Blog | Oct. 22, 2019

High tissue biopsy to liquid biopsy concordance with OncoBEAM enhanced digital PCR – Part III

A recent publication summarizes the results of RAS mutation status in colorectal cancer (CRC) from 19 available clinical trials with matched tissue and ctDNA; OncoBEAM technology shines

In Part I of our liquid biopsy concordance series, we summarized seven publications and an internal dataset correlating the RAS mutation status between CRC tissue biopsy and cell-free DNA liquid biopsy. Across 913 patient samples, an overall percent agreement (OPA) of 90.3% was reported, with a positive percent agreement (PPA) of 88.7% and a negative percent agreement (NPA) of 91.8%.

In a recent report by Galvano et al. 2019 (“Detection of RAS mutations in circulating tumor DNA: a new weapon in an old war against colorectal cancer. A systematic review and meta-analysis”) the authors examined 19 clinical trials comparing RAS mutational status via standard tissue biopsy and ctDNA analysis.

A summary of the concordance results between matched CRC tissue and plasma

For the 1,180 patients examined in this meta-analysis, RAS mutational status was determined in ctDNA using one of three methods: NGS in 786 patients, BEAMing in 807 patients, and standard PCR in 217 by PCR. The table below uses data from Table 2 of the paper (available here).

It is clear from this data the superior sensitivity and specificity of the BEAMing technology used in Sysmex Inostics OncoBEAM tests. The summary receiver-operator characteristic (sROC) plots diagrammed as Figure 5 in the paper (available here) graphically illustrates the differences between BEAMing, NGS and PCR.

OncoBEAM technology a clear lead in sensitivity and specificity

The first prospective study has recently been published in Elez et al. 2019 (“Impact of circulating tumor DNA mutant allele fraction on prognosis in RAS-mutant metastatic colorectal cancer”), evaluating the prognostic potential of measuring the prevalence of RAS mutations in plasma and their correlation with overall survival (OS). From a cohort of 37 CRC patients with non-resectable metastatic disease, lower RAS MAF at baseline correlated with significant correlation with longer OS.

A list of the available OncoBEAM tests for CRC and other cancer types by BEAMing are available here and if you have any inquiries please feel free to contact us.

References:

1. Galvano A, Taverna S, and Russo A et al. Detection of RAS mutations in circulating tumor DNA: a new weapon in an old war against colorectal cancer. A systematic review of literature and meta-analysis. Ther Adv Med Oncol. 2019 11:1758835919874653. doi:10.1177/1758835919874653. PubMed Central PMCID: PMC6737868.
2. Elez E, Chianese C and Vivancos A et al. Impact of circulating tumor DNA mutant allele fraction on prognosis in RAS-mutant metastatic colorectal cancer. Mol Oncol. 2019 13(9):1827-1835. doi: 10.1002/1878-0261.12547. PubMed PMID: 31322322.