OBJECTIVE: Studies published in the last few years suggest that increased thyroid-stimulating hormone (TSH) values are associated with increased risk of thyroid cancer and/or a more advanced stage of malignancy. The aim of this study was to explore the hypothesis that TSH may be a risk factor for thyroid cancer initiation, which was tested by comparing TSH concentrations in patients with incidental micro papillary cancer (mPTC) and controls with a negative histologic exam.
METHODS: Patients were retrospectively selected from medical records from 3 district hospitals. Patients with biochemical/histologic evidence of autoimmunity, thyroid function-interfering drugs, and autonomously functioning areas, were excluded. TSH values of 41 patients with an incidental mPTC were then compared with a sex- and age-matched group of patients who had a negative histologic exam at a 4:1 ratio (164 patients).
RESULTS: TSH was not significantly different in the mPTC group compared to the controls (1.1 ± 0.7 vs. 1.3 ± 1.0 mIU/L). After adjustment for age and gender, TSH levels were still not found to be significantly different between groups. In the mPTC group, TSH levels were not found to be a significant predictor of tumor size after adjusting for age and gender (β = 0.035, SE = 0.73, P = .844).
CONCLUSIONS: On the basis of these results, the hypothesis that TSH is involved in de novo oncogenesis of PTC is not supported.