Prognostic factors for chronic kidney disease after curative surgery in patients with small renal tumors.

OBJECTIVES: To investigate the incidence and predictive factors associated with newly developed chronic kidney disease (CKD) after curative surgery in patients with small renal tumors.

METHODS: From 1998 to 2005, we retrospectively investigated 225 patients undergoing partial nephrectomy (PN) or radical nephrectomy (RN) for renal tumors, of size <or= 4 cm, with normal contralateral kidney. The glomerular filtration rate (GFR) was calculated using the four-variable modification of diet in renal disease formula. CKD was defined as GFR of < 60 mL/min per 1.73 m(2). Demographic and clinicopathologic parameters were evaluated using Cox proportional hazards model to determine the variables independently associated with the development of postoperative CKD.

RESULTS: A total of 129 (57.3%) and 96 (42.7%) patients were included in the RN and PN groups. A total of 97 patients (43.1%) developed CKD; 86 (66.7%) underwent an RN and 11 (11.5%) underwent a PN. The 2-year probability of absence of CKD with an RN and a PN was 58.3% and 95.7%, respectively (P <.001). Among 20 patients with diabetes, 12 (60.0%) developed CKD: 10 patients underwent an RN and 2, a PN. The 2-year probability of absence of CKD with and without diabetes was 46.5% and 76.4%, respectively (P = .006). The multivariate analysis showed that age (P = .001), type of operation (P <.001), preoperative GFR (P = .001), and diabetes (P = .042) were associated with the development of CKD.

CONCLUSIONS: The results of this study show that nephron-sparing surgery for small renal mass should be attempted to prevent CKD in all eligible patients, especially those with diabetes.