Randomized Controlled Feasibility Trial of Robot-assisted Versus Conventional Open Partial Nephrectomy: The ROBOCOP II Study

Abstract

Background: There is no evidence from randomized controlled trials (RCTs) comparing robot-assisted partial nephrectomy (RAPN) and open partial nephrectomy (OPN).

Objective: To assess the feasibility of trial recruitment and to compare surgical outcomes between RAPN and OPN.

Design, setting, and participants: ROBOCOP II was designed as single-center, open-label, feasibility RCT. Patients with suspected localized renal cell carcinoma referred for PN were randomized at a 1:1 ratio to either RAPN or OPN.

Outcome measurements and statistical analysis: The primary outcome was the feasibility of recruitment, assessed as the accrual rate. Secondary outcomes included perioperative and postoperative data. Data were analyzed descriptively in a modified intention-to-treat population consisting of randomized patients who underwent surgery.

Results and limitations: A total of 50 patients underwent RAPN or OPN (accrual rate 65%). In comparison to OPN, RAPN had lower blood loss (OPN 361 ml, standard deviation [SD] 238; RAPN 149 ml, SD 122; difference 212 ml, 95% confidence interval [CI] 105-320; p < 0.001), less need for opioids (OPN 46%; RAPN 16%; difference 30%, 95% CI 5-54; p = 0.024), and fewer complications according to the mean Comprehensive Complication Index (OPN 14, SD 16; RAPN 5, SD 15; difference 9, 95% CI 0-18; p = 0.008). OPN has a shorter operative time (OPN 112 min, SD 29; RAPN 130 min, SD 32; difference -18 min, 95% CI -35 to -1; p = 0.046) and warm ischemia time (OPN 8.7 min, SD 7.1; RAPN 15.4 min, SD 7.0; difference 6.7 min, 95% CI -10.7 to -2.7; p = 0.001). There were no differences between RAPN and OPN regarding postoperative kidney function.

Conclusions: This first RCT comparing OPN and RAPN met the primary outcome of the feasibility of recruitment; however, the window for future RCTs is closing. Each approach has advantages over the other, and both remain safe and effective options.

Patient summary: For patients with a kidney tumor, open surgery and robot-assisted keyhole surgery are both feasible and safe approaches for partial removal of the affected kidney. Each approach has known advantages. Long-term follow-up will explore differences in quality of life and cancer control outcomes.

Keywords: Evidence-based medicine; Kidney cancer; Partial nephrectomy; Randomized controlled trial; Robotic surgery.