Kidney Week

Abstract: SA-PO121

GFR Estimation Using β2-Microglobulin and β-Trace Protein in Adults With Solid Tumors: A Prospective Cross-Sectional Study

Session Information

• Onconephrology: Clinical and Research Advances - II
  November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
  Abstract Time: 10:00 AM - 12:00 PM

Category: Onconephrology

• 1600 Onconephrology

Authors

• Costa e Silva, Veronica Torres, Universidade de Sao Paulo Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, São Paulo, Brazil

Veronica Torres Costa e Silva,

• Gil, Luiz Antonio, Universidade de Sao Paulo, Sao Paulo, São Paulo, Brazil

Luiz Antonio Gil,

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

Lesley Ann Inker,

• Caires, Renato Antunes, Universidade de Sao Paulo Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, São Paulo, Brazil

Renato Antunes Caires,

• Costalonga, Elerson, Universidade de Sao Paulo Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, São Paulo, Brazil

Elerson Costalonga,

• Coura-Filho, George Barberio, Universidade de Sao Paulo Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, São Paulo, Brazil

George Barberio Coura-Filho,

• Castro, Gilberto, Universidade de Sao Paulo Instituto do Cancer do Estado de Sao Paulo, Sao Paulo, São Paulo, Brazil

Gilberto Castro,

• Levey, Andrew S., Tufts Medical Center, Boston, Massachusetts, United States

Andrew S. Levey,

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

Emmanuel A. Burdmann,

Background

We previously showed that estimated glomerular filtration rate (eGFR) based on serum creatinine (Scr) and cystatin C (Scys)(eGFRcr-cys) is more accurate than equations based on Scr (eGFRcr) or Scys (eGFRcys) in solid tumor patients in Brazil (Onco-GFR Study). β_2-microglobulin (B2M), and β-trace protein (BTP) are filtration markers (FM) that can further improve the accuracy of GFR estimation when used in multi-marker panels with Scr and Scys, but have not been assessed in patients with cancer. The aim of this study is to evaluate the performance of the CKD-EPI equations without race including B2M and/or BTP with creatinine in the Onco-GFR Study.

Methods

Measured GFR (mGFR) was determined using the plasma clearance of ⁵¹Cr-EDTA. Assays for FM were performed at the University of Minnesota.

Results

A group of 1,200 patients with active cancer but mostly (85%) not yet treated were recruited between April 2015 and September 2017 and included for analysis. Patients were 58.8±13.2 years, 50.8% male. Mean (SD) mGFR was 78.5±21.7 ml/min/1.73 m². Mean (SD) serum B2M and BTP were 2.32 (1.05) and 0.72 (0.35) mg/L, respectively. eGFRcr-B2M and eGFRcr-BTP had similar accuracy (similar 1-P₃₀) compared to eGFRcr-cys, whereas the three-marker panels (eGFRcr-cys-B2M and eGFRcr-cys-BTP) and the four-marker panel (eGFRcr-cys-B2M-BTP) were more accurate (smaller 1-P₃₀) than eGFRcr-cys (Table).

Conclusion

B2M and BTP can improve the accuracy of GFR estimation and may be useful as a confirmatory test in patients with solid tumors, either by inclusion in multi-marker panel with Scr and Scys, or by substituting for Scys in combination with Scr. This may be of particular importance for use of B2M, which may be more available than Scys in cancer centers. We suggest further evaluation of B2M and BTP in other cancer centers.