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
5389 - Two-weekly accelerated BEP (aBEP) regimen as induction chemotherapy (CT) in intermediate and poor prognosis patients (pts) with nonseminomatous germ cell tumors (NSGCT): final results of phase II trial.
Presenter: Alexey Tryakin
Session: Poster Display session 3
Resources:
Abstract
2934 - Differential expression of circulating miR375 and miR371 to detect teratoma and viable germ cell malignancy
Presenter: Lucia Nappi
Session: Poster Display session 3
Resources:
Abstract
3585 - Prognosis of anaemia in disseminated testicular germ cell tumours. On behalf of the Spanish Germ Cell Cancer Group (SGCCG)
Presenter: Esmeralda Garcia Torralba
Session: Poster Display session 3
Resources:
Abstract
2254 - The Effects Of Primary Testicular Tumor Localization On Prognosis In Patients With Nonseminomatous Testis Cancer
Presenter: Birol Yildiz
Session: Poster Display session 3
Resources:
Abstract
4505 - Initial Results of a Phase II study of Nivolumab and Ipilimumab in Metastatic Adrenal Tumors.
Presenter: Matthew Campbell
Session: Poster Display session 3
Resources:
Abstract
3369 - NEMIO: a randomized phase II trial evaluating efficacy and safety of dose dense MVAC (ddMVAC) + durvalumab +/- tremelimumab as neoadjuvant treatment in patients with bladder muscle-invasive urothelial carcinoma
Presenter: Constance Thibault
Session: Poster Display session 3
Resources:
Abstract
2075 - KEYNOTE-866: Phase 3 Study of Perioperative Pembrolizumab (pembro) or Placebo (pbo) in Combination With Neoadjuvant Chemotherapy in Cisplatin (cis)-Eligible Patients (pts) With Muscle-Invasive Bladder Cancer (MIBC)
Presenter: Arlene Siefker-Radtke
Session: Poster Display session 3
Resources:
Abstract
4824 - KEYNOTE-905: A Phase 3 Study of Cystectomy Plus Perioperative Pembrolizumab Versus Cystectomy Alone in Cisplatin (cis)-Ineligible Patients (pts) With Muscle-Invasive Bladder Cancer (MIBC)
Presenter: Matthew Galsky
Session: Poster Display session 3
Resources:
Abstract
2253 - Phase 3 LEAP-011 trial: First-Line Pembrolizumab With Lenvatinib in Patients With Advanced Urothelial Carcinoma Ineligible to Receive Platinum-Based Chemotherapy
Presenter: Yohann Loriot
Session: Poster Display session 3
Resources:
Abstract
4310 - PULSE : A Single Arm Trial Assessing The Activity and Safety of Avelumab Immunotherapy Maintenance among Patients With Locally Advanced or Metastatic Squamous Cell Penile Carcinoma (mSCPC).
Presenter: Noemie Gassian
Session: Poster Display session 3
Resources:
Abstract