Value of serum thyroglobulin measurement in patients operated on for well differentiated thyroid carcinoma

OBJECTIVE: To study the clinical relevance of measurements of serum thyroglobulin in patients undergoing total thyroidectomy for well differentiated thyroid cancer. DESIGN: Prospective study. SETTING: University hospital, Sweden. SUBJECTS: 194 patients operated on for well differentiated thyroid cancer from 1 January 1978 to 31 December 1992. INTERVENTIONS: All patients underwent total thyroidectomy by a standard technique, and were prospectively followed up at regular intervals by clinical examination and measurement of the serum thyroglobulin concentration. RESULTS: Six patients whose thyroglobulin concentrations after operation were low or undetectable had gradual increases leading to detection of recurrences that could be treated successfully. Six patients had gradual increases without detectable recurrences. In 12 patients thyroglobulin concentrations remained high after operation with no signs of thyroid tissue remaining, which we interpreted as persistence of the disease. No recurrence was found without an appreciable rise in the thyroglobulin concentration. Thyroglobulin antibodies were found in 81 (42%). CONCLUSION: Measurement of the serum thyroglobulin concentration is a valuable addition to the follow up of patients operated on for highly differentiated thyroid cancer. In many cases it is the first sign of recurrent disease, thereby facilitating early and successful treatment.