“The value of robotic laparoscopic radical prostatectomy: Important vs. minimal use."
Laparoscopic or Robotic Prostatectomy – Not There Yet
Stacy Loeb, M.D.1and William J.Catalona, M.D.2
1 Department of Urology, Georgetown University School of Medicine, Washington, D.C.
2 Department of Urology and the Robert H. Lurie Comprehensive Cancer Center, Northwestern University Feinberg School of Medicine, Chicago, IL
Supported in part by the Urological Research Foundation
William J. Catalona, M.D.
675 North St. Clair Street
Chicago, IL 60611
Key Words: Prostate cancer, radical prostatectomy, retropubic, laparoscopic, robotic
Since the 1990’s, several new techniques of performing radical prostatectomy have become available. Although the standard open operation is still the most widely used technique, laparoscopic or robotic-assisted laparoscopic techniques have gained popularity, due in part to aggressive marketing inducing consumer demand. In the senior author’s opinion, the laparoscopic and robotic prostatectomy have not been proven to be as effective as the traditional open operation. More specifically, they are not as effective as the traditional open prostatectomy for simultaneously accomplishing the sometimes-competing goals of complete removal of cancer and preserving potency.
The goal of laparoscopic or robotic prostatectomy has been to attempt to apply “minimally invasive” techniques that have been used successfully in other surgical operations to the treatment of prostate cancer.
Enthusiasts of the laparoscopic or robotic procedure claim it is less invasive and has a quicker recovery time. However, laparoscopic prostatectomy – particularly when performed transperitoneally- is really more invasive than an open extraperitoneal approach. Entering the peritoneal cavity may complicate future intra-abdominal surgery, and carries with it greater risks for injury to the bowel, major blood vessels and the ureters, as well as urine peritonitis and later intestinal obstruction from adhesions.
Furthermore, the physiologic response to the “minimally invasive” techniques does not appear to differ considerably from that of the standard open operation. Fornara et al. compared the serum levels of acute phase reactants, such as C-reactive protein and interleukin-6, between laparoscopic and open prostatectomy and found no significant difference.
A laparoscopic or robotic prostatectomy typically involves 5 or 6 ports, each requiring an incision of about 1 inch in length. By contrast, an open radical prostatectomy involves one vertical or horizontal incision, currently usually 4 to 5 inches in length, depending upon the patient’s body habitus. A perineal prostatectomy involves a small incision in a region that is seldom visible. The effect of these differences on patient quality of life is unproven.
Postoperative Pain and Return to Normal Activity
Differences in the size and number of incisions also do not appear to translate into significant differences in postoperative pain, duration of hospitalization or return to normal activities.
Visualization of the Operative Field
Another often-cited advantage of laparoscopic or robotic prostatectomy is improved visualization through greater magnification than can be achieved with open surgery. However, excellent magnification can be provided with open surgery through the use of surgical loupes, and the small difference between them has not been shown to have a material effect on the surgical outcomes. Some proponents of laparoscopic approaches have argued that better visualization facilitates the preservation of potency and urinary continence or makes it easier to perform a secure vesicourethral anastomosis. However, the potential advantages are offset by the objective disadvantage of the more limited access provided by laparoscopic approaches. Overall, laparoscopic and robotic prostatectomy have not been shown to significantly improve potency, continence, or anastomotic leak rates as compared to open surgery.
Preservation of Urinary Continence
In the senior author’s series and that of Walsh et al., urinary continence was preserved in 93% of men. Although differences in surgeon experience and patient characteristics can confound direct comparisons of surgical series, most studies to date have shown either similar or inferior continence results with laparoscopic techniques.
In performing the vesicourethral anastomosis, it is generally more difficult to place the anastomotic sutures in the urethral stump using laparoscopic techniques. It is also more difficult to dissect the bladder neck free from the prostate and to reconstruct the bladder neck than it is with open surgery, where the ability to palpate the junction of the bladder and the prostate and the ready ability to place reconstructive sutures is far greater. Accordingly, nearly all laparoscopic or robotic surgeons have adopted a bladder neck-sparing approach to avoid having to reconstruct the bladder neck. Because it is more difficult to identify the bladder neck laparoscopically, the laparoscopic bladder neck-sparing approach carries a greater risk for leaving prostate tissue behind on the bladder neck and may increase the risk for positive surgical margins, both of which can cause troublesome postoperative elevations of PSA levels.
Anastomotic urine leaks and vesicourethral anastomotic strictures are more common with laparoscopic or robotic approaches, particularly during the learning curve phase. The running anastomotic suture technique frequently used with laparoscopic or robotic techniques to avoid leaks may result in ischemia in the urethral tissues and result in vesicourethral anastomotic strictures.
Pelvic Lymph Node Dissection
Pelvic lymph node dissection is more difficult to perform with laparoscopic or robotic surgical techniques. Consequently, laparoscopic surgeons frequently do not perform a staging pelvic lymphadenectomy as a part of the radical prostatectomy.
Preservation of Erectile Function
The senior author believes that with the robotic or laparoscopic prostatectomy, the surgeon is often forced to make a more stark choice between removing all of the cancer and preserving the neurovascular bundles to maintain potency. A greater likelihood of accomplishing both goals simultaneously is provided with the increased access of the open approach. In the senior author’s open RRP series, potency was preserved in 76% of preoperatively potent men who underwent bilateral nerve-sparing surgery. This included 93% of men younger than age 50 years, 85% ages 50 to 59, 71% ages 60 to 69, and 52% ages 70 and above. Using the same criteria (preoperatively potent, bilateral nerve-sparing) in a laparoscopic series, Rassweiler et al. reported potency rates of 78% for men younger than 55 years old, 60% for ages 55 to 65, and 43% for men over age 65.
An important limitation of laparoscopic and robotic approaches in preserving potency is gaining adequate hemostasis in the neurovascular bundles without using electrocautery or thermal energy. With open prostatectomy, the prostate is sharply dissected away from the neurovascular bundles without electrocautery or thermal energy, and bleeding vessels can be readily secured with fine, precisely placed hemostatic clips or absorbable, delicate sutures. The sutures are absorbed after several weeks, leaving the neurovascular bundles viable and able to recover from minor surgical trauma.
By contrast, with the laparoscopic or robotic approach, it is far more difficult to quickly and accurately apply hemostatic clips or place hemostatic sutures. Therefore, many laparoscopic surgeons unfortunately resort to bipolar or unipolar electrocautery or a harmonic scalpel for hemostasis when bleeding from the neurovascular bundles becomes troublesome. As a result, the prostate gland and the adjacent neurovascular bundles often become charred and desiccated from the high temperatures, irreversibly damaging them and resulting in permanent erectile dysfunction.
Attempts to instead dissect the prostate further away from the neurovascular bundles by establishing the plane of dissection more medially and/or anteriorly (as with preservation of the “Veil of Aphrodite”) could potentially result in dissecting into and through the prostatic capsule, with a risk of spilling tumor cells into the periprostatic tissues and having positive surgical margins.
Some laparoscopic surgeons also have reported topical application of hemostatic agents to the neurovascular bundles, but the efficacy and safety of these agents has not yet been demonstrated convincingly. Nevertheless, it is possible that future modifications and improvements to laparoscopic technique may help to improve the preservation of potency.
Another significant limitation of laparoscopic and robotic prostatectomy is the lack of tactile feedback, which is an important component of open surgery. The robot lacks the “human touch” and it is not possible for the surgeon to appreciate how the prostate gland feels and how readily it separates from the neurovascular bundles or other surrounding tissues. Because with laparoscopic or robotic surgery, the surgeon largely forgoes the primary sense of touch, he or she must learn to rely more heavily on the sense of sight.
Furthermore, with the robot or with laparoscopic instruments, the prostate gland cannot be retracted and manipulated as gently as with the human hand. Thus, the robot and other laparoscopic instruments that do not provide fine tactile feedback may inadvertently puncture the capsule of the prostate, leading to spillage of tumor cells and positive surgical margins. Furthermore, the prostate may be unintentionally torn away from the neurovascular bundles in a rough manner producing a stretch injury-related nueuropraxia.
Researchers from the Cleveland Clinic have suggested the use of intraoperative transrectal ultrasonography as a way to help offset the lack of tactile feedback in laparoscopic cases. They have reported that it is useful both in neurovascular bundle preservation and to examine for hypoechoic areas or abnormalities in the prostate contour that might be suggestive of extracapsular tumor extension. Despite their encouraging preliminary results, there is no real substitute for human touch. Furthermore, other steps such as retraction, dissection, suturing and knot tying are all facilitated by the familiar tactile sensation.
An advantage of laparoscopic or robotic prostatectomy is that the pneumoperitoneum should assist with hemostasis, theoretically leading to less intraoperative blood loss. Nevertheless, the clinical significance of this is unclear, since autologous transfusions are seldom required using open or laparoscopic techniques, and studies have failed to demonstrate a significant difference between them. For example, in the comparative study by Rassweiler et al., intraoperative autologous transfusions were given in 8.9% of laparoscopic and 6.6% of open cases. With an experienced surgeon, few patients require blood transfusions from another person using either technique.
The complications with laparoscopic or robotic prostatectomy tend to be more serious than with open prostatectomy, and anecdotal evidence suggests that postoperative emergency room visits, repeat hospitalizations, and re-operations are all more common in laparoscopic cases.. In one study, Rassweiler et al. reported on a comparison of complication rates in 1243 open and 1243 laparoscopic radical prostatectomies in Germany. Major complications occurred in 10.7% and 12.3% of cases, respectively. In another series, Hu et al. compared the complications among 358 laparoscopic and 322 robotic radical prostatectomies. They reported perioperative complications in 27.7% of laparoscopic and 14.6% of robotic prostatectomies, including intraoperative ureteral, rectal, vascular, and nerve injuries. Postoperative ileus delaying discharge was reported in 28 patients, and there were 7 cases of rectourethral fistula.
Because follow-up is not yet mature to evaluate cancer cure rates with laparoscopic or robotic surgery, surgical margin status has been used as a surrogate pathological marker to compare cancer control between laparoscopic and open techniques. Indeed, positive surgical margins are associated with significantly higher rates of biochemical progression, clinical progression and death.
Particularly early in the learning curve, positive margin rates in several laparoscopic prostatectomy series are concerningly high. For example, Atug et al. reported a positive margin rate of 45.4% in the first 33 of 100 consecutive robotic prostatectomies, including 10 of 26 patients (38.4%) with pathologically organ-confined disease. In the next 33 patients and the final 34 patients, the positive margin rates decreased to 21.2% and 11.7%, respectively. Nevertheless, as Baumert pointed out in an editorial comment, “the positive margin rate of the first group of patients is difficult to accept in this day and age. All teams new to robotic or laparoscopic surgery should initiate their programs with mentors to avoid ‘sacrificing’ the first patients.”
The learning curve involved in laparoscopic prostatectomy is a well-described disadvantage of the technique. According to one estimate, it takes at least 40 to 60 cases for an experienced open surgeon to become proficient. Proponents of robotic prostatectomy have shown that the robot may decrease the learning curve for inexperienced laparoscopic surgeons to become proficient with the technique. Nevertheless, there is clearly an inherent compromise of the initial patients being treated with these techniques.
Fortunately, the current endoscopic equipment is useful in the instruction of these techniques, such that even the second assistant has an excellent magnified view of the anatomy and technique. Unfortunately, for practicing urologists who are adept in open radical prostatectomy, participation in such hands-on training courses requires a sacrifice of time and finances. Moreover, formal training in such complicated urological procedures is not yet uniformly available in residency training programs.
Long-Term Cancer-Free Survival Results
Most importantly, the laparoscopic and robotic prostatectomy have no track record in terms of long-term cancer control. The surgical specimen is generally removed from a port site within an entrapment sac and no port site recurrences have yet been described. Nevertheless, the positive margin rates are concerning, and if small amounts of cancer are left behind, it may not become apparent for years. Thus, long-term cancer cure rates are needed to adequately evaluate the effectiveness of the operation. These questions have been well documented for open prostatectomy.
Guillonneau et al. reported three-year biochemical progression-free survival rates for LRP of 92% for pT2a, 88% for pT2b, 77% for pT3a, and 44% for pT3b, for an overall rate of 90.5%; however, for prostate cancer, 3-year biochemical recurrence-free rates are not meaningful. For comparison, in 2404 men treated by RRP, Han et al. reported 5-year isolated PSA, local, and distant recurrence-free survival rates of 92%, 99%, and 96%, respectively. It remains to be demonstrated whether laparoscopic and robotic techniques afford similar long-term survival results.
Although the robot may facilitate the operation for urologists without advanced laparoscopic experience, it is extremely expensive, potentially limiting its widespread applicability. In addition to the cost of the equipment, laparoscopic and robotic techniques are associated with a considerably longer operative time. Van Appeldorn et al. reported an operative time of 292 minutes in the first 20 patients, which was reduced to 191 minutes once they reached patients 130-150. Although increasing experience with the technique does reduce the operative time, it remains at the upper limit of what is typically reported in open prostatectomy series.
Finally, Lotan et al. estimated that conventional laparoscopic and robotic prostatectomy increase the cost by $487 and $1726, respectively, over open radical prostatectomy. Based on the data to date, laparoscopic approaches are associated with a similar short-term recovery to open prostatectomy, a higher proportion of major complications, and uncertain long-term cancer control outcomes. To warrant such a significant increase in cost, laparoscopic approaches should offer a clear advantage over open prostatectomy, and the existing evidence does not show this to be the case.
The senior author does not believe that laparoscopic or robotic prostatectomy prostatectomy is as safe a cancer operation as open radical prostatectomy, or that nerve-sparing can be as readily or safely accomplished. The overly hasty and widespread adoption of this technique could set the field of early prostate cancer detection and treatment back 15 years as did the early application of ineffective open brachytherapy techniques in the 1970s.
Keeping all of the above in mind, the most important factor in the safety and efficacy of radical prostatectomy is the surgeon and not necessarily the technique.