Carboplatin Dosing in Children: Calculation by Different Formulae

Background: Carboplatin dosing in children is based on renal function and there exists a wealth of formulae available for calculating the body surface area (BSA), the glomerular filtration rate (GFR), and the carboplatin dose. Patients and Methods: A fictitious group of children with different ages and body builds was 'constructed'. For comparison of formulae, bias and precision were assessed. Results: BSA calculations according to DuBois-DuBois, Gehan-George, Mosteller, and Boyd showed good agreement. GFR calculations according to the weight-based Cole formula and the Leger formula gave comparable results. Regarding GFR in young children, the weight- and creatinine-based Cole and the Schwartz formula showed clear differences. Again, carboplatin dose calculations according to Marina, Newell, and Chatelut are comparable. Moreover, the precision of the creatinine measurement has a clear influence on the result of the dose calculation. Conclusions: The choice of the GFR formula is more important for the carboplatin dose calculation compared to the BSA or dose equation. GFR calculations in children show marked, age-dependent variations. A sequence of multiple calculation steps (especially for the Schwartz and Marina formulae) may lead to considerable uncertainty and proneness to error in the clinical routine. In high-risk patients, GFR should be measured precisely and complemented by therapeutic drug monitoring.