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
5629 - Outcome of triple negative inflammatory breast cancers (TNIBC) treated with dose dense neoadjuvant epirubicin cyclophosphmide, prognostic impact of pre and post neoadjuvant chemotherapy (NAC) tumor infiltrating lymphocytes (TIL) and post NAC lymphovascular invasion
Presenter: Luca Campedel
Session: Poster Display session 2
Resources:
Abstract
5792 - A novel PET parameter for cancer stem cell metabolism: early prediction of chemosensitivity to neoadjuvant chemotherapy in locally advanced breast cancer
Presenter: Chanwoo Kim
Session: Poster Display session 2
Resources:
Abstract
3728 - Using nodal ratio to predict recurrence in patients with 4 or more positive lymph nodes early stage breast cancer
Presenter: Besma Graja
Session: Poster Display session 2
Resources:
Abstract
3395 - Re-sentinel node biopsy for local recurrence after breast-conserving surgery
Presenter: Yuka Matsubara
Session: Poster Display session 2
Resources:
Abstract
4302 - Assessment of prognostic and therapeutic factors in men with breast cancer
Presenter: Daniel Herrero Rivera
Session: Poster Display session 2
Resources:
Abstract
4263 - Genomic Profiling of Chinese Breast Cancer Patients
Presenter: Zhonghua Tao
Session: Poster Display session 2
Resources:
Abstract
2406 - Genome copy number alteration burden represents predictor of response in long-term, never relapse exceptional responders of trastuzumab-treated HER2+ metastatic breast cancer
Presenter: Naomi Walsh
Session: Poster Display session 2
Resources:
Abstract
2575 - Next-generation DNA Sequencing (NGS) Results for Tumors From Phase 2 ABRAZO Study of Talazoparib After Platinum or Cytotoxic Non-Platinum Regimens in Patients (pts) With Advanced Breast Cancer (ABC) and Germline BRCA1/2 (gBRCA) Mutations
Presenter: Nicholas C. Turner
Session: Poster Display session 2
Resources:
Abstract
4499 - FGFR1 and CCND1 gene amplifications are associated with breast cancer resistance to aromatase inhibitors
Presenter: Evgeny Imyanitov
Session: Poster Display session 2
Resources:
Abstract
4110 - Clinicopathologic features of BRCA mutated breast cancer patients: Hacettepe Experience
Presenter: Sercan Aksoy
Session: Poster Display session 2
Resources:
Abstract