Complementary role of whole body scan and serum thyroglobulin determination in the follow-up of differentiated thyroid carcinoma.

In 233 patients with differentiated thyroid carcinoma previously treated by total thyroidectomy supplemented, when necessary, with a therapeutic dose of 131I, serum thyroglobulin determinations and whole body scans were simultaneously performed. 82 of the 233 showed local or distant metastases: they were detected by both tests only in 36 cases. In 43 patients thyroglobulin was positive but without pathological concentrations of 131I at whole body scan were observed. The remaining 3 cases were detected on the basis of the positive whole body scan only, without increase in the circulating thyroglobulin. These results suggest that caution should be taken when considering thyroglobulin determination as possible substitutive test of whole body scan in the follow-up of differentiated thyroid carcinoma. However, for optimal sensitivity and reliability the complementary role of the two tests is stressed.