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
5705 - External validation and longitudinal extension of the LIPI (Lung Immune Prognostic Index) for immunotherapy outcomes in advanced non-small cell lung cancer.
Presenter: Jakob Riedl
Session: Poster Display session 3
Resources:
Abstract
5758 - Changes of TCR Repertoire in Metastatic Renal Cell Carcinoma and Metastatic Melanoma Patients Treated with Nivolumab
Presenter: Martin Klabusay
Session: Poster Display session 3
Resources:
Abstract
1743 - Expression of MHC class I, HLA-A and HLA-B identifies immune activated breast tumors with favorable outcome
Presenter: María Del Mar Noblejas López
Session: Poster Display session 3
Resources:
Abstract
2219 - Prognostic Significance of Tumor Tissue NeuGcGM3 Ganglioside Expression and Predictive Value of Circulating Tumor Cell Count Monitoring in Patients Receiving Racotumomab Immunotherapy
Presenter: Necdet Üskent
Session: Poster Display session 3
Resources:
Abstract
2996 - Evolution of Myeloid-Derived Suppressor Cells and Objective Response Rate in Relapsed/Refractory Diffuse Large B Cell Lymphoma (R/R DLBCL) patients after receiving immunotherapy
Presenter: Carlos Jiménez Cortegana
Session: Poster Display session 3
Resources:
Abstract
2110 - A Phase Ia/Ib trial of the anti-programmed death-ligand 1 (PD-L1) human monoclonal antibody (mAb), CS1001, in patients (pts) with advanced solid tumors or lymphomas
Presenter: Lin Shen
Session: Poster Display session 3
Resources:
Abstract
3515 - Results from a randomised Phase 1/2 trial evaluating the safety and antitumour activity of anti-PD-1 (MEDI0680)/anti-PD-L1 (durvalumab) vs anti-PD-1 (nivolumab) alone in metastatic clear cell renal cell carcinoma (ccRCC)
Presenter: Martin Voss
Session: Poster Display session 3
Resources:
Abstract
3566 - Pembrolizumab in Advanced Rare Cancers
Presenter: Aung Naing
Session: Poster Display session 3
Resources:
Abstract
3567 - High clinical benefit rates of pembrolizumab in very rare sarcoma histotypes: first results of the AcSé Pembrolizumab study
Presenter: Jean-Yves Blay
Session: Poster Display session 3
Resources:
Abstract
2421 - Lenvatinib plus PD-1 blockade in advanced bile tract carcinoma.
Presenter: Jianzhen Lin
Session: Poster Display session 3
Resources:
Abstract