Dosing of cytotoxic chemotherapy: Impact of renal function estimates on dose

Abstract

Background: Oncology clinicians are now routinely provided with an estimated glomerular ltration rate on pathology reports whenever serum creatinine is requested. The utility of using this for the dose determination of renally excreted drugs compared with other existing methods is needed to inform practice. Patients and methods: Renal function was determined by [Tc99m]DTPA clearance in adult patients presenting for chemotherapy. Renal function was calculated using the 4-variable Modication of Diet in Renal Disease (4v-MDRD), Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), Cockcroft and Gault (CG), Wright and Martin formulae. Doses for renal excreted cytotoxic drugs, including carboplatin, were calculated. Results: The concordance of the renal function estimates according to the CKD classication with measured Tc99mDPTA clearance in 455 adults (median age 64.0 years: range 17-87 years) for the 4v-MDRD, CKD-EPI, CG, Martin and Wright formulae was 47.7%, 56.3%, 46.2%, 56.5% and 60.2%, respectively. Concordance for chemotherapy dose for these formulae was 89.0%, 89.5%, 85.1%, 89.9% and 89.9%, respectively. Concordance for carboplatin dose specically was 66.4%, 71.4%, 64.0%, 73.8% and 73.2%. Conclusion: All bedside formulae provide similar levels of concordance in dosage selection for the renal excreted chemotherapy drugs when compared with the use of a direct measure of renal function. © The Author 2013. Published by Oxford University Press on behalf of the European Society for Medical Oncology All rights reserved.