Glomerular filtration rate in children with solid tumors: normative values and a new method for estimation

Area of Science:

• Pediatric Nephrology
• Pediatric Oncology
• Pharmacokinetics

Background:

• Nephrotoxic chemotherapy regimens necessitate accurate glomerular filtration rate (GFR) estimation for pediatric dosing.
• Limited data exists on normal GFR values in pediatric populations, complicating precise medication management.
• Establishing normative GFR data is crucial for optimizing treatment and minimizing renal toxicity in children undergoing chemotherapy.

Purpose of the Study:

• To determine normal glomerular filtration rate (GFR) values in children with nonhematogenous malignancies.
• To develop a practical equation for estimating absolute GFR in pediatric patients.
• To provide essential data for accurate chemotherapy dosing in pediatric oncology.

Main Methods:

• Directly measured GFR using iothalamate infusion methodology in 111 children with nonhematogenous malignancies.
• Exclusion criteria included renal involvement or prior exposure to nephrotoxic agents.
• Statistical analysis to correlate GFR with age, sex, weight, and serum creatinine.

Main Results:

• GFR adjusted for body surface area increases in the first two years of life, then stabilizes at adult levels.
• Mean GFR (mL/min/1.73 m(2)) for males >2 years was 131.3 +/- 22.5 and for females was 126.8 +/- 24.4.
• A validated formula (r(2) =.97) was derived to estimate absolute GFR (mL/min) using weight, age in months, and serum creatinine.

Conclusions:

• Accurate GFR measurement is vital for safe and effective pediatric solid tumor treatment.
• This study establishes normative GFR values for children with nonhematogenous malignancies.
• The developed equation offers a reliable method for estimating absolute GFR, facilitating appropriate chemotherapy dosing.