Kidney function assessment for eligibility in clinical cancer trials - Data from the European Organisation for Research and Treatment of Cancer

Purpose: There is no consensus on how to estimate kidney function for the assessment of eligibility in clinical cancer trials.

Patients and methods: We recalculated the creatinine clearance (CrCl)/glomerular filtration rate (GFR) at baseline in a total of 1768 patients enrolled in twelve clinical trials using the Cockcroft-Gault (CG), Modification of Diet in Renal Disease (MDRD), 2021 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI 2021) and European Kidney Function Consortium (EKFC) formulas. Patients were classified as having renal impairment (RI; CrCl/GFR <60 mL/min) or no renal impairment (NRI; CrCl/GFR ≥60 mL/min) with each of the four formulas, respectively. Furthermore, we analyzed the number of adverse events (AE) per month under study treatment using measures of central tendency, variability and regression models.

Results: Using CG, EKFC, MDRD and CKD-EPI 2021, 152 (8 %), 140 (8 %), 110 (6 %), and 61 (4 %) patients had RI respectively. Indeed, 47 (3 %) patients had RI using all 4 formulas, while 158 (9 %) had RI by at least one but not all four methods. CG showed the broadest variability and inconsistencies with other methods. All calculation methods performed similarly for excluding patients at risk of severe AE. EKFC demonstrated superior predictive ability for excluding patients at risk of renal and urinary tract AE.

Conclusion: This post hoc analysis highlights the importance of choosing accurate and representative methods for kidney function estimation in clinical cancer trials. CG should be replaced by newer methods. While CKD-EPI 2021 may maximize trial accrual, EKFC should be considered for treatment affecting kidney function.