Chronic Kidney Disease in Children With Unilateral Renal Tumor

Purpose: In patients who have undergone nephrectomy lower stage chronic kidney disease may develop, which is an independent risk factor for cardiovascular disease and overall mortality. We investigated whether the prevalence of lower stage chronic kidney disease is related to the amount of renal parenchyma excised in children with unilateral renal tumor. Materials and Methods: A total of 15 patients treated with nephrectomy and 10 treated with nephron sparing surgery were enrolled at a single academic center. The Kidney Disease Outcomes Quality Initiative guidelines were used to classify patients by chronic kidney disease stage based on estimated glomerular filtration rate values. The Modification of Diet in Renal Disease study equation and Schwartz equation were used in patients older and younger than 17 years, respectively. Results: At a mean followup of more than 12 years 8 patients who had undergone nephrectomy and 1 treated with bilateral nephron sparing surgery presented with stage II chronic kidney disease (estimated glomerular filtration rate 60 to 89 ml/min/1.73 m(2)). Sequential measurements from diagnosis to 12 to 17 years postoperatively showed that stage II chronic kidney disease in patients who had undergone nephrectomy manifested as a negligible postoperative increase in mean +/- SD estimated glomerular filtration rate (75.7 +/- 25.5 vs 79.4 +/- 3.9 ml/min/1.73 m(2), p = 0.6). Five of the 8 patients presented with stage II chronic kidney disease even before nephrectomy. The other 7 patients who had undergone nephrectomy and those treated with nephron sparing surgery presented with a significant postoperative increase in mean +/- SD estimated glomerular filtration rate (81.1 +/- 24 vs 102.3 +/- 3 ml/min/1.73 m(2), p = 0.02, and 88.7 +/- 2 vs 107.4 +/- 14 ml/min/1.73 m(2), p = 0.005, respectively). Conclusions: A subset of children with unilateral renal tumor presents before and/or after nephrectomy, and not after nephron sparing surgery, with stage II chronic kidney disease, probably due to a reduced renal reserve capacity. Whether patients with preoperative renal dysfunction may benefit from nephron sparing surgery should be studied in a cooperative clinical trial setting.