Objectives: The purpose of this study was to perform a comprehensive assessment of long-term renal function in patients treated at our institution for synchronous bilateral Wilms tumor (BWT) and to determine the optimal method for estimating glomerular filtration rate (eGFR).
Methods: Surgical approach, adjuvant therapy, and pathology reports were reviewed for patients with at least six months follow-up from definitive surgery. eGFRs, as assessed by the Schwartz and Chronic Kidney Disease in Children (CKiD) formulas, were compared to measured GFR (mGFR) determined by 99mTc-DTPA scanning. Urine studies, including microalbumin, β-microglobulin, and FENa were also reviewed.
Results: Forty-two patients were identified. Of 36 living patients, 28 (77.8%) had greater than 6months follow-up, with a median overall follow-up of 5.2years (range: 1.4-13.4). The median mGFR was 97mL/min/1.73m2, while the median eGFRSchwartz and eGFRCKiD were 103.3mL/min/1.73m2 and 79.7mL/min/1.73m2, respectively, (p=0.13 and p=0.75, compared to mGFR). Eleven (39.3%) patients had at least one abnormal urine study (microalbumin >30μg/g creatinine, n=3; β-2 microglobulin >133μg/g creatinine, n=9; FENa>1%, n=4).
Conclusions: In our series, few patients had an abnormally low GFR. Neither method for estimating GFR gave a significantly different result from measured GFR, suggesting that the Schwartz equation is adequate, although specific urine tests may be more sensitive for detecting subtle renal dysfunction.
Level of evidence: Level IV - retrospective case series with no comparison group.
Keywords: Bilateral Wilms tumor; Nephron-sparing surgery; Renal function.
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