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

10.1093/noajnl/vdae090.026
vdae090.026
Final Category: Biomarkers
AcademicSubjects/MED00300
AcademicSubjects/MED00310
BMRK-04 EFFECT OF PRIMARY CANCER SITE AND EXTRACRANIAL PROGRESSION ON DEVELOPMENT OF BRAIN METASTASES IN PATIENTS TREATED WITH STEREOTACTIC BODY RADIOTHERAPY FOR OLIGOMETASTATIC SOLID TUMORS
Fan Kevin Yijun University of Toronto, Toronto, Canada

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

Kumar Sudhir University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

Moravan Veronika VM Stats, Toronto, Canada

Said Badr Id University of Toronto, Toronto, Canada

Das Sunit University of Toronto, Toronto, Canada
Saint Michael’s Hospital, Toronto, Canada

Louie Alexander University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

Soliman Hany University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

Sahgal Arjun University of Toronto, Toronto, Canada
Sunnybrook Odette Cancer Centre, Toronto, Canada

Chen Hanbo 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

Patients with oligometastatic disease (OMD) may achieve long-term control with stereotactic body radiation therapy (SBRT). However, those who develop brain metastases (BrM) often have poor outcomes. We aimed to investigate variables associated with development of BrM in this population.

METHODS

Patients with ≤5 extracranial metastases from solid tumors treated with SBRT from 2008-2016 at Sunnybrook Odette Cancer Centre were included. We investigated the association between covariates and CIBrM (cumulative incidence of BrM) using Fine-Gray analysis with death as a competing risk, and progression-free survival (PFS) and overall survival (OS) using Cox regression. We investigated the association between widespread extracranial progression (≥5 sites) and CIBrM using a time-based conditional competing-risks analysis.

RESULTS

Among 404 patients, the most common primary sites were lung (32%), colorectal (26%), prostate (13%), breast (10%) and kidney (7%). Median follow-up was 49 months. Median PFS was 25 months and median OS was 70 months. 58 patients developed BrM, and 5-year CIBrM was 16%. The 5-year CIBrM was highest among patients with breast cancer (22%), lung cancer (15%) and kidney cancer (15%), and lowest among those with colorectal cancer (5%) and prostate cancer (0%). On multivariable analysis, primary site was associated with CIBrM (p<0.001), with colorectal cancer (HR 0.34) and prostate cancer (HR 0.00) associated with lower CIBrM compared to lung cancer. Time from primary diagnosis to OMD, number of extracranial metastases, location of metastases, and total planning target volume (PTV) were not associated with CIBrM. Development of widespread extracranial progression within 24 (HR 4.1, p=0.004), 36 (HR 3.7, p=0.013), 48 (HR 5.9 p=0.009) and 60 (HR 23, p=0.017) months of OMD diagnosis was independently associated with higher CIBrM.

CONCLUSIONS

Primary site and extracranial progression, but not baseline measures of OMD volume and distribution, are associated with development of BrM in patients with OMD treated with SBRT.
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