title: Learning curve for robot-assisted laparoscopic radical prostatectomy for pathologic t2 disease.
abstract: OBJECTIVE
  To investigate the learning curve for robot-assisted laparoscopic radical prostatectomy (RALP) for pathologic T2 disease, we examined differences in perioperative outcomes according to time period.
  
  
  METHODS
  Between July 2005 and June 2008, a total of 307 consecutive patients underwent RALP for prostate cancer and 205 patients had pathologic T2 disease. Patients were grouped into 6-month time periods. We collected and examined the patient's perioperative data including age, body mass index (BMI), prostate-specific antigen (PSA), operation time, estimated blood loss, and positive surgical margin.
  
  
  RESULTS
  There were no significant differences among the groups in age (p=0.705), BMI (p=0.246), PSA (p=0.425), or prostate volume (p=0.380). Operation time (p<0.001) and estimated blood loss (p<0.001) decreased significantly with time. The positive surgical margin rate also showed a decreasing trend, but this was not significant (p=0.680).
  
  
  CONCLUSIONS
  Operation time and estimated blood loss had a steep learning curve during the early 24 cases and then stabilized. A positive surgical margin rate, however, did not have a significant learning curve, although the positive surgical margin decreased continuously.
authors.affiliation: Department of Urology, College of Medicine, Hanyang University, Seoul, Korea.
authors.forename: Jae Won
authors.initials: JW
authors.lastname: Lee
authors.forename: Woo Ju
authors.initials: WJ
authors.lastname: Jeong
authors.forename: Sung Yul
authors.initials: SY
authors.lastname: Park
authors.forename: Enrique I S
authors.initials: EI
authors.lastname: Loreazo
authors.forename: Cheol Kyu
authors.initials: CK
authors.lastname: Oh
authors.forename: Koon Ho
authors.initials: KH
authors.lastname: Rha