GFR Evaluation Among Patients with Cancer: Insights and Clinical Implications

Accurately assessing the glomerular filtration rate (GFR) is critical in patients with cancer for acute kidney injury diagnosis, chemotherapy selection, drug dosing, and clinical trial eligibility. Yet, traditional equations such as Cockcroft-Gault and MDRD fail due to multiple physiological changes specific to this vulnerable population. Cancer-related sarcopenia, creatinine secretion blockade, and total body volume fluctuations may lead to inaccurate GFR estimations. This ultimately leads to undertreatment of underlying malignancy, overdosing of nephrotoxic therapies with adverse effects, and excluding patients from clinical trials unnecessarily. The 2024 KDIGO guidelines as well as the American Society of Onconephrology position statement recommend the use of combined GFR equation such as CKD-EPI 2021 that utilizes both cystatin C and creatinine to improve GFR estimation accuracy. Direct GFR measurement via exogenous filtration markers should be pursued in high-risk patients when precise values are warranted. This review highlights current challenges associated with GFR evaluation in patients with cancer and outlines clinical implications as well as recent recommendations for optimal clinical practice.