Abstract 4590
Background
Liquid biopsies (LB) allow monitoring of genetically different and co-occurring cancer cell clones. In metastatic colorectal cancer (mCRC), circulating-free DNA (cfDNA) can be relevant for monitoring treatment and identification of molecular alterations resulting in disease relapse often earlier than radiological examinations.
Methods
Patients with mCRC at diagnosis and treated with chemotherapy (CT) in combination with antibodies (bevacizumab, cetuximab or panitumumab) before undergoing surgery for resectable disease were included. LB were collected before therapy start, every four weeks during treatment, within ten days of radiological disease evaluation, at radiological relapse and until two months after progression. Next generation sequencing based on plasma samples was performed (testing for mutations and copy number variations covering 77 genes).
Results
From February 2016 to October 2018, 14 patients having surgery after first line treatment were included herein; median follow-up was 21.5 months. Five of them had RAS wild-type disease and received CT plus anti-EGFR treatment, while nine RAS mutated mCRC patients received bevacizumab. Disease relapse happened in seven cases, with subsequent death in three cases. In six out of seven cases, gene alterations were already detected in the pre-operative cfDNA. In the seven cases without disease relapse, gene variants were detected even after the surgery in two patients despite receiving radical resection. Median number of gene variants was two. Beside the well-established mutations in TP53 gene, both APC and ROS1 gene mutations were frequent, while further evaluations are required for the other variants detected.
Conclusions
Evaluation of cfDNA mutations in LB from mCRC may be a useful tool for monitoring clinical response and predict treatment outcome. Moreover, this molecular analysis can help to subgroup patients with regard to risk of relapse after radical surgery. Indeed, cfDNA mutations present before surgery seem to be an indication for a higher risk of post-surgery disease relapse.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
MEDeA Onlus.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4543 - Long-term real-world (RW) outcomes in patients with advanced melanoma (MEL) treated with ipilimumab (IPI) and non-IPI therapies: IMAGE study
Presenter: Stéphane Dalle
Session: Poster Display session 3
Resources:
Abstract
4523 - Prognostic Factors for efficacy of Ipilimumab used after AntiPD1 and/or BRAF+MEK inhibitors in Melanoma Patients: an Italian Melanoma Intergroup study
Presenter: Riccardo Marconcini
Session: Poster Display session 3
Resources:
Abstract
3632 - Rechallenge with combination ipilimumab and anti-PD-1 (IPI+PD1) in metastatic melanoma after acquired resistance to IPI+PD1 immunotherapy
Presenter: Adriana Hepner
Session: Poster Display session 3
Resources:
Abstract
3732 - Clinicopathologic characteristics of immune colitis in melanoma patients treated with combination ipilimumab and anti-PD1 (IPI+PD1) and PD1 monotherapy.
Presenter: Kazi Nahar
Session: Poster Display session 3
Resources:
Abstract
5005 - Real-world outcomes of ipilimumab plus nivolumab for advanced melanoma in the Netherlands
Presenter: Michiel van Zeijl
Session: Poster Display session 3
Resources:
Abstract
5524 - Utilization of Real-World Data to Assess the Effectiveness of Immune Checkpoint Inhibitors (ICIs) in Elderly Patients with Metastatic Melanoma
Presenter: D Scott Ernst
Session: Poster Display session 3
Resources:
Abstract
5884 - Tumor mutational burden and response to PD-1 inhibitors: an analysis of 89 cases of metastatic melanoma.
Presenter: Léa Dousset
Session: Poster Display session 3
Resources:
Abstract
3120 - Increase in S100B and LDH as early outcome predictors for non-responsiveness to anti-PD-1 monotherapy in advanced melanoma.
Presenter: Elisa Rozeman
Session: Poster Display session 3
Resources:
Abstract
2157 - Immune status defined by molecular information layers predicts response to pembrolizumab treatment in advanced melanoma
Presenter: Guillermo Prado-Vázquez
Session: Poster Display session 3
Resources:
Abstract
2553 - Interim analysis of a phase Ib study of cobimetinib plus atezolizumab in patients with advanced BRAFV600 wild type melanoma progressing on prior anti-PD-L1 therapy
Presenter: Shahneen Sandhu
Session: Poster Display session 3
Resources:
Abstract