Utilization of circulating tumor DNA (ctDNA) testing by race and ethnicity in more than 135,000 patients

• Published in: Journal of clinical oncology Vol. 42; no. 16_suppl; p. e13702
• Main Authors: Davis, Andrew A., Bucheit, Leslie A, Zhang, Nicole, Pretz, Christopher, Strickler, John H, Chachoua, Abraham, Wise, David R, Wong, Kwok-Kin, Aviki, Emeline Mariam, Zhang, Tian, Qin, Qian, Clemens, Keelia M.
• Format: Journal Article
• Language: English
• Published: 01.06.2024
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/JCO.2024.42.16_suppl.e13702

e13702 Background: Studies have shown low rates of tumor genomic profiling in the metastatic population and disparities in cancer care have been observed across races, ethnicities, and ages. We aimed to better understand how ctDNA is being utilized across race, ethnicity, and age in common cancer types using a real-world (RWE) clinicogenomic database. Methods: GuardantINFORM is an RWE database that aggregates de-identified records from ctDNA testing (Guardant360), and aggregated payer claims from which race, ethnicity, age, cancer type and setting (academic/community) were extracted from 2021-2023 using the patients’ first test. Common cancers with biomarker/targeted therapy opportunities were included. Rates of ctDNA testing by race were assessed for non-Hispanic (NH) White, Black, and Asian/pacific islander (PI) and separately for Hispanic ethnicity. ctDNA testing rates were compared to recent CDC Wonder incidence using previously published methods (PMID: 36658153) and to tissue-based testing rates (PMID: 33106634) using t-test and Fisher’s Exact Test (significance: p < 0.05). Results: There were no significant differences in sex, setting (academic/community), or age ( > 65, 50-65 years) for each group compared to the overall cohort (p > 0.2). ctDNA testing occurred most frequently in NH White (71.5%) followed by NH Black (12.1%), Hispanic (9.1%), and NH Asian/PI (4.7%); rates were comparable to published tissue-based rates (White: 76%, Black: 7%, Asian: 6%, N/A for Hispanic; p = 0.97). Controlling for incidence, ctDNA testing rates were significantly less-than-expected for 75% (6/8) of cancers in NH White, 37.5% (3/8) of cancers in both NH Black and Asian/PI, and 100% (8/8) of cancers in the Hispanic cohort (Table 1). Conclusions: In this large clinicogenomic database, Black and Asian patients had higher than expected rates of ctDNA testing, while Hispanic patients had lower rates. While the representation of Black patients is encouraging, ongoing efforts are needed to improve availability and frequency of testing, particularly for Hispanic patients. [Table: see text]