Endocrine Abstracts

Objective: Role of thyroid stimulating hormone (TSH) in thyroid oncogenesis is not clear. There are few trials about relationship of TSH, thyroid hormones and autoantibodies with malignancy. We aimed to investigate thyroid function tests and malignancy in patients evaluated in thyroid disease council and decided to be managed with thyroidectomy.

Method: About 272 patients were included in the study. Hyperthyroid and hypothyroid patients, patients on L-thyroxine and antithyroid treatment and those with previous thyroidectomy were excluded. Thyroid function tests (TSH, free T3, free T4, anti-TPO, anti-TG) were recorded before thyroidectomy. Patients were grouped in 2 according to histopathologic results, benign and malignant; and grouped in 3 according to TSH levels, group 1:TSH<0.9 μIU/ml, group 2: TSH: 0.9–1.49 μIU/ml, group 3: TSH≥1.5 μIU/ml.

Results: There were 224 female and 48 male patients and mean age was 44.4±11.7 (18–75). Histopathologically, there were 174 benign and 98 malign reports.

TSH levels and malignancy was found to be correlated significiantly (P<0.001). Although there was no difference between group 1 and 2, difference between 2 and 3 was significant (P<0.001, OR:2.87). Malignancy was higher in patients with TSH≥1.5 μIU/ml. Median free T3 was 3.55 pg/ml (1.4–5.24) in patients with benign pathology whereas it was 3.35 pg/ml (1.8–4.79) in patients with malign pathology. There was statistically significant difference (P=0.006, OR:0.61). Anti-TPO was positive in 17.7% of benign group and 31.1 in malign group. Again, these results were statistically significant (P=0.014, OR:2.10). Antithyroglobulin was positive in 19.9% and 32.2% of benign and malign patients, respectively (P=0.028, OR:1.92). Multiple regression analysis also showed TSH and free T3 effect on malignancy.

Conclusion: Our results showed that, in euthyroid patients, presence of autoantibody, low free T3 even in normal ranges and TSH levels above 1.5 μIU/ml are all related to malignancy