Nephron Sparing Treatment (NEST) for Small Renal Masses: A Feasibility Cohort-embedded Randomised Controlled Trial Comparing Percutaneous Cryoablation and Robot-assisted Partial Nephrectomy
Joana B. Neves, Hannah Warren, Joseph Santiapillai, Nicola Rode, David J. Cullen, Menelaos Pavlou, Miles Walkden, Prasad Patki, Ravi Barod, Faiz Mumtaz, Michael Aitchison, Steven Bandula, Elena Pizzo, Veronica Ranieri, Norman Williams, William H. Wildgoose, Kurinchi Selvan Gurusamy, Mark Emberton, Axel Bex, Maxine Tran
Abstract
There is a paucity of high-level evidence on small renal mass (SRM) management, as previous classical randomised controlled trials (RCTs) failed to meet accrual targets. Our objective was to assess the feasibility of recruitment to a cohort-embedded RCT comparing cryoablation (CRA) to robotic partial nephrectomy (RPN). A total of 200 participants were recruited to the cohort, of whom 50 were enrolled in the RCT. In the RCA intervention arm, 84% consented (95% confidence interval [CI] 64–95%) and 76% (95% CI 55–91%) received CRA; 100% (95% CI 86–100%) of the control arm underwent RPN. The retention rate was 90% (95% CI 79–96%) at 6 mo. In the RPN group 2/25 (8%) were converted intra-operative to radical nephrectomy. Postoperative complications (Clavien-Dindo grade 1–2) occurred in 12% of the CRA group and 29% of the RPN group. The median length of hospital stay was shorter for CRA (1 vs 2 d; p = 0.019). At 6 mo, the mean change in renal function was −5.0 ml/min/1.73 m2 after CRA and −5.8 ml/min/1.73 m2 after RPN. This study demonstrates the feasibility of a cohort-embedded RCT comparing CRA and RPN. These data can be used to inform multicentre trials on SRM management. We assessed whether patients with a small kidney tumour would consent to a trial comparing two different treatments: cryoablation (passing small needles through the skin to freeze the kidney tumour) and surgery to remove part of the kidney. We found that most patients agreed and a full trial would therefore be feasible.