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
4097 - Targeting NRG1-fusions in multiple tumour types: Afatinib as a novel potential treatment option
Presenter: Stephen V Liu
Session: Poster Display session 3
Resources:
Abstract
1129 - Aspirin and Ticagrelor for the prevention of tumour cell induced platelet aggregation
Presenter: Meera Chauhan
Session: Poster Display session 3
Resources:
Abstract
4514 - Pharmacokinetic/ pharmacodynamic (PK/PD) exposure-response characterization of GSK3359609 (GSK609) from INDUCE-1, a phase I open-label study
Presenter: Michele Maio
Session: Poster Display session 3
Resources:
Abstract
5169 - In vitro functional interrogation of viable Circulating Tumor Associated Cells (C-TACs) for evaluating Platin resistance.
Presenter: Stefan Schuster
Session: Poster Display session 3
Resources:
Abstract
5827 - Targeting ARG2 as a novel therapeutic approach for cancer
Presenter: Marcin Grzybowski
Session: Poster Display session 3
Resources:
Abstract
3129 - MPS1 and PLK1 as new therapy targets in TP53 mutated solid tumors
Presenter: Balazs Gyorffy
Session: Poster Display session 3
Resources:
Abstract
2129 - The Tumor Static Exposure (TSE) concept & utility: application to combination treatment of radiation and radiosensitizing agent in tumor xenograft experiments
Presenter: Samer El Bawab
Session: Poster Display session 3
Resources:
Abstract
1814 - General Methodology to Optimize Tumor Treating Fields Delivery Utilizing Numerical Simulations
Presenter: Noa Urman
Session: Poster Display session 3
Resources:
Abstract
3010 - The Australian Exceptional Responders Program: a National collaboration
Presenter: Megan Barnet
Session: Poster Display session 3
Resources:
Abstract
4489 - A Window of Opportunity Trial of Atorvastatin Targeting p53 Mutant Malignancies
Presenter: Joaquina Baranda
Session: Poster Display session 3
Resources:
Abstract