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
5368 - Durvalumab and Paclitaxel Combination for treatment of metastatic triple negative breast cancer is safe with very promising efficacy
Presenter: Hazem Ghebeh
Session: Poster Display session 3
Resources:
Abstract
1520 - A prospective cohort study on the pharmacokinetics of nivolumab in metastatic non-small cell lung cancer, melanoma, and renal cell cancer patients
Presenter: Daan Hurkmans
Session: Poster Display session 3
Resources:
Abstract
1603 - Safety and clinical activity of subcutaneously (SC) administered anti-PD-1 antibody PF-06801591 in phase I dose-expansion cohorts of locally advanced or metastatic non-small-cell lung cancer (NSCLC) and urothelial carcinoma (UC)
Presenter: Byoung Cho
Session: Poster Display session 3
Resources:
Abstract
3922 - Development of the Functional Assessment of Cancer Therapy-Immune Checkpoint Modulator (FACT-ICM): A scale to measure quality of life in cancer patients treated with ICMs
Presenter: Aaron Hansen
Session: Poster Display session 3
Resources:
Abstract
2408 - Immune checkpoint inhibitors (ICIs) as “chemotherapy (Ctx) sensitization” strategy in advanced solid tumors
Presenter: Francisco Javier Ros Montana
Session: Poster Display session 3
Resources:
Abstract
3612 - Validation of progression-free survival (PFS) as surrogate endpoint in randomised trials of immune checkpoint inhibitors in advanced solid cancers
Presenter: Peey Sei Kok
Session: Poster Display session 3
Resources:
Abstract
3827 - Pharmacokinetic (PK) analysis of weight-based and fixed dose cemiplimab in patients (pts) with advanced malignancies
Presenter: Michael Migden
Session: Poster Display session 3
Resources:
Abstract
2120 - A burst of highly differentiated CD4 TL identifies a subset of fast progressors, and correlates with hyperprogressive disease in NSCLC patients treated with ICI
Presenter: Hugo Arasanz
Session: Poster Display session 3
Resources:
Abstract
4254 - Nivolumab treatment in advanced non-small cell lung cancer (aNSCLC): a French nationwide retrospective cohort (UNIVOC Study)
Presenter: Christos Chouaid
Session: Poster Display session 3
Resources:
Abstract
1084 - Dissociated responses in patients with metastatic solid tumors treated with immunotherapy
Presenter: Pauline Vaflard
Session: Poster Display session 3
Resources:
Abstract