Abstract 3870
Background
The incidence of BCBM is increasing as a result of both improved diagnostic techniques and longer survival due to better treatment approaches. However, it is still a challenging situation occasioned by the poor responses to different standard therapies, representing an unmet medical need. Determining the molecular profile may be clinically relevant in order to improve the outcome of our patients (pts).
Methods
This is an observational retrospective study including BC-pts who had undergone surgery of BCBM in Hospital Clinic (Barcelona, Spain) between January 2000 and December 2017. RNA was isolated from FFPE tumor tissue and the expression of 55 BC-related genes was assessed on the nCounter. Median progression free survival (mPFS) and overall survival (mOS) were calculated using the Kaplan-Meier method. The association of the expression of each gene with mPFS was evaluated using univariate Cox-models. The same gene expression assay was tested BCBM-paired primary tumor samples.
Results
20 pts with resected BMBC were included. Median age at diagnosis of BCBM was 57.8years (y). mOS from diagnosis of BCBM was 20.22 months (range, 0.67-64.50months). The intrinsic subtype distribution was 45% Basal-like, 20% HER2-enriched (HER2-E), 10% Luminal A, 20% Luminal B and 5% Normal-like. High expression of ESR1and PGR (determined as above the median) and low expression of MKI67were related with better mOS (p = 0.008, p = 0.038 and p = 0.0165). 9 matched-paired samples of primary BC and BCBM were analyzed and 4 (44.4%) PAM50 discordances (2 Luminal B shifted to Luminal A, 1 Normal-like to Basal-like and 1 HER2-E to Luminal B) were observed. Finally, down-regulation of CD8Aand PDL1expression between primary and BCBM (p = 0.0234 and p = 0.0367, respectively) was observed.
Conclusions
Non-luminal intrinsic subtypes are more prevalent in resected BCBM, and gene expression might predict OS. Our data suggest that BCBM can elude the immune surveillance through downregulation of immune genes leading to an immunosuppressed environment. Our analysis shows the value of analyzing gene expression both by cancer subtype and metastatic origin, but further characterization is needed.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Translational Genomics and Targeted Therapeutics in Solid Tumors, August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain.
Funding
Fundación Científica Asociación Española Contra el Cáncer (PRÁCTICAS AECC CURSO ACADÉMICO 2018 to M.M-L).
Disclosure
M. Vidal: Speaker Bureau / Expert testimony: Roche; Speaker Bureau / Expert testimony: Daiichi Sankyo; Speaker Bureau / Expert testimony: Novartis. M. Muñoz: Travel / Accommodation / Expenses: Roche. A. Prat: Advisory / Consultancy: Nanostring Tech. All other authors have declared no conflicts of interest.
Resources from the same session
4022 - Ribociclib (RIB) plus letrozole (LET) in male patients (pts) with hormone receptor-positive (HR+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) from the CompLEEment-1 trial
Presenter: Mario Campone
Session: Poster Display session 2
Resources:
Abstract
3599 - Comparative effectiveness of palbociclib plus letrozole vs letrozole for metastatic breast cancer in US real-world clinical practices
Presenter: Rachel Layman
Session: Poster Display session 2
Resources:
Abstract
901 - Pharmacokinetics (PK), safety, and efficacy of [fam-] trastuzumab deruxtecan with OATP1B/CYP3A inhibitors in subjects with HER2-expressing advanced solid tumors
Presenter: Yung-Jue Bang
Session: Poster Display session 2
Resources:
Abstract
2777 - A Phase 2 study of abemaciclib in patients (pts) with brain metastases (BM) secondary to non-small cell lung cancer (NSCLC) or melanoma (MEL).
Presenter: Solmaz Sahebjam
Session: Poster Display session 2
Resources:
Abstract
3980 - Ribociclib (RIB) + letrozole (LET) in patients (pts) with visceral metastases (VM) or bone-only metastases (BOM) in hormone receptor-positive (HR+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC): Subgroup analysis from the CompLEEment-1 trial
Presenter: Michelino De Laurentiis
Session: Poster Display session 2
Resources:
Abstract
4024 - Ribociclib (RIB) + letrozole (LET) in patients (pts) with hormone receptor-positive (HR+), human epidermal growth factor receptor-2–negative (HER2–) advanced breast cancer (ABC) and central nervous system (CNS) metastases: Subgroup analysis from the phase 3b CompLEEment-1 trial
Presenter: Paul Cottu
Session: Poster Display session 2
Resources:
Abstract
2151 - Clinical outcome and toxicity data in patients with advanced breast cancer treated with cyclin-dependent kinase 4/6 (CDK4/6) inhibitors combined with endocrine therapy in a real-world clinical setting.
Presenter: Elena Fountzilas
Session: Poster Display session 2
Resources:
Abstract
3994 - Safety and efficacy of Ribociclib (RIBO) + letrozole (LET) in patients (pts) with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2–) advanced breast cancer (ABC): Interim results from the Italian cohort of the CompLEEment-1 (C-1) study.
Presenter: Michele De Laurentiis
Session: Poster Display session 2
Resources:
Abstract
1370 - Interim Results From CompLEEment-1 (A Phase 3b Study of Ribociclib and Letrozole as First-Line Therapy for Advanced Breast Cancer in an Expanded Population): Spanish cohort results
Presenter: Javier Salvador
Session: Poster Display session 2
Resources:
Abstract
1109 - First Canadian Interim Analysis from the Phase IIIb CompLEEment-1 Ribociclib + Letrozole HR+ HER2- Advanced Breast Cancer Trial
Presenter: Cristiano Ferrario
Session: Poster Display session 2
Resources:
Abstract