Long-term effects of thyroid fine-needle biopsy on the thyroid-related biochemical parameters

Thyroid fine-needle biopsy (FNB) is a simple, reliable, inexpensive and generally safe diagnostic procedure in the management of thyroid nodules. FNB may trigger biochemical alterations through destruction of thyroid follicles. We aimed to investigate long-term post-FNB alterations in serum thyroid-related parameters.

One hundred and ten consecutive patients with thyroid nodular disease were subjected to FNB. Thyroid stimulating hormone (TSH), free thyroxine (FT4) and free triiodothyronine (FT3), thyroglobulin (Tg), thyroglobulin autoantibodies (anti-Tg), thyroid-peroxidase autoantibodies (anti-TPO) were measured in all subjects at baseline, 10 days, 2 and 6 months. Subsequently, patients were divided into subgroups according to the technique of FNB, the presence of disease characteristics as thyroid autoimmunity (Hashimoto's thyroiditis), goitre, singularity-maximum diameter-blood pattern of the nodule(-s), the number of passes and the administration of L-thyroxine (LT4).

A significant increase in Tg, anti-Tg and FT3 levels was observed. These alterations were more prominent within patients with dominant nodule's maximum diameter ≥ 2 cm or without Hashimoto's thyroiditis. Tg and anti-Tg levels were significantly increased only in patients not being on LT4. On the other hand, FNB technique did not affect any of the measured parameters.

Our data suggest that FNB results in statistically significant but clinically insignificant increases in Tg, anti-Tg and FT3 levels, implying a thyroid trauma of some level, more likely to happen in patients with larger nodules. The FNB technique used has no effect on the thyroid-related biochemical parameters.