SUO 2017: Should Partial Nephrectomy Be Considered Elective In Stage 2 Chronic Kidney Disease? Propensity Score Matched Analysis Of Functional And Survival Outcomes After Radical And Partial Nephrectomy

Washington, DC ( Introduction: While partial nephrectomy (PN) is strongly indicated for patients with stage 3-4 chronic kidney disease [(CKD), eGFR<60 ml/min/1.73m2], higher GFRs are thought to be elective. The authors compared renal function and survival outcomes in patients with baseline stage II CKD who underwent PN or radical nephrectomy (RN).

Methods: This was a retrospective analysis of patients with baseline CKD 2 undergoing PN or RN from 1987−2015. Patients were stratified into CKD 2a (GFR 75−89) and CKD 2b (GFR 60−74.9) and analyzed according to the type of surgery. Primary outcome was change in GFR at last follow-up (eGFR). Secondary outcomes included occurrence of GFR<60, GFR<45 and overall survival.
Propensity score matching on subset of patients with all available covariates (n=1163). For a binary treatment indicator of CKD stage (CKD 2a vs. 2b), Matching was performed 1:1 between groups with a logistic regression estimation and a nearest neighbor matching algorithm. Matching was achieved for 1158 patients (579 per cohort) in this subset. Additionally, for a binary treatment indicator of surgical approach (PN vs RN), matching was achieved for 1044 patients (522 per cohort).

Results: 1213 patients analyzed (50.2% CKD 2a, 49.8% were CKD 2b, median follow-up 49 months). Overall rate of development of eGFR<60, <45, and <30 was 47.6%, 15.2%, and 3.4%, respectively. Rate of development of eGFR<60 and <45 at last follow-up was greater for CKD 2b as opposed to CKD 2a (57.8% vs. 39.0%, p<0.001; 20.5% vs. 10.4%, p<0.001;
respectively). After propensity score matching, rates of development of eGFR <60 and <45 at last follow up remained significantly higher for CKD 2b compared to CKD 2a (58.0% vs. 38.9%, p<0.001; 20.6% vs. 10.5%, p<0.001; respectively).On logistic regression for GFR<45, RN (OR 3.68, p=0.001) and CKD 2b (OR 3.3, p=0.002) were predictive. On logistic regression
for all cause mortality, RN (OR 3.76, p=0.005) and eGFR<45 (OR 2.51, p=0.029) were predictive. Similarly, after propensity matching we noted a consistently negative effect for RN compared to PN for development of eGFR <60 (64.8% vs. 35.6%, p<0.001) and eGFR <45 (23.8% vs. 9.0%, p<0.001).

Conclusion: The authors concluded that patients with baseline CKD 2, particularly CKD 2b who undergo RN, are at increased risk of GFR<45 and decreased overall survival. As such, these patients should not be considered purely elective indications for nephron-sparing surgery, and PN should be prioritized if possible.

Presented by: Zachary A. Hamilton, Saint Louis University, MO, USA

Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre, @GoldbergHanan, at the 18th Annual Meeting of the Society of Urologic Oncology, November 29-December 1, 2017 – Washington, DC