GFR Measurement and Chemotherapy Dosing in Patients with Kidney Disease and Cancer

Chemotherapeutic agents require precise dosing to ensure optimal efficacy and minimize complications. For those agents which are removed from the body by the kidney, accurate knowledge of glomerular filtration rate (GFR) is critical. In addition, GFR needs to be determined rapidly, easily and, if possible, with little additional cost. The ability to easily measure GFR also allows for rapid detection of nephrotoxicity. Current methodologies include direct clearance measurement of an indicator substance or estimation of creatinine clearance or GFR through regression equations that use a serum marker such as creatinine or cystatin C. These methodologies all have shortfalls and limitations some of which are specific to the cancer patient. Newer methodologies that directly measure GFR are in clinical trials and offer the ability to rapidly and non-invasively provide accurate estimates of drug clearance as well as detection of nephrotoxicity. These methods offer the opportunity to refine drug dosing and improve outcomes.