TITLE: Impact of FDG PET on patients with differentiated thyroid cancer who present with elevated thyroglobulin and negative 131I scan.

REF:Schlutter et al. J Nucl Med. 2001 Jan;42(1):71-6 http://www.ncbi.nlm.nih.gov/entrez/...3&dopt=Abstract

STUDY TYPE: prospective trial

PATIENTS: pts with differentiated thyroid cancer, elevated thyroglobulin, and negative I-131 whole body scans

FINDINGS: The positive predictive value of FDG PET was 83% (34/41), whereas the negative predictive value was 25% (5/20). Treatment was directly changed in 19 of 34 (56%) patients with true-positive PET studies: 18 patients had further surgery, and 4 patients were referred for external irradiation, 3 of them after incomplete removal of local recurrences. FDG PET showed widespread disease in 7 patients; thus, palliative treatment, rather than curative therapy, was initiated.

CONCLUSION: FDG PET is useful in patients with differentiated thyroid cancer who present with increased thyroglobulin levels and negative I-131 scans because it permits selection of patients for surgery, which may be curative. FDG PET is most promising at hTg levels of >10 microg/L.