Systematic Review and Meta-Analysis of Comparative Studies Reporting Perioperative Outcomes of Robot-Assisted Partial Nephrectomy Versus Open Partial Nephrectomy

Background: Robot-assisted partial nephrectomy (RAPN) is increasingly being used for the surgical management of renal masses. The comparison of RAPN with open partial nephrectomy (OPN) has not yet led to a unified conclusion with regard to perioperative outcomes. Purpose: To conduct a systematic review and meta-analysis of the literature on the perioperative outcomes of RAPN compared with OPN. Methods: We searched PubMed and EMBASE through January 31, 2016, to identify randomized controlled trials (RCTs) and observational comparative studies assessing the comparison of the two approaches (RAPN vs OPN). Primary outcomes were intraoperative complication rate and postoperative complication rate (including minor and major). Secondary outcomes were perioperative transfusion rate, positive surgical margin (PSM) rate, operative time (OT), warm ischemia time (WIT), estimated blood loss (EBL), length of hospital stay (LOS), and estimated glomerular filtration rate (eGFR) change. Results: A total of 19 cohort studies with at least 3551 patients (RAPN, 1216; OPN, 2335) were included. Compared with OPN, RAPN had the advantages of (a) lower rates of postoperative complication (risk ratio [RR] = 0.60, 95% confidence interval [CI] = 0.46, 0.78, p = 0.0002), postoperative minor complication (RR = 0.73, 95% CI = 0.56, 0.96, p = 0.02), and postoperative major complication (RR = 0.50, 95% CI = 0.30, 0.84, p = 0.01); (b) lower need for transfusion (RR = 0.64, 95% CI = 0.41, 0.98, p = 0.04); (c) less EBL (weighted mean difference [WMD] = -98.82, 95% CI = -125.64, -72.01, p < 0.00001); and (d) shorter LOS (WMD = -2.64, 95% CI = -3.27, -2.00, p < 0.00001). Sensitivity analyses excluding studies with obvious selection bias based on tumor complexity confirmed all these advantages. RAPN had longer OT (WMD = 18.56, 95% CI = 2.13, 35.00, p = 0.03) and WIT (WMD = 3.65, 95% CI = 0.75, 6.56, p = 0.01) in the primary analyses. Sensitivity analyses, however, showed no differences between RAPN and OPN regarding OT and WIT. Intraoperative complication rate (RR = 0.61, 95% CI = 0.29, 1.27, p = 0.19), PSM rate (RR = 0.87, 95% CI = 0.56, 1.34, p = 0.52), and short-term eGFR change, including absolute eGFR change (WMD = -1.56, 95% CI = -3.41, 0.28, p = 0.10) and percentage eGFR change (WMD = 0.99, 95% CI = -0.52, 2.50), did not differ between the two approaches. Conclusions: Compared with OPN, RAPN appears to have lower morbidity and achieves similar short-term functional outcomes. However, evidence is limited regarding the long-term oncologic outcomes even though the PSM rate is similar between the two groups. Well-designed RCTs with large sample sizes and long-term follow-up are needed to confirm and update the findings of our study.