[Clinical significance of three-week thyroglobulin test in patients with thyroid cancer undergoing thyroidectomy].

High level of thyroglobulin (Tg) after thyroidectomy has been shown to be an early marker of either metastases or local recurrence of differentiated thyroid cancer (DTC). The aim of this study was to evaluate the relation between Tg level estimated on the third week after thyroidectomy and clinic-pathologic characteristics of DTC as a possible prognostic criterion used to mark the patients with radioiodine therapy indications. Research data on 45 patients (39 women, 6 men, age 22-75 years) with DTC and without high level of Tg autoantibodies have been included in the study. Eleven patients underwent surgical treatment due to disease recurrence. In all patients Tg and thyroid hormones levels were measured before the thyroidectomy and on the third week after it. The postoperative level of Tg as TTM coefficient (ratio of postoperative Tg to daily L-thyroxin dose in mcg to body weight in kg) was higher in patients with unfavorable prognosis: (a) capsular invasion, (b) cervical lymph nodes metastases, (c) advanced disease stage, (d) high risk of recurrence. The postoperative serum Tg levels were similar in primary disease patients and patients with DTC recurrence. There was no relation between preoperative Tg level and any prognostic factors although there was a tendency to higher (more than 2 ng/ml) Tg levels in patents with high preoperative Tg levels. Finally, the serum Tg level on the third week after thyroidectomy is a valuable prognostic criterion and can be used in DTC to determine the radioiodine therapy indications.