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
2142 - Low NK Cell Abundance Correlates with High Expression of PD-1 in CD8+ T Cells
Presenter: Moon Hee Lee
Session: Poster Display session 3
Resources:
Abstract
5501 - Tobacco smoking is associated with the immune suppressive microenvironment in head and neck squamous cell carcinoma (HNSCC)
Presenter: Christine Chung
Session: Poster Display session 3
Resources:
Abstract
5726 - Evaluation of Antibody-Dependent Cell Cytotoxicity (ADCC) in lung cancer cell lines treated with combined anti-EGFR and anti-PD-L1 therapy.
Presenter: Francesca Sparano
Session: Poster Display session 3
Resources:
Abstract
2534 - Radiomic Signatures for Identification of Tumors Sensitive to Nivolumab or Docetaxel in Squamous Non-Small Cell Lung Cancer (sqNSCLC)
Presenter: Laurent Dercle
Session: Poster Display session 3
Resources:
Abstract
3366 - Analysis of gut microbiota in advanced non-small cell lung cancer (NSCLC) patients treated with immune-checkpoints blockers
Presenter: FEIYU ZHANG
Session: Poster Display session 3
Resources:
Abstract
2089 - Pathogenesis of Myocarditis Following Treatment with Immune Checkpoint Inhibitors in a Cynomolgus Monkey Model
Presenter: Changhua Ji
Session: Poster Display session 3
Resources:
Abstract
4463 - Effects of dietary restriction in cancer patients receiving irinotecan
Presenter: Ruben Van Eerden
Session: Poster Display session 3
Resources:
Abstract
4841 - Investigating the Link between Burn Injury and Tumorigenesis
Presenter: Lucy Barrett
Session: Poster Display session 3
Resources:
Abstract
4619 - Prognostic value of the neutrophil-lymphocyte, platelet-lymphocyte and monocyte-lymphocyte ratio in male breast cancer patients
Presenter: Joanna Huszno
Session: Poster Display session 3
Resources:
Abstract
1122 - Platelets from metastatic cancer patients have increased aggregation and activation
Presenter: Meera Chauhan
Session: Poster Display session 3
Resources:
Abstract