Relationship Between Thyroid-Stimulating Hormone Level and Aggressive Pathological Features of Papillary Thyroid Cancer

Objectives: Thyroid-stimulating hormones (TSHs) are associated with the risk of differentiated thyroid cancer. The relationship between pre-operative TSH levels and aggressive features is unclear. We aimed to evaluate the relationship between pathological features of papillary thyroid carcinoma (PTC) and high TSH levels. Methods: Patients who were operated between 2012 and 2017 and who were found to have PTC in their pathology were included in the study. The relationship between TSH and the features of tumor aggressiveness was evaluated in the patients. Results:Of the 132 patients, TSH level was significantly higher in those with lymphovascular invasion than those without (p=0.048), in those with central metastases than in those without (p=0.014), and in those with extrathyroidal spread than in those without (p=0.003). When patients were categorized into four 25% quartiles according to TSH (mUI/mL) level; the rate of extrathyroidal invasion increased as the TSH level increased, and the level was significantly higher in quartile 1 than the others, with significant difference (p=0.030). Conclusion: Pre-operative increase in TSH level is associated with an increased risk of extrathyroidal spread and central lymph node metastasis. TSH level may be a pre-operative valuable predictive factor for patients' risk of central metastasis.