Robotic vs. open RP: Experts react to first randomized trial

The first published randomized controlled trial comparing robot-assisted laparoscopic prostatectomy (RALP) with open radical retropubic prostatectomy (ORPP) found no statistically significant differences between the two procedures in primary outcomes analyses of standard oncologic and functional parameters at 12 weeks.

Urology Times reached out to several key opinion leaders for their interpretation of the results. Their analyses centered on postoperative complications between the surgical approaches, the need to account for findings from other studies, oncologic outcomes, and cost differences.

Follow-up is now continuing in this single-center Australian study in which the procedures were performed by two surgeons, and functional outcomes and disease progression will be assessed at 24 months.

The study was powered to assess health-related and domain-specific quality of life outcomes over 24 months, and it enrolled men ages 35 to 70 years choosing surgery for treatment of newly diagnosed clinically localized prostate cancer; 157 men underwent RALP and 151 men had ORPP.

As reported in the paper, which was published online in The Lancet (July 26, 2016), there were no statistically significant differences between surgical groups at 6 weeks or 12 weeks in mean scores for urinary function (urinary domain of EPIC) or sexual function (EPIC sexual domain and IIEF total score) nor in rates of positive surgical margin status (RALP, 15% vs. ORPP, 10%).

A review of perioperative outcomes showed statistically significant differences favoring RALP over ORPP for the intraoperative adverse event rate (2% vs. 8%), estimated blood loss (443.74 mL vs. 1338.14 mL), and hospital stay (1.55 vs. 3.27). RALP had a lower postoperative complication rate than the open procedure (4% vs. 9%), but the difference was not statistically significant. There were also no statistically significant differences between groups in rates of blood transfusion, intensive care unit admission, hospital readmission, or indwelling catheter days. Mean scores for pain during activities and worst pain were significantly lower in the RALP group at day 1 and week 1, but not at later follow-up.

Next: Drs. Koch, Menon, Nelson discuss study

Speaking with Urology Times about the study, Michael Koch, MD, noted that just as when comparing other types of surgeries, the major difference between open and minimally invasive procedures was in the postoperative complication rate.

“While the rate was almost twofold higher in the open prostatectomy group, the difference failed to achieve statistical significance, probably due to the relatively small sample size,” said Dr. Koch, of Indiana University School of Medicine, Indiana.

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Mani Menon, MD, said that the findings of this well-designed study are consistent with previous research showing that RALP fulfills three important goals of minimally invasive surgery; ie, it reduces blood loss, postoperative pain, and complications compared with open surgery. The absence of any differences in early functional outcomes in this study, however, is at odds with longer term results from meta-analyses and comparative effectiveness studies, he said.

“Before making definitive conclusions, it may be prudent to consider all of the available evidence in the field, rather than results from a single surgical group or using a particular analytic approach,” said Dr. Menon, of Vattikuti Urology Institute, Henry Ford Health System, Detroit.

Joel Nelson, MD, said that the paper supports what most experienced prostatectomy surgeons already know, and that is that ORPP and RALP result in the same functional outcomes and also the same oncologic outcomes assuming both approaches remove the entire gland.

He noted that use of cell salvage eliminates any disadvantage of ORPP for causing more blood loss. Importantly, a comparison of financial impact is missing in the study’s analyses, observed Dr. Nelson, of the University of Pittsburgh School of Medicine.

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“In a setting of outcome equivalence between the two approaches, the value of the more expensive robotic approach is appropriately questionable,” he said.

Next: Drs. Andriole, Lepor on the findings

In reviewing the paper, Gerald L. Andriole, MD, focused on the oncologic outcomes.

“That is the reason men choose to undergo surgery for prostate cancer, and as I and many others would have anticipated, open prostatectomy was superior to the robotic technique at achieving negative surgical margins overall and especially for men who had more advanced (≥T3) disease (92% vs. 89%),” he said.

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Suggesting that the absence of a statistically significant difference in surgical margin status reflected sample size, Dr. Andriole said the difference is concerning considering that today, more men undergoing prostatectomy have locally advanced tumors.

“Time will tell, but the higher rate of positive margins with the robotic technique may well be a harbinger of later disease recurrence and the need for additional treatment,” said Dr. Andriole, of Washington University School of Medicine, St. Louis.

Noting that quality of life and oncologic control are the most important outcomes following radical prostatectomy, Herbert Lepor, MD, highlighted the absence of statistically significant between-group differences in the early sexual and urinary function scores. However, he also cited the 50% increase in positive margin rate in the robotic group as worrisome, and he downplayed the statistically significant differences in pain scores as being clinically insignificant (mean difference of about 1 point on a 10-point scale).

“The robotic approach must be unequivocally superior to open surgery in order to justify its learning curve and higher cost. We can quibble over details, but this study provides compelling evidence that the robotic approach is clearly not superior. If it was performed a decade ago, payers would not pay for the robot, nor would patients demand the procedure,” said Dr. Lepor, of New York University Langone Medical Center, New York.

More on Prostate Cancer:

Prostate biopsy-related infections raise transfusion risk

Data offer new insight on HIFU’s use in low-risk PCa

Use of observation for PCa varies widely among urologists

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