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

PURPOSE: To evaluate the accuracy of 18F-FDG-PET/CT for 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 was 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 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 was compared pair-wisely 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 (I2=80% for sensitivity, I2=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, 18-FDG-PET/CT has high diagnostic accuracy for 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.