The role of TSH for 18F-FDG-PET in the diagnosis of recurrence and metastases of differentiated thyroid carcinoma with elevated thyroglobulin and negative scan: a meta-analysis

Abstract

To establish the effects of TSH stimulation on the uptake of fluorine-18-labeled 2-fluoro-2-deoxy-d-glucose for differentiated thyroid carcinoma (DTC) with thyroglobulin-positive and scan negative metastases. We searched the MEDLINE, EMBASE and the Cochrane Library for prospective controlled trials using TSH stimulation as an intervention. The outcomes of positron emission tomography (PET)-positive lesions, tumor-to-background ratio, maximum standard uptake value of the detected lesions were extracted and synthesized, and patients with the altered clinical management were studied. A meta-analysis was carried out using the Review Manager software. Seven prospective controlled clinical trials with 168 patients were found. All studies had a low risk of bias. PET scans under TSH stimulation versus thyroid hormone suppression showed statistically significant differences in the number of patients with PET true-positive lesions (odds ratio (OR) 2.45, 95% confidence interval (CI) 1.23-4.90) and in the number of the PET-detected lesions (OR 4.92, 95% CI 2.70-8.95) and tumor-to-background ratios. PET scans taken under TSH stimulation altered clinical management in altogether 12/130 (9%) patients in five paired studies (OR 2.40, 95% CI 1.11-5.22). The data indicate that TSH stimulation should be recommended for DTC patients undergoing PET scanning in these circumstances. However, further well-designed studies emphasizing on the clinical significance of altered management by PET under TSH stimulation are needed.