Autoimmunity and thyrotropin level in developing thyroid malignancy

Malignancies and autoimmune thyroid disease are still controversial, but recent studies prove that a long lasting thyroid disease may be linked with malignancy, e.g. papillary thyroid carcinoma in patients with Hashimoto thyroiditis. Having in mind that thyrotropin is a thyroid growth factor, the relationship between its serum values, as well as the levels of anti-peroxidase and anti-thyroglobulin antibodies and thyroid malignancy in patients with nodular thyroid goiter was examined.

Six-hundred-thirty-seven medical records, which included the thyroid fine-needle aspiration cytology were retrospectively evaluated. Patients were grouped regarding the levels of thyrotropin, anti-peroxidase and anti-thyroglobulin antibodies (in or out of the reference ranges) and compared with cytology findings for establishing their prognostic potential for malignancy.

Elevated serum thyrotropin (≥ 4.5 mIU/L) was found in 27.3% of patients with thyroid malignancy compared with 10.8% with benign and 16.1% with unspecified cytology finding (p < 0.01). In the group of patients with malignant cytology findings 7.0% of them had elevated anti-peroxidase antibodies level, and 1.4% had anti-peroxidase antibodies level in reference range. In the group of patients with malignant cytology findings 4.2% of them had elevated anti-thyroglobulin antibodies level, and 1.4% had anti-thyroglobulin antibodies level in reference range.

In patients with elevated serum thyrotropin concentration and/or chronic thyroiditis the occurrence of thyroid malignancy is increased.