Measurement of serum thyroglobulin is of value in detecting tumour recurrence following treatment of differentiated thyroid carcinoma by lobectomy

Abstract

Abstract Serum thyroglobulin was measured in 243 samples from 84 patients (20 men and 64 women, with a mean age of 48·9(14) years) with differentiated thyroid carcinoma treated by lobectomy, and in 58 patients treated by total thyroidectomy. Both groups were given thyroxine to suppress thyroid stimulating hormone (TSH). Three patients in the lobectomy group and eight in the thyroidectomy group had evidence of tumour recurrence. Serum thyroglobulin concentration was elevated in the presence of known recurrent tumour (P < 0·001) irrespective of the type of operation, and in its absence tended to be higher in the lobectomy than in the thyroidectomy group (median 4 μg/l versus 2 μg/l, P < 0·05). Serum thyroglobulin levels of less than 10 μg/l could confirm the absence of otherwise known tumour recurrence in both groups with a specificity of 100 per cent, and sensitivities of 80 per cent and 86 per cent in the lobectomy and thyroidectomy groups respectively. Exclusion of samples liable to spurious elevation of thyroglobulin improved the sensitivity in the lobectomy group to 92 per cent. Despite the presence of residual thyroid tissue, measurement of serum thyroglobulin can exclude the presence of significant metastases in most patients following lobectomy for thyroid carcinoma.