The RALP learning curve — a case example

We have regularly addressed the  “learning curve” for surgeons who adopt new methods to carry our radical prostatectomies. A recent publication from an Australian group provides specific and useful insight into “early” use of the da Vinci system to carry out robot-assisted laparoscopic prostatectomy (RALP).

Murphy et al. have reported on the operative details and short-term outcomes of the first 400 RALPs performed at their institution (carried out between December 2003 and August 2006). They used a six-port transperitoneal approach with a four-arm da Vinci system  to perform the RALPs. It is important to recognize that this group was not “experimenting with a new technique.” By the time they started to learn how to use the da Vinci system, the effectiveness and utility of the system was well understood (as they themselves acknowledge; see below). The data they report therefore reflects the actual experience of their team in learning how to use a new technology.

The authors developed a prospective database  to record the relevant details of all RALP cases, including the preoperative data on all patients, and then reviewed information in this database to establish the operative details and the oncological and functional outcomes of all patients with a minimum of 12 months follow-up. The short-term functional outcome for each patient was assessed using continence and erectile function questionnaires. Biochemical recurrence (PSA ≥ 0.2 ng/ml) was used as a surrogate marker for cancer control.

They report the following results:

  • The average (mean) age of patients was 60.2 ± 6 years.
  • The patients’ median preoperative PSA level was 7.0 ng/ml.
  • The average (mean) operating time was  186 ± 49 minutes.
  • The overall complication rate was 15.75 percent, comprising Clavien grade I-II and Clavien grade III complications in 10.5 and 5.25 percent  of patients, respectively.
  • The overall positive surgical margin rate was 19.2 percent, with positive margin rates of 9.6 and 42.3 percent in patients with pathological stage T2 and T3, respectively.
  • The biochemical recurrence-free survival was 86.6 percent at a median follow-up of 22 months.
  • At 12 months follow-up, 91.4 percent of patients were pad-free or used a security liner.
  • Of those men previously defined as potent (i.e., having a Sexual Health Inventory for Men  or SHIM score ≥ 21) who underwent nerve-sparing RALP, 62 percent were potent at 12 months.

Making it clear (as indicated above) that the “safety and feasibility of RALP [had] already been established,” the authors conclude that, “Our initial experience with this procedure shows promising short-term outcomes.”

The “New” Prostate Cancer InfoLink would entirely agree with the authors’ conclusion. However:

  • The mean operating time seems long as compared to the operating times reported by surgical teams having earlier and therefore greater experience with RALP.
  • The overall perioperative complication rate seems to be higher than one might like.
  • The rate of positive surgical margins is also higher than those reported by more experienced teams, which may (at least in part) explain a 1-year biochemical disease-free recurrence rate of < 90 percent

This is not in any way a criticism of the surgical team. In the opinion of The “New” Prostate Cancer InfoLink, this reflects a real learning experience in the real world. It takes time to use new technology to its highest levels of potential.

What would be extremely interesting is to see a comparison of these data to precisely analogous data for the next 400 patients treated with RALP by the same team (probably over the following 18 months from September 2006 though mid 2008). Should these data be reported, we would hope to see the operating time come down, the perioperative complication rates lowered, and the positive margin rate come down. We would also expect such improvements to lead to a higher biochemical disease-free recurrence rate at 12 months, as well (perhaps) as to improvements in time to urinary continence and higher percentages of recovery of erectile function in those patients undergoing appropriate nerve-sparing procedures.

One Response

  1. Dr. Declan Murphy, the lead author of the above publication, has kindly provided us with some additional information about this study, as follows:

    1. The Melbourne series now includes > 1000 RALPs and comparisons to the data in this publication should be expected in future publications.
    2. Mean total operative times have not come down much below 3 hours in the longer series. This is largely due to the fact that there are multiple surgeons using the da Vinci in this series, including Fellowship trainees, and so “new people get on the console all the time.” In a teaching hospital setting, new trainees will clearly take longer to complete their initial procedures.
    3. While the positive margin rate in this series is not as low as in some large US series, this is at least partly due to the higher proportion of intermediate and high-risk patients in this series, which reflects the lower PSA screening rates seen in Australia (and most of Europe) than is now normal in the US. However, positive margin rates in the Melbourne series are improving.
    4. One reason that the Melbourne complication rates may seem high is that they have “ruthlessly” applied a validated classification system to the series. The Melbourne group encourages all surgical series to use Clavien grading to monitor complication rates.

    In another paper just published, Caballero Romeu et al. have compared the very earliest learning stages for LRP and RALP to open RRP. It is clear that LRP is the hardest of the three procedures to master.

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