Laparoscopic Renal Cryoablation Versus Laparoscopic Partial Nephrectomy for the Treatment of Small Renal Masses: A Systematic Review and Meta-analysis of Comparative Studies

Background: For small renal masses (SRMs), open partial nephrectomy represents the therapeutic standard of care, and laparoscopic partial nephrectomy (LPN) has provided encouraging outcomes. Laparoscopic renal cryoablation (LRC) could be regarded as an alternative to surgical excision in selected patients, if perioperative complication rates and oncologic results are comparable. However, the short-and long-term outcomes of LRC versus LPN have not been adequately assessed. This study evaluated the safety and efficacy of LRC compared with LPN in the treatment of SRMs. Materials and Methods: A systematic search of the Medline, Scopus, and CNKI databases and the Cochrane Library was performed up to October 1, 2013. Outcomes of interest assessing the two techniques included demographic and clinical baseline characteristics, surgical and oncological variables, renal function, and complications. Results: Nine eligible trials (555 cases and 642 controls) assessing LRC versus LPN were identified, including two prospective and seven retrospective studies. Patients undergoing LRC were significantly older (weighted mean difference [WMD], 6.48 years; 95% confidence interval [CI], 3.12-9.83; P < .001) and had a higher solitary kidney rate (odds ratio [OR] = 3.76; 95% CI, 2.05-6.92; P < .001). Although LRC was associated with shorter operative time (WMD, -54.28 minutes; 95% CI, -83.79 to -24.78; P < .001), less blood loss (WMD, -111.75 mL; 95% CI, -147.96 to -75.53; P < .001), lower risk of conversion (OR = 0.17; 95% CI, 0.05-0.60; P = .005), and fewer overall complications (OR = 0.53; 95% CI, 0.29-0.98; P = .04), especially the rate of intraoperative complications (OR = 0.20; 95% CI, 0.07-0.58; P = .003) and major complications (OR = 0.45; 95% CI, 0.25-0.81; P = .008), patients having LPN might still benefit from a significantly lower local recurrence rate (OR = 13.03; 95% CI, 4.20-40.39; P < .001) and lower distant metastasis rate (OR = 9.05; 95% CI, 2.31-35.51; P = .002). Conclusions: Compared with LPN, LRC was associated with reliable perioperative safety, comparable renal function, and fewer complications; however, LRC may still result in a higher risk of tumor progression. Therefore, our meta-analysis suggested that LRC was associated with worse oncological outcomes than LPN but that LRC may be indicated in selected patients with significant comorbidity. Because of the inherent limitations of the included studies, further large sample, prospective, multicenter, and long-term follow-up studies are awaited to corroborate these findings.