Elevated serum thyroglobulin. A marker of metastases in differentiated thyroid carcinomas.

Abstract

A B S T R A C T The presence of human thyroglobulin (HTg) in serum of patients with differentiated thyroid carcinoma was studied. The thyroglobulin detected in the serum of such patients was identical by immunological criteria to the serum standard used in the radioimmunoassay. The serum thyroglobulin levels in untreated patients with differentiated thyroid carcinoma ranged from 22.0 to 445.0 ng/ml with a mean of 144.3± 46.5 ng/ml (SEM) (n = 10). The mean serum thyroglobulin measured postoperatively in seven of these patients was 6.4±+1.5 ng/ml, not statistically different from the mean level of 5.1±0.49 ng/ml (range 0-20.7 ng/ml) observed in 71 out of 95 control subjects with detectable HTg levels. By contrast serum HTg levels were normal or undetectable in subjects with medullary carcinoma of the thyroid. HTg levels were within normal limits in sera of patients who had previously undergone successful therapy for a differentiated thyroid carcinoma and in whom no metastases could be documented. The mean level for this group was 4.9±0.51 ng/ml (n = 43). In contrast, patients with documented metastases had a mean serum thyroglobulin level of 464.9±155.6 ng/ml (n = 6). The data support the thesis that in differentiated thyroid carcinoma serum thyroglobulin levels are elevated when metastases develop after initial treatment. It is proposed that the measurement of thyroglobulin in the serum represents a simple and valuable adjunct in the posttreatment follow-up of patients with differentiated thyroid cancer.

The Action of Thyroid Hormone

“…Its concentration in serum rises with thyroid gland hypersecretion and particularly with thyroid gland damage as after surgery or in subacute thyroidities. The level of serum TG may be very high in some cases of metastatic thyroid carcinoma (Van Herle et al, 1973;Van Herle & Uller, 1975).…”

Serum thyroglobulin (Tg) concentration in healthy subjects: Absence of age- and sex-related differences.

“…Several previous studies (Van Herle et al, 1973 ;Izumi and Larsen, 1978 ;Gardner et al, 1979;Pacini et al, 1980) have demonstrated varying degrees of elevated levels of serum Tg in thyroid diseases such as Graves' disease and subacute thyroiditis. In patients with thyroid carcinoma, Tg is a useful marker for their follow-up (Van Herle and Uller, 1975 ;Pacini et al, 1980), since the levels of serum Tg after thyroidectomy are low or undetectable in patients with complete remission, whereas elevated serum Tg indicates metastasis and/or recurrence of carcinoma.…”

Measuring Serum Thyroglobulin in Patients with Follicular Thyroid Nodule: Its Diagnostic Implications.

“…Some of them examined factors which affect the level of serum Tg [14][15][16][17], and others investigated the diagnostic value of the test in the management of thyroid nodules [18][19][20][21][22]. Experts reported that the measurement of serum Tg is of no value in the differential diagnosis of thyroid tumor [8][9][10], but we should be critical of their findings in two respects; an analysis and a study population.…”