Comparative effectiveness of robot-assisted vs. open radical cystectomy.

OBJECTIVES

Over the past decade, robot-assisted radical cystectomy (RARC) has gained traction as an alternative to the conventional open approach open radical cystectomy (ORC). However, the benefits of RARC over ORC remain unclear. Our objective was to conduct a comparative effectiveness analysis between RARC and ORC using data from the National Cancer Data Base.

MATERIALS AND METHODS

Within the National Cancer Data Base, we identified patients with localized muscle-invasive bladder cancer who underwent RC between 2010 and 2013. Patients were stratified according to surgical approach: ORC vs. RARC. Intraoperative endpoints included: the presence of positive surgical margins, the performance of a pelvic lymph node dissection, and number of lymph nodes (LN) removed. Postoperative endpoints included: length of stay (LOS), 30- and 90-day postoperative mortality (POM) rates, 30-day readmission rate, and overall survival (OS). To minimize selection bias, observed differences in baseline characteristics between RARC vs. ORC patients were controlled for using weighted propensity scores. Binary endpoints and OS were assessed using propensity score-adjusted logistic and Cox regression analyses, respectively. POM was assessed using propensity score weighted Kaplan-Meier survival estimates at 30 and 90 days after RC.

RESULTS

Of 9,561 patients who underwent RC, 2,048 (21.4%) and 7,513 (78.6%) underwent RARC and ORC, respectively. The use of RARC increased over time, from 16.7% in 2010 to 25.3% in 2013. With regard to intraoperative outcomes, RARC was associated with equivalent rates of positive surgical margins (9.3% vs. 10.7%, odds ratio [OR] = 0.86, 95% CI: 0.72-1.03; P = 0.10), higher rates of pelvic lymph node dissection (96.4% vs. 92.0%, OR = 2.30, 95% CI: 1.67-3.16; P<0.001), higher median LN count (17 vs. 12, P<0.001), higher rates of LN count above the median (56.8% vs. 40.4%, OR = 1.94, 95% CI: 1.55-2.42, P<0.001). With regard to postoperative outcomes, receipt of RARC was associated with a shorter median LOS (7 vs. 8, P<0.001), and lower rates of pLOS (45.0% vs. 54.8%, OR = 0.68, 95% CI: 0.58-0.79; P<0.001). The 30- and 90-day POM rates were 2.8%, 6.7% for ORC, and 1.4%, 4.8% for RARC, respectively (hazard ratio [HR] = 0.48, 95% CI: 0.29-0.80, P = 0.005 and HR = 0.71, 95% CI: 0.54-0.93; P = 0.014). Finally, with a mean follow-up of 26.9 months, on IPTW-adjusted Cox regression analysis, RARC vs. ORC was associated with a benefit in OS (HR = 0.79, 95% CI: 0.71-0.88; P<0.001).

CONCLUSIONS

Our large contemporary study found an increased adoption of RARC between 2010 and 2013, with more than 1 out of 4 patients undergoing RARC by the end of the study period. We found that RARC was associated with higher LN counts, shorter LOS, and lower POM. Our results allude to potential benefits of RARC while we wait for more definitive answers from randomized trials.