Outcomes of Laparoscopic and Robotic Partial Nephrectomy for Large (>4 Cm) Kidney Tumors: Systematic Review and Meta-Analysis

Purpose: The aim of this study was to assess the outcomes of minimally invasive (laparoscopic and robotic) partial nephrectomy (MIPN) for large renal masses. Materials and Methods: A systematic literature review was performed up to September 2016 using multiple search engines to identify studies comparing MIPN for tumors larger than 4 cm (>cT1a) with MIPN for tumors smaller than 4 cm (cT1a). The preferred reporting items for systematic reviews and meta-analyses (PRISMA) criteria were used for article selection. Baseline demographics and surgical, functional, and oncological parameters were extracted from the included studies whenever available. An overall analysis including all studies was performed, then sensitivity analyses were performed for studies on laparoscopic partial nephrectomy (PN) only, and, finally, for studies on robotic PN only. Results: Overall, 13 case-control studies comparing the outcomes of PN in tumors <4 cm (n = 4441) with those of PN for tumors >4 cm (n = 1024) were included. Warm ischemia time was shorter for the <4 cm group [weighted mean difference (WMD) 3.75 min; 95% confidence interval (CI) −6.4 to −0.7; p = 0.01] and the odds of perioperative complications was lower [odds ratio (OR) 0.62; 95% CI 0.5–0.8; p < 0.001]. There were no significant differences in terms of postoperative estimated glomerular filtration rate (WMD 4.2 ml/min; 95% CI 0.45–8.97; p = 0.08), as well as onset of postoperative chronic kidney disease (risk ratio 0.71; 95% CI 0.48–1.04; p = 0.08). In addition, no difference was found in the likelihood of positive surgical margins (OR 0.74; 95% CI 0.43–1.28; p = 0.29). Conclusions: MIPN represents a viable treatment option for renal masses larger than 4 cm (higher than cT1a) as it offers good functional outcomes, without increased risk of positive surgical margins. An increased rate of complications should be taken into account when approaching these tumors.