Department of Urology;
Chung-Ang University Hospital;
Chung-Ang University College of Medicine;
Dongjak-gu;
Seoul 06973;
Korea;
Department of Urology;
Asan Medical Center;
University of Ulsan College of Medicine;
Songpa-gu;
Seoul 05505;
Korea;
biochemical recurrence; frozen section; positive surgical margin; robotic-assisted prostatectomy;