Abstract 5664
Background
Liquid biopsy is a minimally invasive strategy to detect genetic alterations in non-small cell lung cancer (NSCLC) patients. In particular, it is clinically useful for the detection of the EGFR T790M resistance mutation in advanced EGFR-mutated NSCLC patients who had progressed under treatment with an EGFR-TKI. While plasma analysis is commonly performed, sputum could be another potential source for circulating tumor DNA (ctDNA) in NSCLC, which has not yet been entirely evaluated.
Methods
Paired plasma and sputum samples from 23 patients with EGFR-mutated lung adenocarcinoma were analyzed for EGFR exon 19 deletions (del19), L858R, and T790M mutations by droplet digital PCR (ddPCR). All patients had histologically confirmed lung adenocarcinoma with EGFR mutations in their initial tissue biopsy at diagnosis.
Results
Tissue genotyping at diagnosis revealed 18 patients with EGFR del19 and 5 patients with L858R mutations. Among the 18 EGFR del19-positive patients, 8 showed concordant test results in plasma and sputum (2 positive, 6 negative), 6 had del19-positive plasma samples but del19-negative sputum samples, 4 were del19 negative in plasma and del19 positive in sputum. Among 5 L8585R-positive patients, 4 had concordant test results in plasma and sputum (3 positive, 1 negative), one patient was L858R positive in the plasma sample but L858R negative in sputum. In 10 out of 23 patients the T790M mutation was assessed in paired samples, 9 showed concordant test results in plasma and sputum (3 positive, 6 negative), one patient was T790M positive only in the sputum sample.
Conclusions
Our results show a high concordance between plasma and sputum for EGFR L858R and T790M mutation testing. A lower concordance was observed for EGFR del19. Thus liquid biopsy from sputum is a promising strategy that should be further evaluated.
Clinical trial identification
GS1-EK4/479-2017, 20.07.2017 EK-18-172-0918, 08.11.2018.
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
2436 - Development and Validation of an RNA-Seq Assay for Gene Fusions Detection in Formalin-Fixed Paraffin-Embedded Samples
Presenter: Hua Dong
Session: Poster Display session 3
Resources:
Abstract
5271 - A Pilot Study to Implement an Artificial Intelligence (AI) System for Gastrointestinal Cancer Clinical Trial Matching
Presenter: Zhaohui Jin
Session: Poster Display session 3
Resources:
Abstract
4787 - A Blinded Comparison of Patient Treatments to Therapeutic Options Presented by an Artificial Intelligence-based Clinical Decision-support system
Presenter: Suthida Suwanvecho
Session: Poster Display session 3
Resources:
Abstract
5744 - OncOS: scalable and accurate next-generation sequencing analytics for precision oncology and personalized patient care
Presenter: Joe Thompson
Session: Poster Display session 3
Resources:
Abstract
3752 - The association between wearable device physical activity metrics and performance status in oncology: a systematic review
Presenter: Milan Kos
Session: Poster Display session 3
Resources:
Abstract
5820 - SomaticNET: neural network evaluation of somatic mutations in cancer
Presenter: Geoffroy Dubourg-Felonneau
Session: Poster Display session 3
Resources:
Abstract
4771 - Is there a role for Next-generation sequencing (NGS) profiling on metastatic non-colorectal gastrointestinal carcinomas (MNCGIC) in developing countries? A single center experience.
Presenter: Mauricio Ribeiro
Session: Poster Display session 3
Resources:
Abstract
1209 - Metastatic Cancer Whole-Exome Sequencing in daily practice
Presenter: Manon Réda
Session: Poster Display session 3
Resources:
Abstract
5702 - Genomic-Guided Individualized Precision Therapy in Refractory Metastatic Solid Tumor Patients with Extensively Poor Performance Status: A Chinese single institutional prospective observational real-world study
Presenter: Haitao Wang
Session: Poster Display session 3
Resources:
Abstract
4021 - Prospective pathological experience with research biopsies in the context of clinical trials at Vall d’Hebron Institute of Oncology
Presenter: Paolo Nuciforo
Session: Poster Display session 3
Resources:
Abstract