Abstract 5640
Background
The aim of this study was to assess the prognostic and predictive value of an untargeted assessment of tumor fractions in the plasma of metastatic breast cancer patients and to compare circulating tumor DNA (ctDNA) with circulating tumor cells (CTC) and conventional tumor markers.
Methods
Patients and methods: 29 patients with metastatic breast cancer were included in this single-institution observational cohort study. Blood samples were obtained at first diagnosis of metastases, during several lines of treatment, and/or at every further moment of progression/development of new metastases. We assessed tumor fractions in plasma using an untargeted mFAST-SeqS method. CTCs were captured using a sized-based microfilter and identified as nucleated, cytokeratin positive/CD45 negative cells. Resulting ctDNA z-scores were compared to tumor fractions established with the recently published ichorCNA algorithm and associated with the clinical outcome.
Results
We observed a close correlation between mFAST-SeqS z-scores and ichorCNA ctDNA quantifications. Patients with mFAST-SeqS z-scores above three (34.5%) showed significantly worse overall (p = 0.014) and progression-free survival (p = 0.018) compared to patients with lower values. Elevated z-score values were clearly associated with radiological proven progression. In contrast, baseline CTC count, CEA, and CA15-5 had no prognostic impact on the outcome of patients in the analyzed cohort.
Conclusions
This proof of principle study demonstrates the prognostic impact of ctDNA levels detected with mFAST-SeqS as a very fast and cost-effective means to assess the ctDNA fraction without prior knowledge of the genetic landscape of the tumor. Furthermore, mFAST-SeqS-based ctDNA levels provided an early means of measuring treatment response.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Krebshilfe Steiermark.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
2107 - Role of Individualized Intervention(s) on Quality of Life (QOL) and Adherence to Adjuvant Endocrine Therapy in Premenopausal Women with Early-Stage Breast Cancer (BC): MyChoice Study
Presenter: Shahid Ahmed
Session: Poster Display session 2
Resources:
Abstract
5812 - Correlation between the density of tumor-infiltrating lymphocytes, immune cell subsets in tumor stroma and response to systemic therapy in breast cancer
Presenter: Cvetka Grasic Kuhar
Session: Poster Display session 2
Resources:
Abstract
4734 - BRCA1/2 Testing in HER2- Advanced Breast Cancer (ABC): Results from the European Component of a Multi-Country Real World Study
Presenter: Michael Patrick Lux
Session: Poster Display session 2
Resources:
Abstract
1686 - In vitro and in vivo rescue of resistance to BET inhibitors by targeting PLK1 in triple negative breast cancer.
Presenter: Cristina Nieto-jiménez
Session: Poster Display session 2
Resources:
Abstract
5020 - Neoadjuvant endocrine therapy in combination with melatonin and metformin in locally advanced breast cancer
Presenter: Tatiana Semiglazova
Session: Poster Display session 2
Resources:
Abstract
5082 - Melatonin and metformin in neoadjuvant chemotherapy in locally advanced breast cancer
Presenter: Tatiana Semiglazova
Session: Poster Display session 2
Resources:
Abstract
2642 - Patient-tailored tamoxifen dosing based on an increased quantitative understanding of its complex pharmacokinetics: A novel integrative modelling approach
Presenter: Anna Mueller-Schoell
Session: Poster Display session 2
Resources:
Abstract
2461 - Lack of benefit of neoadjuvant pertuzumab in high risk HER2 positive breast cancer. A retrospective case-control study of 355 cases with biomarker analysis.
Presenter: Manuela Tiako Meyo
Session: Poster Display session 2
Resources:
Abstract
4776 - Targeting CDCA3 to improve chemotherapy response in triple-negative breast cancer patients
Presenter: Kenneth O'Byrne
Session: Poster Display session 2
Resources:
Abstract
1674 - Activity of BET-proteolysis targeting chimeric (PROTAC) compounds in triple negative breast cancer
Presenter: María Del Mar Noblejas López
Session: Poster Display session 2
Resources:
Abstract