become an important tool in the postoperative management of patients with DTC, in disease staging and the follow-up of high-risk patients. Its diagnostic accuracy is highest in the evaluation of patients with "thyroglobulin elevated but negative iodine scintigraphy Syndrome" (TENIS syndrome) and in the early identification of RAI-R-DTC [5,6]. Empiric RAIT was demonstrated ineffective in patients with RAI-R-DTC, whereas 18F-FDG PET/CT was shown to reduce the number of ineffective RAIT and to provide guidance for loco-regional therapy such as surgery or external-beam radiation therapy (EBRT) [7,8].…”

PET/CT in thyroid cancer — the importance of BRAF mutations

“…Apart from the aforementioned scenarios in which FDG PET/CT might have or not a role in clinical practice, what remains clear as main indication for this technique is the post-operative stage, during follow-up, mainly in case of patients with aggressive histologies so to have a starting reference point or in chase of high or increasing Tg levels (Tg > 10 ng/mL or doubling time of less than 1 year) with negative post-therapeutic I-131 whole-body scan [39]. A meta-analysis performed by Wan et al [40] evaluated 17 studies with 571 patients who had recurrent or metastatic DTC and I-131 negative whole-body scan and determined that FDG-PET/CT a pooled sensitivity and specificity of 93.5% and 83.9%, respectively, with an overall diagnostic accuracy of 90.9%. Moreover, studies have shown that the positivity rate of FDG-PET/CT increases as Tg level rises, though there is lack of consensus on what the precise threshold level of Tg should be since positive findings have also been reported in 10-20% of DTC patients with Tg levels < 10 ng/mL [41].…”

Prognostic Value of Hybrid PET/MR Imaging in Patients with Differentiated Thyroid Cancer

“…It is conceivable that an optimal diagnostic strategy may be crucial to drive tailored therapeutic approaches. One of the most important diagnostic approaches available in the path of DTC patients is 18 F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) [ 6 , 7 , 8 , 9 , 10 ]. The American Thyroid Association (ATA) guidelines [ 4 ] recommend 18 F-FDG PET/CT in high-risk patients with measurable thyroglobulin (Tg) and an absence of 131 I uptake in the whole-body scan (WBS) for both the prognostics and diagnostics of metastatic patients for better management of patients with advanced disease and to evaluate the response to therapy.…”