Kidney Week

Abstract: FR-OR009

Discrepancy in Glomerular Filtration Rate in Patients with Cancer

Session Information

• Advancing Onconephrology Precision: Biomarkers, Therapeutic Targets, and Patient Outcomes
  October 23, 2026 | Location: Room 401, Convention Center
  Abstract Time: 05:50 PM - 06:00 PM

Category: Onconephrology

• 1600 Onconephrology

Authors

• Costa e Silva, Veronica Torres, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Veronica Torres Costa e Silva, MD, PhD

• Inker, Lesley, Tufts Medical Center, Boston, Massachusetts, United States

Lesley Inker, MD, MS, FASN

• Caires, Renato A., Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Renato A. Caires, MD

• Kassar, Liliana M L, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Liliana M L Kassar, MD

• Mattedi, Francisco Zanotelli, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Francisco Zanotelli Mattedi, MD

• Sise, Meghan E., Massachusetts General Hospital, Boston, Massachusetts, United States

Meghan E. Sise, MD, MS

• Ribeiro, Rayra Gomes, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Rayra Gomes Ribeiro, MD

• Sapienza, Marcelo Tatit, Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Marcelo Tatit Sapienza, MD, PhD

• Burdmann, Emmanuel A., Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil

Emmanuel A. Burdmann, MD, PhD

Background

Differences between estimated glomerular filtration rate (eGFR) and measured GFR (mGFR) are well recognized in the overall population. GFR discrepancies have not been well described in patients with cancer, although they impact chemotherapy eligibility and dose adjustment.

Methods

This cross-sectional analysis evaluated a prospective cohort of patients with solid tumors in treatment at a Brazilian tertiary cancer center. eGFR was calculated from serum creatinine (Scr) concentration alone (eGFRcr) and with cystatin C (Scys) (eGFRcrcys) using the 2021 CKD-EPI equations. Scr and Scys were measured before treatment initiation using certified reference materials on the same day as the mGFR, which was determined by the plasma clearance of ⁵¹Cr-EDTA. mGFR and eGFR were expressed in ml/min/1.73 m². Chronic kidney disease (CKD) was defined and staged according to the KDIGO guidelines.

Results

A group of 1,200 patients with active cancer was recruited between April 2015 and September 2017 and included for analysis. Patients were 58.8±13.2 years, 50.8% male. The most common cancer sites were breast (22.6%), prostate (19.8%), and gastrointestinal (13.4%); metastasis was observed in 14.8% of patients. Mean (SD) mGFR was 78.5±21.7 ml/min/1.73 m². CKD prevalence based on mGFR, eGFRcr, and eGFRcrcys was 18.9, 10.2, and 15.7%, respectively. Among those with mGFR of 45 to 59, 72.1% had eGFRcr greater than 60; among those with mGFR < 45, 52.5% had eGFRcr greater than 45. eGFRcrcys improved GFR discrepancy, but concordance remained poor.

Conclusion

eGFRcr and eGFRcrcys largely underestimated the prevalence of CKD stages in this cohort of patients with solid tumors, particularly the thresholds requiring decisions about drug eligibility and dose adjustment. These results suggest that errors in GFR estimation may contribute to exceeding toxicity in patients with cancer receiving anticancer therapy and call for an urgent need to incorporate more robust instruments to assess GFR in clinical practice.

Funding

• Government Support – Non-U.S.