The learning curve of robot-assisted radical cystectomy: Results from the international robotic cystectomy consortium

Background: Robot-assisted radical cystectomy (RARC) has evolved as a minimally invasive alternative to open radical cystectomy for patients with invasive bladder cancer. Objective: We sought to define the learning curve for RARC by evaluating results from a multicenter, contemporary, consecutive series of patients who underwent this procedure. Design, setting, and participants: Utilizing the International Robotic Cystectomy Consortium database, a prospectively maintained and institutional review board-approved database, we identified 496 patients who underwent RARC by 21 surgeons at 14 institutions from 2003 to 2009. Measurements: Cut-off points for operative time, lymph node yield (LNY), estimated blood loss (EBL), and margin positivity were identified. Using specifically designed statistical mixed models, we were able to inversely predict the number of patients required for an institution to reach the predetermined cut-off points. Results and limitations: Mean operative time was 386 min, mean EBL was 408 ml, and mean LNY was 18. Overall, 34 of 482 patients (7%) had a positive surgical margin (PSM). Using statistical models, it was estimated that 21 patients were required for operative time to reach 6.5 h and 8, 20, and 30 patients were required to reach an LNY of 12, 16, and 20, respectively. For all patients, PSM rates of <5% were achieved after 30 patients. For patients with pathologic stage higher than T2, PSM rates of <15% were achieved after 24 patients. Conclusions: RARC is a challenging procedure but is a technique that is reproducible throughout multiple centers. This report helps to define the learning curve for RARC and demonstrates an acceptable level of proficiency by the 30th case for proxy measures of RARC quality.