Endpoints
Local recurrence was defined as at least carcinoma in situ of the
laryngeal mucosa on the ipsilateral or contralateral laryngeal side
after complete removal of tumor with microscopically and histologically
negative margins at the initial surgery. The 5-year overall survival
(OS) was defined as the interval between surgery and the date of the
last consultation or death. The 5-year disease-free survival (DFS) rate
was defined as the percentage of patients who were alive and cancer-free
at 5 years after the date of the initial surgery.