Hypothyroidism, new nodule formation and increase in nodule size in patients who have undergone hemithyroidectomy

INTRODUCTION The current medical literature has conflicting results about factors related to hypothyroidism and nodular recurrences during follow-up of hemithyroidectomized patients. We aimed to evaluate factors that may have a role in new nodule formation, hypothyroidism, increase in thyroid lobe and increase in nodule volumes in these patients with and without Hashimoto's thyroiditis (HT), and with and without levothyroxine (LT4) use. MATERIAL AND METHODS We enrolled 140 patients from five different hospitals in Ankara and evaluated their thyroid tests, autoantibody titre results and ultrasonographic findings longitudinally between two visits with a minimum 6-month interval. RESULTS In patients with HT there was no significant difference between the two visits but in patients without HT, thyroid stimulating hormone (TSH) levels and nodule volume were higher, and free T4 levels were lower in the second visit. Similarly, in patients with LT4 treatment there was no difference in TSH, free T4 levels, or lobe or nodule size between the two visits, but the patients without LT4 had free T4 levels lower in the second visit. Regression analysis revealed a relationship between first visit TSH levels and hypothyroidism during follow-up. CONCLUSIONS Patients who have undergone hemithyroidectomy without LT4 treatment and without HT diagnosis should be followed up more carefully for thyroid tests, new nodule formation and increase in nodule size. The TSH levels at the beginning of the follow-up may be helpful to estimate hypothyroidism in hemithyroidectomized patients.