Renal function adaptation in children with unilateral renal tumors treated with nephron sparing surgery or nephrectomy

Purpose: We studied the natural history of renal function following removal of different amounts of renal mass in a cohort of children with unilateral renal tumors. Materials and Methods: We compared kidney function and blood pressure before and after surgery in 26 patients with unilateral renal tumors treated with nephrectomy (group 1, 16 patients) or nephron sparing surgery (group 2, 10 patients). Serum creatinine and blood pressure measurements were indexed to age and sex, and expressed as standard deviation scores (SDSs). Values were means +/- SD. Results: Preoperatively, patients in group 1 had no significant differences with respect to serum creatinine SDS and blood pressure SDS compared to patients in group 2. At a mean cross-sectional followup of 72 and 65 months, respectively, patients in group 1 had higher serum creatinine SDS compared to those in group 2 (1.27 +/- 0.69 vs 0.70 +/- 0.49, p = 0.02), as well as higher systolic blood pressure SDS (0.72 +/- 0.74 vs -0.10 +/- 0.92, p = 0.01) and higher diastolic blood pressure SDS (0.87 +/- 0.77 vs 0. 19 +/- 0.62, p = 0.0 1). Serum creatinine SDS and systolic blood pressure SDS had a significant positive correlation (r = 0.44, p = 0.02). A postoperative longitudinal study of all patients showed a progressive increase in serum creatinine SDS with increasing followup time (r(2) 0.49, p = 0.02). The slope of regression line was sustained by a steep increase of serum creatinine SDS in 5 patients in group 1 and 2 patients in group 2. Conclusions: In children with unilateral renal tumors nephron sparing surgery minimizes the decrease in renal function following renal ablative surgery, and may be of benefit in children with a progressive renal function decrease, probably due to a congenitally reduced nephron complement.