Risk factors for hypothyroidism and thyroid hormone replacement after hemithyroidectomy in papillary thyroid carcinoma

Abstract

Thyroid lobectomy is now preferred over total thyroidectomy to preserve thyroid function and reduce complications in patients with low-risk papillary thyroid carcinoma (PTC). One inevitable consequence of thyroidectomy includes hypothyroidism. This study aimed to evaluate the risk factors for hypothyroidism and thyroid hormone replacement after hemithyroidectomy in patients with PTC. We retrospectively studied 353 patients with PTC who underwent hemithyroidectomy with or without central neck dissection from January 2012 to January 2019. We excluded patients who had hypo- or hyperthyroidism preoperatively and those who underwent total or subtotal thyroidectomy. We analyzed various risk factors related to postoperative hypothyroidism and thyroid hormone supplementation. Of the patients, 54.7% showed hypothyroidism after hemithyroidectomy (n=193 with n=157, subclinical hypothyroidism; n=36, overt hypothyroidism). Ninety-one percent of postoperative hypothyroidism cases developed within 7 months postoperatively. Eventually, 43.1% (n=152) of patients received levothyroxine after hemithyroidectomy. Preoperative high thyroid-stimulating hormone (TSH) level and low free thyroxine (fT4) level were significantly associated with postoperative hypothyroidism and the need for thyroid hormone supplementation postoperatively. Preoperative TSH and fT4 levels are predictive risk factors of hypothyroidism and need for supplementation of levothyroxine after hemithyroidectomy in patients with PTC. Finally, approximately 43% of patients need levothyroxine supplementation after hemithyroidectomy, and individual preoperative counseling is necessary for these patients.