Changes of Thyroid Function in Patients Undergoing Partial Thyroidectomy for Benign Thyroid Tumors / 대한내분비외과학회지

ABSTRACT

PURPOSE: Lobectomy or subtotal thyroidectomy in patients with a benign thyroid tumor or goiter can give rise to hypothyroidism due to the reduced volume of the hormone-secreting thyroid gland. This study investigated the incidence of hypothyroidism in such patients and the clinical risk factors. METHODS: One hundred seven patients who underwent partial thyroidectomy for benign thyroid tumor or goiter from January 2003 to February 2005 in our institution were reviewed retrospectively. Patients who had been preoperatively diagnosed with hyper- or hypothyroidism preoperatively were excluded. Postoperative hypothyroidism was defined as an elevated serum thyroid stimulating hormone (TSH) level >6.5 µIU/L at about 6 months postthyroidectomy. RESULTS: The mean age of the 107 patients was 42.2 years. Ninety patients (84.1%) were female. Subtotal thyroidectomy was performed in 20 patients, lobectomy in 83 patients and enucleation in four patients. The most common pathologic diagnosis was nodular hyperplasia (86.0%). Postoperative hypothyroidism developed after surgery in 19 (21.8%) patients. Patients were evaluated for age, gender, preoperative TSH level, tumor size, tumor number, extent of the resection, thickness of thyroid isthmus and the presence of pathologic thyroiditis or thyroid autoantibody. Advanced age, elevated preoperative TSH level and extensive resection of the thyroid gland were significantly associated with postoperative hypothyroidism. CONCLUSION: Since many patients with a benign thyroid nodule can maintain a normal thyroid function even after thyroidectomy, preservation of more thyroid tissue during the operation is desirable, especially in young patients with a low-normal TSH level, unless the possibility of disease recurrence is high.