2 MATERIAL S A ND METHODS
We retrospectively reviewed data from 63 patients with OPSCC who underwent primary TORS with or without adjuvant radiation or chemoradiation therapy between January 2010 and December 2018. Of 63 patients, we excluded 22 patients from the study, including those who did not perform a swallowing and speech test between two and three years after TORS (16 patients) and who had a previous history of head and neck surgery or irradiation (1 patient), or who had cancer recurrence within two to three years after TORS before functional evaluation (5 patients). Finally, the remaining 41 patients were included, and data from these patients were analyzed in this study. The study protocol was approved by the institutional review board.
All operations were performed by a single surgeon. We performed adjuvant radiation therapy after TORS in patients with close surgical margin or lymph node metastasis and adjuvant concurrent chemoradiation therapy in patients with positive margin or extranodal extension.
Evaluation of postoperative functional speech and swallowing outcomes was performed by the mobility of the tongue, maximal phonation time, articulation, verbal diadochokinesis, reading speed, and modified barium swallowing tests conducted between two and three years after surgery Tracheostomy tube or percutaneous endoscopic gastrostomy (PEG) tube dependency was also investigated.