
==== Front
Neurooncol Adv
Neurooncol Adv
noa
Neuro-Oncology Advances
2632-2498
Oxford University Press US

10.1093/noajnl/vdae090.027
vdae090.027
Final Category: Biomarkers
AcademicSubjects/MED00300
AcademicSubjects/MED00310
BMRK-05 ASSOCIATION BETWEEN HER2-LOW STATUS AND TIME TO DEVELOPMENT OF BRAIN METASTASES AMONG PATIENTS WITH BREAST CANCER: A RETROSPECTIVE COHORT STUDY
Yijun Fan Kevin University of Toronto, Toronto, Canada

Chehade Rania University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

Fernandes Italo University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

Moravan Veronika VM Stats, Toronto, Canada

Jerzak Katarzyna University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

8 2024
02 8 2024
02 8 2024
6 Suppl 1 2024 SNO/ASCO CNS Metastases Conference i9i9
© The Author(s) 2024. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.
2024
https://creativecommons.org/licenses/by-nc/4.0/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited. For commercial re-use, please contact journals.permissions@oup.com

Abstract

BACKGROUND

Brain metastases (BrM) develop in a high proportion of patients with breast cancer. We aimed to investigate the association between HER2 status (HER2-0, HER2-low, HER2+) and time to BrM development in patients treated for breast cancer BrM.

METHODS

We investigated a cohort of 188 women with metastatic breast cancer (MBC) treated for BrM at Sunnybrook Odette Cancer Centre from 2008-2018, for whom HER2 status was available in either the primary breast cancer (PBC) or metastatic site. We investigated: (1) association between HER2 status of the PBC (when available) and time from PBC to BrM diagnosis (PBC-TTBM), and (2) association between HER2 status of either PBC or metastatic site (the higher level of HER2 expression was utilized when >1 sample was available) and time from MBC to BrM diagnosis (MBC-TTBM).

RESULTS

Median age was 50 years and 54% of patients had >1 BrM. 40 patients had triple-negative breast cancer (TNBC), 77 had HER2+ disease, and 70 had HR+(hormone receptor+)/HER2- disease. Among 129 patients for whom PBC HER2 status was available, median PBC-TTBM was 44 months. HER2-low (n=29) status was associated with shorter PBC-TTBM compared to HER2-0 (n=60) and HER2+ (n=40) status (33 vs. 50 vs. 52 months, p=0.045). Among patients with HR+/HER2- disease, HER2-low status (n=21) was associated with shorter PBC-TTBM compared to HER2-0 status (n=29) (34 vs. 95 months, p<0.001). Among patients with TNBC, PBC-TTBM was similar among patients with HER2-low (n=8) and HER2-0 (n=31) status (24 vs. 27 months, p=0.79). In all patients, median MBC-TTBM was 21 months. MBC-TTBM was similar among patients with HER2-0 (n=58), HER2-low (n=53) and HER2+ (n=77) disease (15 vs.19 vs. 22 months, p=0.75); no differences were observed within the HR+/HER2- and TNBC subgroups.

CONCLUSIONS

HER2-low status is associated with shorter PBC-TTBM, particularly among patients with HR+/HER2- disease.
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