Thyroglobulin monitoring after treatment of well-differentiated thyroid cancer

Aims. The prognosis for well-differentiated thyroid carcinomas is favourable after treatment, but the rate of recurrence is around 20%. Cervical ultrasonography, radio-iodine scans, and monitoring of serum thyroglobulin (T-g) levels allow these recurrences to be diagnosed. The management of patients with isolated elevated T-g levels is controversial in the presence of negative radio-iodine scans. Methods. The records of 57 patients diagnosed with recurrence of well-differentiated thyroid cancer were reviewed. Serum T-g was not evaluated in 31 of these patients (group 1) and measured in the other 26 cases (group 2). Results. Forty-three recurrence sites were found; four deposits in the thyroid bed and 39 cervical metastatic nodes, with an average of five nodes per patient. The radioiodine scan was accurate in detecting 10/24 of cases, radiology in 9/17, and elevated T-g levels in 20/25. Thirteen patients with recurrences diagnosed on the basis of T-g levels had negative radio-iodine scans. After surgery, T-g levels were normal in 10 patients from group 1 and 16 patients from group 2 (p = 0.0078). Conclusions. Elevated T-g levels are indicative of disease progression or recurrence in patients who have previously been operated on for well-differentiated thyroid cancer. Even when the radiological study or radio-iodine scan is normal, surgical re-exploration of the neck, with total thyroidectonny and lymphadenectomy, is advisable. (C) 2004 Elsevier Ltd. All rights reserved.