Analysis of survival for patients with chronic kidney disease primarily related to renal cancer surgery

Abstract

Objectives: To evaluate predictors of long-term survival for patients with chronic kidney disease primarily due to surgery (CKD-S). Patients with CKD-S have generally good survival that approximates patients who do not have CKD even after renal cancer surgery (RCS), yet there may be heterogeneity within this cohort.

Patients and methods: From 1997 to 2008, 4 246 patients underwent RCS at our centre. The median (interquartile range [IQR]) follow-up was 9.4 (7.3-11.0) years. New baseline glomerular filtration rate (GFR) was defined as highest GFR between nadir and 6 weeks after RCS. We retrospectively evaluated three cohorts: no-CKD (new baseline GFR of ≥60 mL/min/1.73 m² ); CKD-S (new baseline GFR of <60 mL/min/1.73 m² but preoperative GFR of ≥60 mL/min/1.73 m² ); and CKD due to medical aetiologies who then require RCS (CKD-M/S, preoperative and new baseline GFR both <60 mL/min/1.73 m² ). Analysis focused primarily on non-renal cancer-related survival (NRCRS) for the CKD-S cohort. Kaplan-Meier analysis assessed the longitudinal impact of new baseline GFR (45-60 mL/min/1.73 m² vs <45 mL/min/1.73 m² ) and Cox regression evaluated relative impact of preoperative GFR, new baseline GFR, and relevant demographics/comorbidities.

Results: Of the 4 246 patients who underwent RCS, 931 had CKD-S and 1 113 had CKD-M/S, whilst 2 202 had no-CKD even after RCS. Partial/radical nephrectomy (PN/RN) was performed in 54%/46% of the patients, respectively. For CKD-S, 641 patients had a new baseline GFR of 45-60 mL/min/1.73 m² and 290 had a new baseline GFR of <45 mL/min/1.73 m² . Kaplan-Meier analysis showed significantly reduced NRCRS for patients with CKD-S with a GFR of <45 mL/min/1.73 m² compared to those with no-CKD or CKD-S with a GFR of 45-60 mL/min/1.73 m² (both P ≤ 0.004), and competing risk analysis confirmed this (P < 0.001). Age, gender, heart disease, and new baseline GFR were all associated independently with NRCRS for patients with CKD-S (all P ≤ 0.02).

Conclusion: Our data suggest that CKD-S is heterogeneous, and patients with a reduced new baseline GFR have compromised survival, particularly if <45 mL/min/1.73 m² . Our findings may have implications regarding choice of PN/RN in patients at risk of developing CKD-S.

Keywords: chronic kidney disease; kidney cancer; partial nephrectomy; radical nephrectomy; survival.