CHICAGO—Robotic-assisted laparoscopic prostatectomy is either an engineering marvel that accelerates surgical time and lessens sexual dysfunction, or a cost-inefficient technology with a steep learning curve. It depends on who is speaking.
The topic was debated here by two speakers at the 10th Annual Windy City “Shoot-Out” about controversies about early-stage prostate cancer.
Radical retropubic prostatectomy can match robotic-assisted laparoscopic prostatectomy in cancer control and preservation of continence and potency, said Gregory P. Zagaja, MD, Assistant Professor of Surgery at the University of Chicago.
Furthermore, he said, there are no significant differences between the two modalities in pain, hospital stay, transfusion rate, catheter dwell time, or complications.
However, the surgical technique for radical retropubic prostatectomy has now reached a plateau, he said. “This is perhaps where robotic prostatectomy is going to step in and help things.”
The other speaker in the session, Timothy G. Wilson, MD, Director of the Department of Urology at City of Hope Cancer Center, which has three da Vinci surgical robotic systems, said he did not entirely agree. For one thing, sexual dysfunction is likely to be significantly less after a robotic-assisted laparoscopic prostatectomy, he noted.
“You see the nerves better, and because of the magnification and the way the wrist action of the robotic device works, you can do a better nerve-sparing procedure. Ultimately, sexual dysfunction will be less.”
Cancer-control rates should be identical between the two modalities, Dr. Wilson added, but robotic systems are associated with similar or improved operative times compared with radical retropubic prostatectomy, decreased blood loss, and a quicker return to continence.
Surgical Margins Key
The most important issue, Dr. Zagaja said, is not whether the doctor is using a robot or a scalpel, but rather, the surgical margins that often result from an extraprostatic tumor extending beyond the limits of resection.
Positive surgical margins average 25% to 30% in most series, he continued, and are an issue because approximately 30% of men develop recurrent disease and require additional treatment. Surgical margin data on robotics are not mature.
To reduce positive surgical margins with traditional radical retropubic prostatectomy, Dr. Zagaja modified his surgical approach. At the University of Chicago, 965 patients underwent radical retropubic prostatectomy between 1994 and 2004. Only 20 (2%) had an isolated positive apical margin, and only 83 (8.6%) had a positive surgical margin at any site.
Data on robotic surgery report up to 35% positive surgical margins, he said, citing a 2003 study in the Journal of Urology.
The loss of tactile sensation with robotics could increase the risk of positive surgical margins, Dr. Zagaja noted. “Early on when you're using the equipment, you don't know the pressure the equipment is exerting on the tissue.”
Major academic centers around the country report comparable rates of negative surgical margins with traditional radical retropubic prostatectomy, he said, noting studies at Baylor College of Medicine (87% rate) and Johns Hopkins (85%).
Early data suggest that robotic-assisted laparoscopic prostatectomy may be equally effective in cancer control, but the data need to mature, he said. “There is no biochemical disease-free data available at this time.”
Continence is an issue with radical prostatectomy, but surgical modifications can improve that too, Dr. Zagaja said.
Conservation of sexual potency depends on patient age and the preservation of neurovascular bundles. Dr. Zagaja cited studies showing that 91% of patients under age 50 had preservation of sexual potency with traditional radical prostatectomy vs 82% of patients between 50 and 60 with robotic surgery.
Operative time between the two modalities cannot be compared because of the immaturity of data on robotics. Standard open radical retropubic prostatectomy takes 120 to 150 minutes.
For robotic-assisted laparoscopic prostatectomy, it is considered that 30 to 40 cases are required before the procedure can be performed in less than 240 minutes, and 40 to 50 cases are needed before it can take less than 180 minutes.
Cosmesis is comparable between the two modalities, as is the transfusion rate and the duration of catheterization, Dr. Zagaja said, but not cost.
According to Intuitive Surgical, the company that makes the da Vinci robotic system, the equipment costs $1.3 million, with an annual maintenance contract of $129,000. On top of this are the additional costs of products disposed of after each surgery, such as ports, robotic instruments, and laparoscopic scissors.
According to Dr. Zagaja, based on current robot costs, no decrease in the length of stay or operating room time would make robotic surgery cost equivalent to traditional radical prostatectomy. Robot-assisted laparoscopic prostatectomy only begins to be cost effective when the robot's price decreases to $500,000 and the service contract to $34,000 a year with disposables at $500.
Dr. Zagaja concluded that cancer control appears equivalent with the two modalities, as do continence and potency preservation. He said he does not believe that robot-assisted laparoscopic prostatectomy is feasible and reproducible in the majority of practices, not only because of the cost, but because of the time and effort required to get the program started.
He also questioned whether the procedure's benefits outweighed the human costs of the learning curve.
Dr. Wilson noted data presented at this year's American Urological Association meeting on 450 patients who had undergone robotic prostatectomy with an average estimated blood loss of only 47 cc per patient and an average operating room time of 131 minutes. Positive margins occurred in 10.5% of patients.
Dr. Wilson conceded, however, that the learning curve with robotic prostatectomy was steep, and noted data showing a marked improvement after the first 40 patients.
A majority of Dr. Wilson's presentation involved data from City of Hope. “Currently we do 100% da Vinci protocol,” he said. “No lap cases [i.e., laparoscopic prostatectomy], unless there is a case of computer malfunction—literally, the robot crashes.”
Regarding the experience with 714 patients at City of Hope, the mean operating time was 4.4 hours for laparoscopic prostatectomy and 3.2 hours for robotic.
The median estimated blood loss in these groups was 252 cc for laparoscopic vs 291 cc for robotic. The length of stay was under two days for 231 patients in the laparoscopic group and 304 patients in the robotic group.
In a study of 306 patients who underwent laparoscopic surgery, the median time to continence was 116 days vs 44 days for a group of 141 patients who underwent robotic surgery.
Potency recovery after one year was seen in 100% of men after robotic surgery.
Dr. Wilson said that oncological outcomes were the same with both procedures and that potency returned earlier after robotic surgery. He also suggested that robotic prostatectomy was superior to laparoscopic in complication rates, secondary to the learning curve.
He cited data from a prospective study from another single institution, the Vattikuti Urology Institute of the Henry Ford Health System in Detroit, as well as one surgeon's experience (Urology 2004;63:1224–1228). Thomas Ahlering, MD, of the University of California, Irvine, completed the learning curve and then compared two groups of 60 patients undergoing either robotic or radical retropubic prostatectomy.
The estimated blood loss in the radical prostatectomy group was 418 vs 103 cc for the robotic group. “I think it's the main reason that men recover more quickly,” Dr. Wilson said.
With experience, operative times are similar or improved by using a robot, he said. Blood loss is routinely less, as is the length of hospital stay and catheter time, although the latter two are insignificant.
The overall complication rate between radical and robotic prostatectomy is not significantly different, but continence returns earlier after robotic surgery, and robotic techniques, technology, and instrumentation will only improve with time, he said.