Cumulative summation graphs are a useful tool for monitoring positive surgical margin rates in robot-assisted radical prostatectomy.
OBJECTIVE
• To explore the usefulness of cumulative summation (CUSUM) graphs for monitoring positive surgical margin (PSM) rates during a surgeon's transition from open to robot-assisted radical prostatectomy (RARP).


METHODS
• Data were prospectively collected from patients undergoing RARP by a single surgeon. • Preoperatively all patients were either low or moderate risk under the D'Amico classification system. • A CUSUM graph was charted retrospectively to analyse the PSM rate in patients undergoing RARP for pathological stage T2 (pT2) disease. • Acceptable and unacceptable PSM rates were set at 10% and 15% respectively.


RESULTS
• From a cohort of 226 patients, 158 patients with pT2 disease were selected. The mean (range) age of these patients was 59.2 (39-73) years, the median (range) Gleason score was 6 (4-9), the mean (range) PSA was 6.43 (0.52-17.5) ng/mL and the mean (range) prostate volume was 44 (18-120) cm(3). In all, 21 patients had PSMs (13%). • CUSUM graphs were produced and clearly demonstrated the change in PSM rate over time.


CONCLUSIONS
• CUSUM graphs are a novel and useful visual representation of the learning curve for surgeons. • PSM rates in patients with pT2 disease are a good outcome to monitor using CUSUM graphs as they are binary and lack the confounding factors associated with other outcomes such as continence and erectile dysfunction. • We advocate the use of CUSUM graphs as a method of quality assurance with the introduction of a robotics programme.
Williams
Andrew K
AK
Division of Urology, Department of Surgery, University of Western Ontario, London, ON, Canada.
Chalasani
Venu
V
Martínez
Carlos H
CH
Osbourne
Erica
E
Stitt
Larry
L
Izawa
Jonathan I
JI
Pautler
Stephen E
SE
D000328:Adult; D000368:Aged; D003199:Computer Systems; D004812:Epidemiologic Methods; D006801:Humans; D008297:Male; D008505:Medical Staff, Hospital / Q000193:education; D008875:Middle Aged; D011468:Prostatectomy / Q000193:education / Q000379:methods*; D011471:Prostatic Neoplasms / Q000473:pathology* / Q000601:surgery; D012371:Robotics; D047368:Tumor Burden