Learning Curve Accrues More Slowly for Laparoscopic Prostatectomy
By Roxanne Nelson
Medscape Medical News
April 2, 2009 — After a radical prostatectomy, the risk for recurrence is strongly affected by the experience of the operating surgeon. This is true for both open and laparoscopic procedures. However, researchers report that the learning curve for surgery — improvement in surgical outcomes with increasing surgeon experience — appears to accrue more slowly for laparoscopic radical prostatectomy than for open surgery.
The authors of a study published online April 1 in the Lancet Oncology note that surgeons with previous experience in open radical prostatectomy had significantly poorer results than those whose first operation was laparoscopic (risk difference, 12·3%; 95% confidence interval [CI], 8·8–15·7).
"Some clinicians are never going to get up on the learning curve, and that needs to be taken into consideration," said lead author Andrew Vickers, PhD, associate attending research methodologist at Memorial Sloan-Kettering Cancer Center, in New York City. "If they are only doing a handful of radical prostatectomies a year, then they are going to have a hard time getting up on the learning curve. A great deal of surgical experience is required to treat prostate cancer optimally."
A great deal of surgical experience is required to treat prostate cancer optimally.
Dr. Vickers pointed out that it was somewhat surprising that previous open radical prostatectomy experience would lead to poorer outcomes, and that it was a risk factor when it came to performing laparoscopic procedures. "One explanation for this may be that the anatomy looks different when viewed through a laparoscope," he said in an interview. "It may take surgeons a while to adjust from open surgeries."
If the data are replicated, these findings may have important implications for surgical practice, because they suggest that surgeons should not switch back and forth between techniques without a compelling reason to do so, he explained.
Recurrences Decrease With Experience
In a previous study, Dr. Vickers and colleagues found that prostate cancer patients treated by highly experienced surgeons were far more likely to be cancer-free 5 years after surgery than patients treated by surgeons with less experience (J Natl Cancer Inst. 2007;99:1171–1177). The risk for recurrence 5 years after surgery was 17.9% for patients treated by surgeons who had performed 10 previous operations and 10.7% for those treated by surgeons who had performed 250 previous surgeries.
The probability of cancer recurrence after laparoscopic radical prostatectomy declined as the experience of the operating surgeon increased, the researchers note in the current study, but surgical outcome seemed to improve more slowly for laparoscopic than for open surgery.
The researcher conducted a retrospective multicenter cohort study of 4702 patients with prostate cancer treated laparoscopically between January 1998 and June 2007. They used multivariable models to assess the association between surgeon experience at the time of each surgery and prostate cancer recurrence, adjusted for established predictors.
There were a total of 402 biochemical recurrences, with a 5-year recurrence-free probability of 82% (95% CI, 80–84), with a median follow-up of 1.7 years.
Risk for Recurrence at 5 Years*
| Previous Laparoscopic Procedures Performed, n |
Risk for Recurrence |
| 10 |
17% |
| 250 |
16% |
| 750 |
9% |
*Model adjusted for case mix
Their analysis showed that surgeons had to perform approximately 750 laparoscopic surgeries before they achieved the same low level of disease recurrence as other surgeons achieved after 250 traditional operations.
More Data Needed
According to the authors, there are a number of possible explanations for this observation. One is that laparoscopic radical prostatectomy may be inherently more difficult to learn. Another reason is that in addition to increasing experience of an individual surgeon, the laparoscopic learning curve may reflect profession-wide modifications to the technique. Open radical prostatectomy is a relatively mature procedure, they write, whereas laparoscopy is a much more recently developed surgical technique.
"Our data raise some important questions," said Dr. Vickers. "Surgeons commonly switch between techniques, but our data showed that a danger was associated with that. The surgical community needs to decide whether or not surgeons should switch techniques."
"We also report an 8% difference in recurrence rates between experienced and inexperienced surgeons," he added. "Experienced surgeons have lower recurrence rates, so we need to learn what they are doing differently."
The study was funded by the National Cancer Institute, the Allbritton Fund, and the David J. Koch Foundation. The researchers have disclosed no relevant financial relationships.
Lancet Oncol. Published online before print April 1, 2009.
