AUA 2018: On-Clamp vs Off-Clamp Partial Nephrectomy: Propensity Score Matched Comparison of Long Term Functional Outcomes

San Francisco, CA ( The purpose of this study was to compare renal functional outcomes after either off-clamp (Off-C) or on-clamp (On-C) partial nephrectomy (PN) in patients with cT1-2/N0 M0 renal tumors and baseline estimated eGFR >60 ml/min.  This study used a prospective “renal cancer” database of two high volume centers. The database was queried for “cT1-2/N0/M0” tumors and “baseline eGFR>60 mL/min”. Overall 1073 patients met the inclusion criteria, 588 On-C PN and 485 Off-C PN. A 1:3 propensity score-matched (PSM) analysis was employed to minimize the potential selection bias. Regression analysis was used to plot the 2 to 8 yrs probabilities of experiencing eGFR decreases of 0%,< 25% and between 25 and 50% in both PSM cohorts and, therefore, to compare the trends for each of these 3 subgroups. Univariable and multivariable analyses were performed to identify independent predictors of developing a CKD stage 3b. 

In the whole cohort On-C patients were significantly younger (p=0.001), less frequently smokers (p=0.01), with a lower incidence of diabetes (p=0.001) and hypertension (p=0.001), lower ASA scores (p25% in the first 8-yr follow-up (p=0.02). The probability of developing a CKD stage 3b was significantly higher (log rank p=0.006) in the On-C cohort (2, 5 and 8yr risk 0.9%, 5.1% and 12.8% versus 0.6%, 1.2% and 1.2% in the Off-C cohort, respectively. At multivariable Cox regression analysis, eGFR at discharge (HR 0.94; 95% CIs 0.91-0.98, p=0.002) and Off-clamp approach (HR 7.33; 95% CIs 1.8-29.4, p=0.005) were independent predictors of improved renal functional outcomes. 

In conclusion, Off-C PN is associated with a significantly higher probability of maintaining 100% eGFR after surgery compared with On-C PN in patients with cT1-2/N0/MO renal tumors and good baseline renal function. Patients treated with On-C PN had a 7.3 fold increased risk of developing a severe CKD during follow-up.

Presented by: Giuseppe Simone, Rome, Italy

Written by:  Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre @GoldbergHanan at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA
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