Does Tumor Size Affect Surgical Outcomes of Transoral Robotic Thyroidectomy for Patients with Papillary Thyroid Carcinoma? A Retrospective Cohort Study

Background: Transoral robotic thyroidectomy (TORT) for differentiated thyroid carcinoma is increasing in popularity. However, studies are limited to small tumors. This study aimed to compare the outcomes of TORT for papillary thyroid carcinomas smaller than 1 cm and 1 cm or larger. Methods: The study analyzed 269 patients with papillary thyroid carcinoma who underwent TORT at Korea University Hospital, Korea between January 2001 and December 2017. Surgical outcomes and postoperative complications were compared. Results: Group 1 (tumor < 1 cm) had 215 patients, and group 2 (tumor ≥ 1 cm) had 54 patients. The majority of the patients underwent lobectomy (95.8% in group 1 and 87.0% in group 2; p = 0.339) and unilateral central neck dissection (96.3% in group 1 and 88.9% in group 2; p = 0.024). The two groups did not differ significantly in terms of gender, age, body mass index, thyroiditis status, Da Vinci model. or operative procedure. The majority of the tumors in group 1 (73%) had T1a staging, whereas the majority of the tumors in group 2 were stage T1b or T3a (44.4% in each group; p = 0.000). Most of the patients in group 1 had N0 staging (59.1%), whereas most of the patients in group 2 had N1a staging (55.6%; p = 0.026). The mean operative time was significantly longer in group 2 (198.0 ± 34.2 min in group 1 vs. 215.7 ± 49.3 min in group 2; p = 0.015). The two groups did not differ significantly regarding length of stay, postoperative pain score, or thyroglobulin level. No patients experienced locoregional or distant recurrence. No statistically significant difference in overall complications was observed (p = 0.214). Conclusions: Transoral robotic thyroidectomy is a safe and effective procedure and may be a feasible option for patients with papillary thyroid carcinomas larger than 1 cm.