The learning curve for laparoscopic radical prostatectomy: an international multicenter study

Abstract

Purpose: It is not yet possible to estimate the number of cases required for a beginner to become expert in laparoscopic radical prostatectomy. We estimated the learning curve of laparoscopic radical prostatectomy for positive surgical margins compared to a published learning curve for open radical prostatectomy.

Materials and methods: We reviewed records from 8,544 consecutive patients with prostate cancer treated laparoscopically by 51 surgeons at 14 academic institutions in Europe and the United States. The probability of a positive surgical margin was calculated as a function of surgeon experience with adjustment for pathological stage, Gleason score and prostate specific antigen. A second model incorporated prior experience with open radical prostatectomy and surgeon generation.

Results: Positive surgical margins occurred in 1,862 patients (22%). There was an apparent improvement in surgical margin rates up to a plateau at 200 to 250 surgeries. Changes in margin rates once this plateau was reached were relatively minimal relative to the CIs. The absolute risk difference for 10 vs 250 prior surgeries was 4.8% (95% CI 1.5, 8.5). Neither surgeon generation nor prior open radical prostatectomy experience was statistically significant when added to the model. The rate of decrease in positive surgical margins was more rapid in the open vs laparoscopic learning curve.

Conclusions: The learning curve for surgical margins after laparoscopic radical prostatectomy plateaus at approximately 200 to 250 cases. Prior open experience and surgeon generation do not improve the margin rate, suggesting that the rate is primarily a function of specifically laparoscopic training and experience.

Figure 1

Surgical learning curve for SMs with LRP controlling for preoperative PSA, pathological Gleason score and pathological stage. X-axis represents number of cases before incident case, excluding prior open cases. Gray lines represent 95% CI.

Figure 2

Surgical learning curve for SMs with ORP controlling for preoperative PSA, pathological Gleason score and pathological stage. To make open and laparoscopy learning curves more comparable, open cohort was restricted to patients seen after 1995 and model covariates were set to mean of patients in laparoscopy learning curve. Gray lines represent 95% CI.