Investigating racial inequities of circulating tumor DNA (ctDNA) use in patients with non-small cell lung cancer: A real world analysis.

Authors

null

Angelica D'Aiello

Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY

Angelica D'Aiello , Hiba Narvel , Ayse Ece Cali Daylan , Eleftheria Atalla , Sindhu Vikash , Sheila Solomon , Haiying Cheng , Jianyou Liu , Xiaonan Xue , Balazs Halmos

Organizations

Montefiore Medical Center, Albert Einstein College of Medicine, Bronx, NY, Albert Einstein College Of Medicine, Jacobi Medical Center, Bronx, NY, Jacobi Medical Center, Bronx, NY, Albert Einstein College of Medicine, Jacobi Medical Center, Bronx, NY, Guardant Health, Bronx, NY, Albert Einstein College of Medicine, Bronx, NY, Montefiore Medical Center and Albert Einstein College of Medicine, Bronx, NY

Research Funding

No funding received
None.

Background: The use of ctDNA has emerged as an invaluable adjunct to tissue-based molecular testing, though it remains unclear if racial inequities associated with ctDNA implementation exist. We sought to assess disparities in frequency of actionable alterations detected and utilization of those results for treatment decisions in a diverse urban population of NSCLC patients. Methods: We performed a retrospective study of NSCLC patients who received Guardant ctDNA testing from 11/2015-10/2022. Kaplan Meier curves with log-rank tests were used to assess time-to-treatment initiation or treatment change from date of ctDNA collection among race/ethnicity subgroups (Hispanic, Black, White). Univariate associations between race/ethnicity subgroups, NCCN actionable mutation detection, and variant allele frequency, were assessed using Chi-Square and Kruskal-Wallis tests for categorical and continuous variables, respectively. Results: We identified 258 subjects. The race/ethnicity distribution in order of prevalence was Hispanic (33.0%, n = 85), Black (32.6%, n = 84), White (24.8%, n = 64), and Asian/other/unknown (9.7%, n = 25). Median turnaround time for ctDNA result was 8 days (range 2-24 days) from collection date. Median time-to-treatment initiation or change was 25 days for the combined cohort, and 24 days for patients with treatment naïve metastatic disease. Time-to-treatment initiation or change was similar among race/ethnicity subgroups in the combined cohort, as well as those specifically with metastatic disease not yet initiated on treatment at time of ctDNA testing (p = 0.52 and p = 0.43, respectively). Similar proportions of all race/ethnicity subgroups had an NCCN actionable mutation detected (p = 0.92) and similar variant allele frequencies (p = 0.68). An NCCN actionable mutation was detected in 35.3% (n = 91) of patients, the most common being EGFR (n = 53) and KRAS G12C (n = 17). CtDNA results helped avoid the need for repeat tissue biopsy in 25.6% (n = 66) of patients. Of the 68% (n = 175) of patients with paired tissue and liquid biopsies, 24.0% (n = 42) of patients had discordant results, and 8.6% (n = 15) had additional alterations detected on liquid biopsy. Conclusions: In our diverse cohort, we observed a similarly high detection rate of actionable mutations and early time-to-treatment based on ctDNA results across all race/ethnicity subgroups. In addition, ctDNA helped avoid need for repeat tissue biopsy in 25% of patients and yielded additional alterations not detected on tissue in nearly 10% of patients with discordant results. Our findings suggest that broad based molecular testing utilizing ctDNA is not only feasible, but also that it enables faster time-to-treatment in a racially diverse urban population. Continued efforts are necessary to ensure timely molecular testing among all patients, and to identify any racial inequities that may exist.

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Abstract Details

Meeting

2023 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Lung Cancer—Non-Small Cell Metastatic

Track

Lung Cancer

Sub Track

Metastatic Non–Small Cell Lung Cancer

Citation

J Clin Oncol 41, 2023 (suppl 16; abstr 9133)

DOI

10.1200/JCO.2023.41.16_suppl.9133

Abstract #

9133

Poster Bd #

121

Abstract Disclosures