Oncologic outcomes of robotic thyroidectomy: 5-year experience with propensity score matching

The oncologic outcome of robotic thyroidectomy is not yet well established. The aim of this study was to evaluate the recurrence rate after robotic thyroidectomy in comparison with conventional thyroidectomy for papillary thyroid carcinoma (PTC). We analyzed 896 patients with PTC who either underwent robotic (212 patients using a gasless unilateral axillary or an axillo-breast approach) or conventional cervical thyroidectomy (684 patients) with/without central neck dissection between October 2008 and February 2014. We excluded patients who underwent concomitant lateral neck dissection or completion thyroidectomy, and cases with T4 tumor, tumor lager than 4 cm, other types of thyroid cancer, recurrent cancer, and distant metastasis. A propensity score matching analysis was done with ten covariates including age, gender, body mass index, tumor size, multifocality, bilaterality, extrathyroidal extension, type of thyroidectomy, extent of central neck dissection, and RAI ablation to reduce selection bias. In baseline data, the male ratio and the mean age were lower in the robotic group. Stage, multifocality, and bilaterality were higher in the conventional group. The rate of total thyroidectomy was higher in the conventional group. The two matched groups of each 185 patients were produced and well balanced by propensity score matching. In the comparison of propensity score matched groups, operative time was longer in the robotic group (P < 0.001), and postoperative complications did not differ between the two groups, except for transient hypoparathyroidism and formation of seroma. The recurrence rate did not differ between the two groups after a mean follow-up of 43.6 months (0.5 and 1.1 % in the robotic and conventional groups, respectively, P = 0.375). The oncologic outcome of robotic thyroidectomy in 5-year experience is comparable to that of conventional thyroidectomy in selected patients with PTC.