Washington University long-term experience with renal cryoablation versus robot-assisted partial nephrectomy, "Beyond the Abstract," by Eric H. Kim, MD

BERKELEY, CA (UroToday.com) - With intermediate to long term experience in both renal cryoablation (CA) and robot-assisted partial nephrectomy (RAPN), we believed our institution’s experience could provide meaningful insight regarding the relative success of CA in the treatment of small renal masses.[1] With preliminary data suggesting no significant differences in perioperative or oncologic outcomes based on CA approach (laparoscopic vs percutaneous), we combined both CA modalities in our analysis.[2]

Our study was limited by significant differences in baseline patient and tumor characteristics between groups. Patients undergoing CA were significantly older and with greater medical comorbidities. Tumors selected for CA were smaller in size and less complex, favoring posterior location as well as exophytic growth. Unfortunately, due to our retrospective design, these selection biases were unavoidable.

Despite the limitations, three important outcomes were noted. First, the perioperative complication rates were nearly identical between the groups (8.6% following CA and 9.4% following RAPN, p=0.75). Multiple logistic regression analysis demonstrated no significant difference in risk for perioperative morbidity between CA and RAPN. Second, renal functional decline after CA was significantly less than after RAPN (-6% change in eGFR following CA and -13% change following RAPN, p < 0.01). Multiple linear regression analysis demonstrated that RAPN, hilar tumor location, and larger tumor size were associated with a significantly greater risk for renal functional loss. Third, 5-year Kaplan-Meier estimated recurrence-free survival was 83% following CA and 100% following RAPN. Multivariate cox proportional hazards analysis demonstrated that endophytic tumor growth and CA were significant predictors of disease recurrence.

In carefully selected patients -— particularly those with small tumors and considerable medical comorbidities -— CA is a safe, nephron-sparing treatment alternative with reasonable oncologic efficacy. Alternatively, in patients who are healthy enough to undergo extirpative surgery and who have more complex tumors, RAPN represents a substantially superior oncologic treatment.


  1. Tanagho YS, Bhayani SB, Kim EH, Figenshau RS. Renal Cryoablation Versus Robot-Assisted Partial Nephrectomy: Washington University Long-Term Experience. J Endourol 2013; 27(12): 1477-1486.
  2. Kim EH, Tanagho YS, Saad NE, et al. Comparison of Laparoscopic and Percutaneous Cryoablation for Treatment of Renal Masses. Urology 2014. In Press.

Written by:
Eric H. Kim, MD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.

Washington University School of Medicine, Division of Urology, 7469 Delmar Blvd., University City, MO USA

Renal cryoablation versus robot-assisted partial nephrectomy: Washington University long-term experience - Abstract

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