Clinical Practice Use of Liquid Biopsy to Identify RAS/BRAF Mutations in Patients with Metastatic Colorectal Cancer (mCRC): A Single Institution Experience

Abstract

Tumor heterogeneity represents a possible cause of error in detecting predictive genetic alterations on tumor tissue and can be overcome by testing alterations in circulating tumor DNA (ctDNA) using liquid biopsy. We assessed 72 consecutive patients with a diagnosis of metastatic colorectal cancer (mCRC) using Idylla™ Biocartis, a fully automated platform that evaluates the most frequent mutations of KRAS, NRAS and BRAF genes. We correlated the results of liquid biopsy and standard tissue-based next generation sequencing (NGS) analyses to patient clinical features. The overall agreement was 81.94%. Concordance was 85.71% and 96.15% in treatment-naïve patients and in the patient subgroup with liver metastases, respectively. In liver metastases positive, treatment-naïve patients, sensitivity, specificity and positive predictive value (PPV) were 92.31%, 100% and 100%, respectively. Circulating mutational fraction (CMF) was significantly higher in patients with liver metastases and high carcinoembryonic antigen (CEA) levels. In a subgroup of patients pre-treated with anti-Epidermal Growth Factor Receptor (EGFR) agents, emerging KRAS mutations were evidenced in 33% of cases. Testing RAS/BRAF mutations on plasma using the Idylla™ Biocartis platform is feasible and reliable in mCRC patients in clinical practice.

Feasibility of next-generation sequencing in clinical practice: results of a pilot study in the Department of Precision Medicine at the University of Campania ‘Luigi Vanvitelli’

“…The emerging of liquid biopsy could overcome this question, also allowing to monitor the progress of specific alterations, as already assessed by various works. [28][29][30][31][32] This study has several limitations: first of all, it was a retrospective evaluation and patients enrolled were chosen by physician-dependent criteria on the basis of what described in materials and methods (but this is what happen also in clinical practice); this latter question influenced also the percentage of targetable alterations because patients with well-known driver mutations were not enrolled (eg, BRAF V600 mutation in melanoma, ERBB2 amplification in BC). Furthermore, a molecular tumour board was not set up to select the best therapy for the patients, even if it could help in most complex case to prioritise treatment options 33 ; besides, no outcome analysis were done because of sample size and the short observation time.…”

Detection of KRAS mutations in liquid biopsies from metastatic colorectal cancer patients using droplet digital PCR, Idylla, and next generation sequencing

“…However, NGS is a more time-consuming and expensive method than ddPCR and Idylla. NGS is most often used for analysis of the primary tumor mutation spectrum, and Idylla liquid biopsy results show an overall agreement of 73-82% when compared with standard tissue-based NGS analysis, which was increased to 96-100% for patients with liver metastases [19,20]. In our series, all mCRC patients had been diagnosed with KRAS mutations in their primary tumor using a limited clinical NGS cancer panel.…”

ctDNA as a Cancer Biomarker: A Broad Overview

“…DNA extracted from the serum is variably fragmented, but representative sequences with characteristic cancer-related aberrations could reproducibly demonstrate suitable amplification and accurate sequencing (Ma et al, 2017). Recently, there has been consensus in the literature that ctDNA obtained by liquid biopsy is a convenient carrier of the actual genetic composition and is potentially more informative than tissue-derived nucleic acids archived from the time of diagnosis (Li et al, 2019;Remon et al, 2019;Vitiello et al, 2019). Additionally, ctDNA is useful for finding therapeutic targets after several cycles of therapy (Bhangu et al, 2018;Garlan et al, 2017).…”