Treatment strategy for intermediate-risk papillary thyroid cancer: Focus on postoperative hypothyroidism following lobectomy.

Objective: An optimal surgical approach for intermediate-risk papillary thyroid cancer (PTC) has not yet been established. The surgical procedure should be determined based on treatment outcomes and postoperative complications. This study aimed to evaluate appropriate surgical strategies for patients with intermediate-risk PTC by comparing treatment outcomes and postoperative complications following total thyroidectomy and lobectomy.

Methods: This retrospective analysis was conducted on 123 patients with intermediate-risk PTC treated in our department between January 2008 and December 2022. The risk of PTC was classified according to the 2024 Guidelines for the Clinical Treatment of Thyroid Nodules from the Japan Association of Endocrine Surgery.

Results: Of the 123 patients, 27 underwent total thyroidectomy, and 96 underwent lobectomy. No significant differences were observed between the two surgical groups in terms of survival or recurrence rates. None of the patients showed bilateral recurrent laryngeal nerve (RLN) palsy postoperatively. Postoperative unilateral RLN palsy occurrence differed significantly between the total thyroidectomy and lobectomy groups, with five cases in each (5.2 and 18.5 %, respectively; p = 0.04). Permanent hypoparathyroidism was observed in two patients (7.4 %) in the total thyroidectomy group. Postoperative hypothyroidism developed in 42 (43.8 %) lobectomy cases, with 32 requiring the administration of levothyroxine therapy. A significant association was observed between preoperative thyroid-stimulating hormone (TSH) levels (≥2.0 μIU/mL) and postoperative hypothyroidism (p < 0.001).

Conclusion: No significant difference in treatment outcomes was observed between patients with intermediate-risk PTC who underwent total thyroidectomy and those who underwent lobectomy. In cases with preoperative TSH levels ≥2.0 μIU/mL, total thyroidectomy may be a more suitable approach, given the increased likelihood of requiring postoperative levothyroxine administration following lobectomy.