Abstract 2406
Background
The introduction of anti-HER2 therapies such as trastuzumab for HER2+ metastatic breast cancer (MBC) has led to significant improvements to disease progression. We, and others have reported cases of long-term durable complete response to trastuzumab in HER2+ MBC. However, to-date only clinical and molecular analysis of this “exceptional” cohort exists. We hypothesise that genomic copy number alteration (CNA) burden can act as a prognostic measure of predicting response to trastuzumab in long-term never relapse exceptional responders (ExRs) from rapid non-responders (NR).
Methods
We performed whole exome sequencing (WES) on n = 6 never relapse ExRs (med RFS < 149 mo) and n = 5 corresponding NRs (median RFS < 14 mo). Both tumour and adjacent normal tissue (where available) was sequenced by BGI using the NGS illumina HiSeq PR100 (2 x 100 bp) at a mean depth of 56 x. Reads were aligned to the hg19 reference genome using BWA software. Two-sample t-test with unequal variances was used to evaluate total genome CNA burden. Median CNA burden was used to stratify patients into high and low CNA burden groups, binary CNA stratification groups were further assessed using Kaplan-Meier survival estimation.
Results
We analysed the DNA chromosome disruption (fraction of the genome amplified/deleted) and present CNA burden. We observed the overall fraction of genome CNA burden was more destructed (P = 0.07); while more significantly pronounced in the amplification of the whole genome (P = 0.03) in NR compared to ExRs. We further delineated the distribution of CNA burden in all genomes and identified chromosome 8 as significantly disrupted in NRs (P = 0.02). Kaplan Meier survival analysis revealed that low total CNA burden at Chr8 and Chr17 conferred a statistically significant benefit in overall survival (P = 0.009 and P = 0.016, log rank).
Conclusions
CNA burden in HER2+ MBC exceptional responders may represent a novel prognostic predictor to trastuzumab response. Our investigation of genome-wide CNA burden offers the potential to gain insight into the underlying genetic landscape of long-term, never relapse exceptional response to trastuzumab.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Cancer Clinical Research Trust.
Disclosure
G. Gullo: Honoraria (self): Genomic Health; Travel / Accommodation / Expenses: Roche. J. Crown: Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Eisai; Shareholder / Stockholder / Stock options: OncoMark; Honoraria (self): Amgen; Honoraria (self), Research grant / Funding (institution): Puma Technology; Honoraria (self), Advisory / Consultancy: Seattle Genetics; Honoraria (self), Research grant / Funding (institution): Boehringer Ingelheim; Honoraria (self), Advisory / Consultancy, Speaker Bureau / Expert testimony: Pfizer; Honoraria (self): Vertex; Honoraria (self): Genomic Health; Honoraria (self), Research grant / Funding (institution): Roche; Honoraria (self): MSD Oncology. All other authors have declared no conflicts of interest.
Resources from the same session
2860 - Prognostic value of metabolic response assessed by 18FDG-PET after induction chemotherapy and after chemoradiotherapy (CRT) in localized esophageal squamous cell carcinoma (ESCC) patients (pts) receiving definite CRT (dCRT)
Presenter: Yeonghak Bang
Session: Poster Display session 2
Resources:
Abstract
3881 - Comprehensive genomic profiling of early-stage esophageal squamous cell carcinoma
Presenter: Jing Zuo
Session: Poster Display session 2
Resources:
Abstract
3944 - A novel nomogram and risk classification system predicting radiation pneumonitis in patients with esophageal cancer receiving radiotherapy
Presenter: Lu Wang
Session: Poster Display session 2
Resources:
Abstract
1956 - Drinking alcohol, smoking, multiple dysplastic lesions and the risk of field cancerization of squamous cell carcinoma in the esophagus and head and neck region
Presenter: Chikatoshi Katada
Session: Poster Display session 2
Resources:
Abstract
2144 - Neoadjuvant chemotherapy can eliminate the negative impact of postoperative infectious complications on recurrence in patients with esophageal cancer
Presenter: Kazuki Kano
Session: Poster Display session 2
Resources:
Abstract
2403 - Comparison of chemoradiotherapy (CRT) followed by consolidation with cisplatin and 5-fluorouracil (CF) versus definitive CRT with carboplatin and paclitaxel (CP) in esophageal cancer
Presenter: Marcelle Cesca
Session: Poster Display session 2
Resources:
Abstract
3247 - Paclitaxel in Combination with Cisplatin and 5-fluorouracil(TPF) Induction Chemotherapy for Locally Advanced Borderline-resectable Esophageal Squamous cell Carcinoma: A Phase II Clinical Trial
Presenter: Yuhong Li
Session: Poster Display session 2
Resources:
Abstract
4293 - Prognosis of esophageal squamous cell carcinoma based on local immunity evaluation
Presenter: Elena Zlatnik
Session: Poster Display session 2
Resources:
Abstract
5419 - Impact of Sarcopenia and adiposity in survival of metastatic esophageal cancer (MEC)
Presenter: Aline Fares
Session: Poster Display session 2
Resources:
Abstract
2083 - PALAESTRA - A phase II trial with short-course radiotherapy followed by chemotherapy as palliative treatment in esophageal adenocarcinoma
Presenter: David Borg
Session: Poster Display session 2
Resources:
Abstract