A Comparison of Blood Based Testing to Tissue Sampling for the Detection of Mutations in Non Small Cell Lung Cancer
Daniel Lee1, Selina Juarez2, Christine Schammel3, David P. Schammel3, James Stephenson2, William Bolton2, Sharon Ben-Or2.
1University of South Carolina School of Medicine Greenville, Greenville, SC, USA, 2Prisma Health Upstate, Greenville, SC, USA, 3Pathology Associates, Greenville, SC, USA.
Objective: The treatment of Non-small cell lung cancer (NSCLC) has become more sophisticated with the advent of new chemotherapeutic modalities. While these new treatments require detection of genetic mutations within tissue biopsy, there are new detection modalities which detect genetic mutations via cell free DNA in the blood. The goal of this project is to compare these two modalities in a single population in terms of time to obtain results and concordance between blood and tissue samples.
Methods: A retrospective evaluation of the time to get results from blood (CirculogeneŽ) and tissue along with identification of genetic mutations was completed in patients with lung lesions between 4/1/2019 and 6/15/2019.
Results: Overall, 51 patients (22 NSCLC) were included in the study. The average time to report results for the blood tests (6 days) was significantly different than tissue for EGFR (9 days; p=0.001), PD-L1 (9 days; p=0.007), ROS-1 (14 days; p=0.0001) and ALK (14 days; p=0.0001; Table 1). Genetic results between blood and tissue (Table 2) revealed significantly more -/- concordance for EGFR (p=0.004) and PD-L1 (p=0.04), while significant discordant results were observed for PD-L1 (19% + blood/- tissue; 47% - blood/+tissue; p=0.05). Discordant results for EGFR were identical for blood and tissue; however, the sample size was too small to determine significance.
Conclusions: While the report time for Circulogene results are notably quicker than traditional tissue testing, based on PDL1 results, patients may benefit from both tests to determine treatment not withstanding a sampling error in tissue/sensitivity error in blood.
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