Removing race as a variable in estimated glomerular filtration rate (eGFR) equations could lead to undertreatment of Black patients with cancer, according to research published in The Lancet Oncology.

The researchers noted that accurately assessing a patient’s kidney function is necessary for determining treatment eligibility and dosage in the cancer setting. eGFR equations are widely used for kidney function assessment, and use of the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) equation is recommended by the Kidney Disease Improving Global Outcomes (KDIGO) group.

The CKD-EPI is designed to adjust for race, and it increases eGFR by 15.9% for Black patients. This adjustment reflects “the higher measured GFR observed in Black versus non-Black patients of a similar age, the same sex, and similar serum creatinine concentration,” according to the researchers.

There is, however, a debate on whether race should be used as an adjusting variable in eGFR calculations.

The researchers therefore conducted a study to evaluate the effects of removing or including race data in eGFR calculations. Using data from National Cancer Institute phase 1 trials, the researchers compared results with 3 eGFR equations: the CDK-EPI, the CDK-EPI without race, and the Cockcroft-Gault equation.

The study included data from 3931 cancer patients, 340 (9%) of whom were Black.

The researchers found that results for Black patients were similar with the Cockcroft-Gault equation and the CDK-EPI without race.

However, the CKD-EPI without race was more likely than the standard CKD-EPI to recommend dose reductions for Black patients or deem them ineligible for certain therapies. Specifically, up to 5% of patients had conflicting recommendations for drug eligibility, and up to 18% had conflicting recommendations for drug dosing.

The number of patients who were deemed ineligible for therapy when CDK-EPI without race was used instead of the standard CKD-EPI increased by 72% for cisplatin, 120% for pemetrexed, and 67% for bendamustine.

The number of patients for whom dose adjustment was recommended when CDK-EPI without race was used instead of CKD-EPI increased by 150% for capecitabine, 150% for etoposide, 67% for topotecan, 61% for fludarabine, and 163% for bleomycin.

“[R]emoval of race from the CKD-EPI equation results in estimates of GFR that will change care for Black patients with cancer by excluding more patients from receiving full doses of potentially life-saving therapy, which could adversely affect survival outcomes,” the researchers wrote.

“Although guidance on implementation of new, race-agnostic methods of kidney function assessment is forthcoming, the timeline for widespread clinical implementation is unclear, and omission of race from the CKD-EPI equation in the interim could negatively affect care for Black patients with cancer,” they concluded.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures. 

Reference

Casal MA, Ivy SP, Beumer JH, Nolin TD. Effect of removing race from glomerular filtration rate-estimating equations on anticancer drug dosing and eligibility: A retrospective analysis of National Cancer Institute phase 1 clinical trial participants. Lancet Oncol. Published online August 13, 2021. doi:10.1016/S1470-2045(21)00377-6

This article originally appeared on Cancer Therapy Advisor