Long-Term Follow Up of Serum Thyroglobin Levels and its Clinical Implications in Subjects after Surgical Removal of “Cold” Thyroid Nodule

Summary

Increased thyroglobulin (Tg) serum level in females (n = 49) suffering from scintigraphically “cold“ thyroid nodule (395 ± 168, μg/1, x¯±SD) is significantly higher (p<0.001) in comparison with the data obtained from euthyroid healthy persons (28 ± 10, n= 15) or those diagnosed with scintigraphically functional thyroid nodule (72 ± 14, n = 15). No correlation between Tg and TSH serum levels has been seen before surgical removal of “cold” nodule (r_xy= +0.34).

In 49 out of 75 cases (65.3 % ) struma colloids were confirmed pathohistologically. After surgery, “cold” thyroid nodule was removed, serum Tg level decreased progressively within several days and three months afterwards, Tg level in most patients was mainly within the normal range for a healthy subject. The positive correlation between Tg and TSH was established three months after surgical removal of the nodule (r_xy=+0.90). An elevation of serum Tg level was found in 16 out of the 49 patients during different postoperative periods (from 2 to 9 years). Under thyroxine treatment, in most of these patients a significant decrease of serum Tg level was observed. However, in a few treated patients, no change in Tg level was seen. Further clinical control in thyroxine-nonsuppressive patients discovered a compensatory hypertrophy of thyroid tissue and the appearance of a new thyroid nodule later. Present data and clinical experience suggest that long-term follow-up of serum Tg level in patients after surgical removal of “cold” thyroid nodule, brings about to early diagnosis of thyroid tissue postoperative hypertrophy before the appearance of thyroid gland nodule relapse.

Key words

“Cold” thyroid nodule - Thyroglobulin follow up