Thyroglobulin value in patients surgically treated for differentiated thyroid carcinoma

Introduction. Thyroglobulin is composed glycoprotein, and it is synthesized by follicular cells of the thyroid gland. Treatment of differentiated thyroid carcinomas involves total thyroidectomy followed by radioiodine ablation of a potential remaining tissue. The measurement of thyroglobulin in the postoperative follow-up can serve as an indicator of tumor growth or recurrence of the disease. Objective. The aim of this paper is to examine the value of thyroglobulin in patients surgically treated for differentiated thyroid cancer who had metastases in the lymph nodes of the neck, as well as in operated on patients without any evident metastasis. Methods. Thyroglobulin values in the serum of 58 patients were analyzed. Two groups were formed. The thyroglobulin value was established with the use of IRMA-hTg (125I) system. Normal levels of thyroglobulin were from 2 ng/ml to 65 ng/ml. For all of 58 patients, thyroglobulin was determined three times. The first, so-called pre-ablation thyroglobulin was determined immediately before the application of 131I ablation dose. The second and the third measurements were conducted six to eight months and one year, respectively, after the application of the ablation dose respectively. Results. The first group consisted of 14 patients with histologically proven metastases in the lymph nodes of the neck, while the second group consisted of 44 patients without any evident metastases. The average thyroglobulin value of pre-ablation in the patients from the first group was 43.45 ng/ml, while in the second was 7.57 ng/ml. Levene’s test (with p = 0.00, i.e p < 0.05), demonstrated a statistically significant difference. Furthermore, in both groups, there was statistically significant difference between pre-ablation and post-ablation thyroglobulin values (Student’s t-test with p < 0.05). Conclusion It can be concluded that the average value of thyroglobulin was significantly higher in patients with lymph node metastases in the neck. We are of the opinion that the determination of thyroglobulin, despite individual variations, may serve as a good indicator to assist in monitoring of patients surgically treated for differentiated thyroid cancer