Laparoscopic radical prostatectomy is a difficult operation. As with open surgery, there is a significant learning curve associated with the procedure. The skill required to perform pure laparoscopic prostatectomy puts it beyond all but experienced laparoscopic surgeons. The introduction of the da Vinci robotic surgery system by Intuitive Surgical has made the operation feasible for urologists without formal laparoscopic training and has reduced the length of the learning curve. However, it is clear that with proper training and perseverance, general urologists can also master the pure laparoscopic prostatectomy.^[4] This raises an important question: In the hands of skilled surgeons who have completed the learning curve, is there any advantage to the patient for robotic prostatectomy when compared with pure laparoscopy?

Few studies have directly compared the 2 approaches. Specifically, there have been 3 publications in this area. Tooher and colleagues^[5] reviewed these and found no clinically meaningful differences between the 2 approaches in skilled hands. A closer review of the 3 publications noted significant differences in estimated blood loss, with 2 reports favoring robotic surgery^[6,7] and one favoring pure laparoscopy.^[8] However, when considering differences in blood transfusion rates, the only study that showed a significant difference was the one conducted by the Montsouris Institute, which favored pure laparoscopy.^[8] Although the literature in this area is limited, it seems likely that, in the hands of skilled surgeons, there is no difference in clinical outcomes between robotic prostatectomy and pure laparoscopic prostatectomy. Clearly, the robotic approach shortens the learning curve and makes the operation easier for the surgeon because of the its 3-dimensional stereo-optic visual system, but this results in an advantage for the surgeon, as opposed to the patient, who does not truly benefit from this. Acknowledging that there is no evidence documenting significant differences in clinical outcomes between the laparoscopic approaches, we will group these 2 approaches together when we compare laparoscopic prostatectomy with open surgery.

Surgery for localized prostate cancer has evolved tremendously in the past 25 years. Since Walsh and Donker introduced the nerve-sparing technique in 1982,^[1] radical retropubic prostatectomy has been an increasingly used treatment option. With the advent of prostate-specific antigen (PSA) testing in 1987 and the accompanying increase in newly diagnosed localized cases, urologic surgeons have become quite adept at performing this operation. In the past decade, there has been an increasing push for less invasive techniques for treating prostate cancer. In many respects, this is patient-driven. The first report of minimally invasive laparoscopic prostatectomy, by Schuessler and colleagues, was published in 1997.^[2] This technique did not immediately catch on, in part due to the difficulty of the procedure and in part to the lack of familiarity with laparoscopy on the part of urologists. However, in 2003, after a group at the Montsouris Institute, among others, published their extensive experience, urologists began to embrace the technology.^[3] The technical difficulty of the procedure still prevented many urologists from attempting the operation. Specifically, the laparoscopic intracorporeal knot-tying skills required were beyond the ability of the average urologist in practice. The introduction of the da Vinci robotic surgical system "evened the playing field" and allowed urologists without advanced laparoscopic skills to perform the operation safely.

There is little doubt that more patients are undergoing laparoscopic robotic-assisted prostatectomy than before, but the exact proportion of radical prostatectomies performed in the United States using this approach is unclear at this time. While some of the increased popularity of the robotic approach is justifiably due to the minimally invasive nature of the surgery, there is clearly also an element of marketing involved. Although robotic prostatectomy clearly holds promise in the treatment of localized prostate cancer and likely offers some advantages when compared with open surgery, the claims frequently made on its behalf -- better urinary and sexual outcomes, less pain, better cancer control and an overall superior healthcare experience -- are unsubstantiated. The goal of this article is to review the published evidence and to provide an objective overview of the advantages and disadvantages of laparoscopic robotic prostatectomy when compared with the open procedure.

When comparing these procedures, a number of domains can be considered. These include oncologic outcomes, perioperative complications, "process"- and "recovery"-related variables, functional outcomes, and cost. We will focus on the variables that are most important to patients: oncologic outcomes, "process" and "recovery" variables, and functional outcomes.

In any cancer, the most important outcome is usually either overall- or disease-specific survival. Given that the lead time associated with PSA screening -- the time between when a cancer is detected through PSA screening and when it would be clinically detectable -- has been estimated to be approximately 7 years,^[9,10] one must wait 10-15 years at a minimum in localized prostate cancer to make meaningful comparisons, particularly in low-risk patients. Obviously, laparoscopic prostatectomy has not been practiced long enough for us to make any solid conclusions regarding these outcomes. Some authors have published early results in this area and have shown no difference, but these must be considered preliminary.^[11,12]

Biochemical failure, or rebounding PSA levels, is another proxy outcome that can be used to judge the effectiveness of surgery. Numerous publications have documented that the majority of PSA recurrences following surgery occur within the first 5 years of the procedure, although a small number of patients will recur up to 10 years following prostatectomy.^[13] Direct comparisons of open and laparoscopic prostatectomy must be considered in light of certain limitations. Specifically, many of the open cohorts used for comparison are historical in nature; they occurred earlier in the PSA era and therefore included more patients with generally worse disease. When one controls for pathologic stage and grade, the literature indicates that there are no early differences in recurrence rates, although the number of studies is limited.^[11,12]

Pathologic outcomes are the third and final oncologic variable that can be compared. These variables have the advantage of being immediate and having prognostic significance. Specifically, margin-positive rates are related to surgical technique, among other factors, and provide an important method of comparing the procedures. At first glance, open, pure laparoscopic, and robotic prostatectomy all appear to have similar margin-positive rates.^[11,14] However, as with biochemical failure, the open cohorts come from earlier in the PSA era and generally have higher-volume disease, so one would actually expect the laparoscopic approaches to have slightly better outcomes than the open approach, but this is not the case. In studies directly comparing the 2 techniques, the margin-positive rates are also comparable, but again, the open series were not collected concurrently and the operating surgeons usually had advanced laparoscopic training.^[11,12,15]

In order to level the playing field, it is best to consider margin-positive rates in the hands of expert surgeons in each approach stratified by pathologic stage. When one does this, margin positive rates for pT2 disease appear comparable among the various approaches. However, there appears to be a trend towards lower margin-positive rates for open surgery in pT3a and pT3b disease, as shown in Tables 1 and 2.^[14] This is a very important observation that requires further study.

Lead Author	Type	Sample Size	Margin-Positive Rate	Study Period
Lepor[28]	Open	1000	33.2%	2000-2005
Klein[29]	Open	46	28.2%	1994-1996
Rassweiler[11]	Pure lap	438	37.1%	1999-2002
Guillonneau[3]	Pure lap	1000	31.1%	1998-2002
Menon[30]	Robotic	100	40.0%	2001-2002
Ruiz[31]	Robotic	330	44.3%	1999-2001

Lead Author	Type	Sample Size	pT2b/c	pT3a	pT3b
Rassweiler[14]	Lap	291	5.7%	17.3%	22.5%
Palisaar[32]	Open	723	6.5%/c	10.3%	15.0%

Results are from 2 contemporary European series using different surgical approaches stratified by final pathological stage

In summary, the 2 approaches seem similar in terms of oncologic outcomes in low-risk patients. However, there may be some differences favoring open surgery in high-risk (pT3) patients. Patients should be informed of this and should consider this when choosing a surgical approach.

Process variables (ie, factors relating to the delivery of care) and recovery variables (ie, those relating to convalescence and recovery) also can influence the choice of approach for radical prostatectomy.

According to an analysis by Link and colleagues,^[16] laparoscopic prostatectomy, whether pure or robotic, results in slightly longer operative times than open surgery. This difference, however, may abate or disappear completely as surgeons become more adept at the laparoscopic approaches. While meaningful to the hospital and the doctor, this particular variable likely is not very important to patients (although one could argue that prolonged anesthetic time increases the risk for complications). In addition, hospital length of stay, at least in the United States, is quite short for both procedures. Although the length of stay is significantly shorter for laparoscopy, the actual difference is so small that it may not be important to patients.^[16] Most studies examining length of catheterization fail to find a significant difference between the 2 approaches.^[15,17,18]

Three process/recovery-related variables that are important to patients have been shown to be different among the 2 approaches. First, estimated blood loss is clearly less with the laparoscopic approach, largely because the air circulated into the peritoneal cavity (pneumoperitoneum) prior to and during the procedure effectively tamponades venous bleeding. While the reduced blood loss associated with the laparoscopic procedure may result in patients with more energy and better perceived functional status, this has never been documented in the literature and must therefore be considered a potential benefit at best. What has been documented in the literature is a decreased transfusion rate in laparoscopic surgery. While some studies have estimated this difference to be as great as 45%,^[11] others have failed to show any difference^[15] or even showed an advantage for open surgery.^[19] Some of the difference is due to the use of autologous blood transfusions at certain institutions, which increases the overall risk associated with a transfusion. In a structured review of the literature, it appears that open-surgery patients are more likely to receive a blood transfusion, although this difference is less than 10% (15% vs 9%).^[16] In summary, patients undergoing laparoscopic surgery are less likely to receive a blood transfusion, on average, and this must be considered an advantage to the laparoscopic approach.

The next process/recovery variable which is of concern to patients is the degree of pain experienced postoperatively. It is a common claim that laparoscopic surgery is associated with less postoperative pain than the open procedure, but, in fact, the evidence reveals that the difference in postoperative pain between the 2 approaches is minimal and therefore not a good criterion for choosing between the two. Numerous studies have shown that patients who undergo open surgery have statistically significantly higher pain scores than those who undergo laparoscopic surgery on the day of surgery,^[20,21] but mean scores in both groups are below 3 (on a scale of 0-10), indicating that neither procedure is very painful and that the noted difference many not be clinically significant. Two studies^[17,20] have shown that, by postoperative day 1, the difference in pain scores between the 2 approaches is not statistically significant. Moreover, a number of studies have shown that there is no difference in the amount of morphine sulfate equivalent units required by patients undergoing open and laparoscopic surgery, particularly when one adjusts for the small difference in length of stay.^[17,20] A single study has shown that patients who have undergone open surgery take more oxycodone tablets at home than those who received laparoscopic surgery (17 vs 9 total number of tablets taken during convalescence period), but the significance of this is unclear, given that pain scores are equivalent.^[17] In summary, while there is slightly less pain in the immediate postoperative period for patients undergoing laparoscopic surgery, this difference is minimal and appears to disappear by postoperative day 1. Given these observations, it does not seem legitimate to claim that the difference in pain between the 2 approaches is clinically significant to patients.

The final and perhaps most important process/recovery variable for patients is time to full recovery. While convalescence is relatively short for both procedures, it is clearly shorter for the laparoscopic approach. This is the primary advantage to the laparoscopic approaches, and patients should be informed of this. Two studies have documented a 2-week advantage in time to full recovery for the laparoscopic approach. On average, patients who underwent open surgery were "fully recovered" by 6 weeks, and those who underwent laparoscopic surgery achieved this endpoint by 4 weeks.^[17,22]

Many patients are under the impression that laparoscopic robotic surgery will result in better outcomes with regard to potency and continence. This belief is fueled in part by statements on the medical device maker's and clinicians' Web sites. The evidence does not support these claims.

Studies of sexual function outcomes using validated health-related quality-of-life instruments have failed to show a difference between the open and the laparoscopic approach.^[23] Some single-institution studies of the laparoscopic approach have claimed to demonstrate superiority in this outcome for the laparoscopic approach, but these studies are limited by selection bias and inconsistencies in reporting methods.^[24] When these studies are compared with similar studies from single-institution tertiary referral centers that specialize in open surgery and also have very selected patient populations,^[25] outcomes are quite similar.

Also, in the urinary function domains, numerous studies have failed to show any difference between open and laparoscopic surgery. The single study^[24] that claimed to document an advantage did not use a validated instrument and had significant selection bias, thereby confounding the results. In studies that used validated and reliable instruments and included a more general population of prostate cancer survivors, no differences were noted.^[23]

Another purported advantage of the laparoscopic approach is quicker return of sexual and urinary function. The single-institution study that supposedly documented this was limited by the use of nonvalidated instruments. Another important limitation of this study was that it was based on patient recollection of the experience, which was gathered in a single interview. When postoperative urinary and sexual function was compared using validated instruments with multiple interviews at set timepoints, no differences were noted between the 2 approaches.^[26,27] In fact, there appears to be a trend toward quicker return of potency in the surgical group, although no meaningful conclusions can be drawn from these 2 studies. In summary, the evidence indicates that there are no significant differences in potency or continence outcomes when comparing open and laparoscopic prostatectomy. Furthermore, there is no difference in time to return of continence or potency.

While laparoscopic robotic prostatectomy is appealing to patients for its cutting-edge technology and for being less invasive than the open approach, the evidence to date shows that, in many respects, outcomes following the robotic procedure are quite similar to those following open surgery. From the patient's point of view, robotic prostatectomy offers quicker time to full recovery, a reduced risk for blood loss, and slightly less postoperative pain. However, it does not offer any advantage in functional outcomes, nor does it result in better cancer control. Although some authors claim that outcomes with robotic surgery will improve as practitioners gain experience, studies indicate that the learning curve plateaus after roughly 100-200 cases^[3] and that subsequent improvement is minimal at best. In summary, we must expect that results from high-volume centers represent the state of the art and that, while equivalent outcomes can be achieved with robotic surgery, it is unlikely that they will be superior.

These considerations must be set alongside the potential disadvantages of robotic surgery. Although not discussed in this article, the costs to the healthcare system of this approach are greater, given the fixed cost of the da Vinci system and the costs of disposable and reposable equipment. These factors, while not of concern to the patient, should certainly be a factor in decision-making for institutions considering the acquisition of the da Vinci system. Of course, the primary concern is cancer control and cure. Given the observation that patients with pT3 tumors likely require a more extended lymph node dissection and may also have higher margin-positive rates with robotic surgery, we must decide whether the recovery benefits of the laparoscopic approach outweigh the oncologic risks of the procedure. This author does not believe that this is the case in patients with high-risk disease and does not routinely offer robotic surgery to patients.

The following evidence-based guidelines for use of robotic prostatectomy in localized prostate cancer are suggested:

• "Low-risk" patients: Gleason 6 pts, PSA < 10 ng/mL, cT1 or cT2a:
• Either open or robotic approach is reasonable
• "High-risk patients": Gleason 8-10 pts, PSA > 10 ng/mL, cT2b or higher
• Open approach is preferred
• "Moderate-risk" patients: Gleason 7 pts:
• Optimal approach is unclear and depends upon the surgeon's and patient's preferences. Surgeon should use the approach that he/she is most comfortable with. Another possible approach is to use a nomogram to segregate moderate-risk patients on the basis of 3+4 vs 4+3 disease and risk for pT3 disease.

David F. Penson, MD, MPH Associate Professor of Urology and Preventative
Medicine Keck School of Medicine
USC/Norris Cancer Centre
(323)865-3716
fax (323)865-0120
penson@usc.edu