Impact of Host Factors on Robotic Partial Nephrectomy Outcomes: Comprehensive Systematic Review and Meta-Analysis

Abstract

Purpose: Host factors (tumor size/complexity, patient comorbidities) impact outcomes of robotic partial nephrectomy. We report a comprehensive systematic review and meta-analysis to critically evaluate the impact of host factors on operative, perioperative, functional, oncologic and survival outcomes of robotic partial nephrectomy.

Materials and methods: All full text English language publications on robotic partial nephrectomy comparing host factors were evaluated. We followed the PRISMA (Preferred Reporting Items for Systematic Review and Meta-Analyses) statement and AHRQ (Agency for Healthcare Research and Quality) guidelines to evaluate PubMed®, Scopus® and Web of Science® databases (January 1, 2000 to June 31, 2017). Weighted mean difference and odds ratio were used to compare continuous and dichotomous variables, respectively. Sensitivity analyses were performed as needed. To condense the sheer volume of analyses the data are presented using novel summary forest plots. This study is registered with PROSPERO, number CRD42017062712.

Results: Our meta-analysis evaluated 41 studies including 10,506 patients. In terms of tumor factors, compared to patients with complex tumors, those with noncomplex tumors had lesser operating room time (WMD -44.95, p=0.003), estimated blood loss (WMD -160, p <0.003), warm ischemia time (WMD -8.56, p ≤0.00001) and postoperative complications (OR 0.42, p=0.01). Tumors larger than 4 cm were associated with greater operating room time (WMD 30.11, p ≤0.00001), estimated blood loss (WMD 39.26; 95% CI 28.77, 49.74; p ≤0.00001), warm ischemia time (WMD 5.17, p ≤0.00001), transfusions (OR 3.15, p=0.003), postoperative complications (OR 1.88, p=0.004) and length of stay (WMD 0.56, p=0.0004). Hilar tumors involved greater estimated blood loss (WMD 51.34, p=0.03), warm ischemia time (WMD 8.17, p ≤0.00001) and conversion to open partial nephrectomy (OR 14.14, p=0.006). Tumor location, anterior vs posterior, did not impact robotic partial nephrectomy outcomes. As for patient factors, older patients (70 years or older) trended nonsignificantly toward greater percentage decrease of estimated glomerular filtration rate and overall mortality. The abnormal body mass index cohort reported greater operating room time (WMD 13.47, p <0.001), estimated blood loss (WMD 45.44, p <0.0001) and postoperative complications (OR 1.48, p=0.03). The chronic kidney disease cohort had a lesser reduction in postoperative percentage estimated glomerular filtration rate (WMD 7.16; 95% CI 2.74, 11.59; p=0.002) and increased postoperative complications (OR 2.05; 95% CI 1.47, 2.85).

Conclusions: Robotic partial nephrectomy outcomes are impacted by host factors, including tumor and patient characteristics. Awareness of this increased risk and its mitigation with expert patient selection are important for excellent robotic partial nephrectomy outcomes. Our meta-analysis provides comprehensive, objective, summary data of 10,506 patients, detailing discrete outcomes for discrete host factors to better inform urologists and patients considering robotic partial nephrectomy.

Keywords: kidney neoplasms; laparoscopy; nephrectomy; organ sparing treatments; robotics.