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
3902 - The efficacy of preoperative breast cancer chemotherapy without anti-HER2-targeted treatment – single center experience in setting of no reimbursement in Poland (2011-2015)
Presenter: Agnieszka Badora-Rybicka
Session: Poster Display session 2
Resources:
Abstract
4733 - A Multicentre, International Neoadjuvant (NA), Randomized, Double-blind Phase III Trial comparing FULVESTRANT to a combination of FULVESTRANT and PALBOCICLIB in patients with operable Luminal Breast Cancer (SAFIA Trial)
Presenter: Jean-Marc Nabholtz
Session: Poster Display session 2
Resources:
Abstract
5227 - Outcome of Non-metastatic Male Breast Cancer: 222 patients
Presenter: Ulku Yalcintas Arslan
Session: Poster Display session 2
Resources:
Abstract
5943 - Effects of delayed initiation of adjuvant trastuzumab for non-metastatic, Her2 positive breast cancer in a limited resources setting: ML25232 study final results
Presenter: Samir Beslija
Session: Poster Display session 2
Resources:
Abstract
1725 - Final results of scalp cooling for hair preservation: A single- institution prospective study.
Presenter: Dario Loparco
Session: Poster Display session 2
Resources:
Abstract
3713 - Adjuvant Systemic Therapy in Women with Early Breast Cancer and Intermediate Prosigna ROR Scores: Is Chemotherapy Use Declining? Evidence From a Large Practice
Presenter: Lowell Hart
Session: Poster Display session 2
Resources:
Abstract
818 - Management of early breast cancer in women over 90: A 10 year experience
Presenter: Emily Coffey
Session: Poster Display session 2
Resources:
Abstract
1141 - Evolution in the risk of adverse events of adjuvant endocrine therapy in postmenopausal women with early- stage breast cancer.
Presenter: Daniel Reinhorn
Session: Poster Display session 2
Resources:
Abstract
2277 - Hepatitis B screening and incidence of flare among non-metastatic breast cancer patients treated with anthracyclines
Presenter: Zewen Zhang
Session: Poster Display session 2
Resources:
Abstract
2781 - Effect of denosumab on low bone mineral density in postmenopausal Japanese early breast cancer patients receiving aromatase nhibitors : 36-month results
Presenter: Koichi Sakaguchi
Session: Poster Display session 2
Resources:
Abstract