Use of robotic prostatectomy has mushroomed in the United States, but new data suggest it is best left in the hands of expert surgeons.
A multicenter analysis of 3,794 cases of robotic-assisted laparoscopic radical prostatectomy (RALP) performed by three experienced surgeons found that at least 1,500-1,600 cases were needed to achieve a positive surgical margin (PSM) rate of less than 10%, which is widely accepted in the surgical literature as a sign of excellence.
"We recommend that this operation should not be done by all urologists in small community hospitals, but should be focused and concentrated into those high-volume centers of excellence where the operation can be done by surgeons doing a large number of cases, very frequently, in order that they can achieve the best possible cancer-control results for their patients," lead author Dr. Prasanna Sooriakumaran said during a Feb. 15 press briefing for a symposium on genitourinary cancers.
Of the roughly 90,000 radical prostatectomies performed each year in the United States to treat prostate cancer, more than 70,000 are robot assisted and more than 70% of these are performed by surgeons who do fewer than 100 cases of RALP per year, he said.
The growing popularity of RALP was stoked by reports that the learning curve with regard to safety is around 25-40 cases. There is no good evidence in the literature, however, as to how long it takes to achieve expert level or optimal results for the patient, said Dr. Sooriakumaran, a visiting fellow in urology at the Weill Cornell Medical College in New York.
The researchers divided the cases based on surgeon experience, beginning at fewer than 50 cases and progressing to more than 1,000 cases performed. The median preoperative prostate-specific antigen level (range 4.7-5.4 ng/mL) and median age at surgery (range 60-61 years) remained relatively constant with increasing surgeon experience.
As surgeon experience increased, however, the number of patients with high-grade cancer, defined by a Gleason score of more than 7, decreased from 8.2% to 5.6%, and the number of patients with extracapsular invasion or pT3 disease decreased from 27% to 16%, suggesting that patients should have better results since the cases were getting more curable with time, Dr. Sooriakumaran said.
PSM rates for all patients start off at about 20% when surgeons begin learning the procedure, and it takes about 1,500-1,600 cases for margin rates to reach less than 10%. Notably, margin rates continue to fall beyond 1,600 cases, suggesting that the learning curve continues, even when PSM rates fall below 10%, he said.
When only patients with pT3 disease were evaluated, the learning curve starts to plateau after 1,000-1,500 cases, which is to be expected because these patients have prostate cancer outside the prostate, and therefore an operation to simply remove the prostate is more likely to leave cancer cells behind, Dr. Sooriakumaran said.
Operating times for the three surgeons started off at 3 hours and plateaued at around 2 hours after 750-1,000 cases, regardless of whether patients had extracapsular extension or not.
When asked how surgeons at community hospitals should gain experience if the procedure is limited to high-volume centers, Dr. Sooriakumaran said there has to be a balance and likened the situation to what is occurring with laparoscopic radical prostatectomy, which was popularized in the United States but was found to be a difficult operation to perform safely and is now done by only a few expert surgeons.
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