Patient-Paired Sample Congruence Between 2 Commercial Liquid Biopsy Tests

Abstract

This cohort study examines the reliability and potential utility of 2 commercially available liquid biopsy assays for reported mutations in cell-free DNA.

Figure 1.. Mutational Landscape Obtained by cfDNA Testing in Metastatic Prostate Cancer Patients

Each column represents 1 patient with 1 or more alterations reported in at least 1 platform. Only alterations in genes purportedly covered by both commercial gene panels were considered. Exome coverage for each gene in the sequencing panel differs between platforms. Congruence among tests was assessed on confirmation of exome coverage with the counterpart platform for each alteration in the study. cfDNA indicates cell-free DNA; G, results using Guardant360 (Guardant Health, Inc); P, results using PlasmaSELECT (Personal Genome Diagnostics, Inc), PSA, prostate-specific antigen.

Figure 2.. Congruence Analysis of cfDNA-Targeted Next-Generation Sequencing in 2 Independent Commercial Platforms

Patients negative for cell-free DNA (cfDNA) alterations in both tests were classified as complete congruence for 0 alterations (9/40 [22.5%]). For congruence analysis, patients who had 1 or more alterations reported, but none was covered by both tests, were excluded and classified as not evaluable for patient-level congruence (6/40 [15%]). The proportion of patients with complete congruence for 1 or more alterations, partial, and no congruence was 3 of 40 (7.5%), 6 of 40 (15%), and 16 of 40 (40%), respectively, among the 2 platforms.