Background and importance In paediatrics, some carboplatin dosage methods are based on renal clearance. An accurate determination of the glomerular filtration rate (GFR) can be obtained by measuring 51Cr-EDTA clearance but this method is laborious and difficult, especially in children. Hence various formulae have been developed to calculate and estimate GFR.
Aim and objectives The aim of this study was to compare carboplatin doses calculated by the modified Calvert formula with GFR measured by 51Cr-EDTA clearance and GFR estimated with the Schwartz formula in children.
Material and methods All paediatric cancer patients whose GFR was measured by 51Cr-EDTA were included. GFR was also estimated with the Schwartz formula. Demographics of the patients included in the study were collected. To calculate carboplatin dose, the modified Calvert formula was used: dose (mg/m2) = target AUC × (raw GFR (mL/min) + 15 × body surface area (BSA) (m2)). The target AUC chosen was 5 mg/mL/min. Carboplatin doses were calculated with two different values of GFR calculated previously. To test normality, the Kolmogorov–Smirnov test was used. The Student’s t test for paired samples was applied to compare carboplatin mean doses.
Results 33 patients were identified with a median age of 10 years (range 1–17), 63.63% were male. Median weight, height and BSA were 28 kg (range 8–84.4 kg), 137 cm (range 64–182 cm) and 1.04 m2 (range 0.37–2.06 m2), respectively. The mean carboplatin dose calculated with GFR measured by 51Cr-EDTA was 274.28±135.74 mg and with GFR estimated with the Schwartz formula, 364.86±156.59 mg. The mean difference between the two dosing methods was 90.58 mg (p<0.001).
Conclusion and relevance Carboplatin doses calculated with GFR estimated by the Schwartz formula were statistically higher than those measured by 51Cr-EDTA. This variability may be a risk factor leading to inadequate dosing of patients treated with carboplatin. GFR measured with 51-Cr-EDTA is considered the gold standard. Therefore, it should be implemented in all centres where carboplatin is given to paediatric patients.
Conflict of interest No conflict of interest