Evaluation of carboplatin dosage based on 4-variable modification of diet in renal disease equation

Traditionally, carboplatin dosage is based on the Calvert formula. Glomerular filtration rate (GFR) and creatinine clearance (CrCl) are often used interchangeably in this formula. The modification of diet in renal disease (MDRD) equation is now routinely available to estimate GFR (eGFR). We performed a retrospective analysis of carboplatin dosage in our institute. Calvert formula derived carboplatin dose using eGFR calculated from the MDRD equation was compared to estimated CrCl from the Cockcroft-Gault and Jelliffe equations. Ninety-two carboplatin treatment episodes were recorded. eGFR and CrCl correlated reasonably well with a correlation coefficient (r) of 0.88. The correlation was weakest at lower levels of serum creatinine. Correcting eGFR for body surface area resulted in a tighter correlation (r = 0.94). The MDRD derived eGFR is readily available and may prove very useful in calculating carboplatin dosage for patients with impaired renal function.