National comparison of oncologic quality indicators between open and robotic-assisted radical cystectomy.

INTRODUCTION: Despite increased adoption of robotic-assisted radical cystectomy (RARC), no national data have validated its oncologic efficacy compared to the "standard" open radical cystectomy (ORC). Positive surgical margins (PSM) and lymph node (LN) yield during radical cystectomy (RC) have an established relationship with bladder cancer outcomes. Here, we propose these 2 as quality indicators for RC and assess their differences to compare the oncologic efficacy between RARC and ORC.

METHODS: Using the National Cancer Data Base for the years 2010 to 2012, all patients who underwent ORC or RARC were analyzed. Baseline demographic and cancer stage information were compared as well as unadjusted rates of PSM and LN yield. Survival effect of each indicator was assessed. Using propensity score adjustment, rates of PSM and LN yield were compared between RARC and ORC.

RESULTS: A total of 12,036 patients are included who underwent RC, 20% (2,397) of which were performed robotically. Percentage RARC of total RC increased from 16.2% to 23.3% over the 3 study years. Compared to ORC, patients who underwent RARC were no different in age but were more often men (78.4% vs. 73.6%, P<0.001), had less-advanced cancer stage, and were more likely to have received neoadjuvant chemotherapy (20.9% vs. 14.5%, P<0.001). Most RARC procedures were performed at academic medical centers (66.1%). Unadjusted rates of PSM were lower in the RARC group (10.8% vs. 13.2%, P = 0.002) whereas median LN yield was higher in RARC patients (16 [interquartile range 9, 25] vs. 11 [interquartile range 5, 19], P<0.001). After propensity score covariate adjustment, there was no significant difference in PSM rate between RARC and ORC (-1.12% difference, [95% CI:-2.8, 0.32%]. However, RARC was associated with a higher node yield (+3.32 LN, [95% CI: 2.61, 4.03]) than ORC (P<0.001).

CONCLUSION: The RARC is becoming more prevalent. In a national cohort, RARC was performed more often on men, with lower stage cancer, who were more likely to receive neoadjuvant chemotherapy. Controlling for these factors, RARC had comparable PSM rates but slightly higher LN yield than ORC.