ESTRO 2025 - Abstract Book

S581

Clinical - Breast

ESTRO 2025

Results: Median follow-up was 42 months (95 % CI 26.65 - 75.34). The median iBMV and v-iBMV was 0.50 BM/yr (IQR 0.21 - 1.23) and 0.62 cc/yr (IQR 0.19 – 3.67), respectively. The median volume of intracranial disease at first diagnosis of BM was 2.56 cc (IQR 0.95 – 13.2), (Table 1). In the Kaplan-Meier estimate an iBMV index above the median of 0.50 BM/yr was significantly associated with a worse overall survival (OS) (p = 0.018) and the v-iBMV index above the median of 0.63 cc/yr in the v-iBMV cohort was also associated with a worse OS (p = 0.028). In the univariate Cox regression, iBMV or v-iBMV above the median was significantly associated with a higher risk of death [p = 0.023; HR 1.99 (95 % CI 1.1 – 3.6) and p = 0.042; HR 3.91 (95% CI 1.1 – 14.5), respectively]. For the v-iBMV subcohort iBMV was not significantly associated with a worse OS (Table 2).

Conclusion: v-iBMV correlates with OS for a subgroup of patients with BCBM. For the same subcohort, iBMV was not predictive for OS, which may indicate a stronger predictive value. Further analyses in a larger subset of patients are necessary to validate these findings and to assess its value in terms of other endpoints like time to brain recurrence.

Keywords: brain metastases, volume, velocity

References: 1.

Soike MH, McTyre ER, Hughes RT, et al (2018) Initial brain metastasis velocity: does the rate at which cancers first seed the brain affect outcomes? J Neurooncol 139:461–467. https://doi.org/10.1007/s11060-018-2888-3