259P Analysis of survival outcomes in breast cancer patients with brain metastases: A comprehensive study utilizing the National Cancer Database

Up to 30% of metastatic breast cancer (MBC) patients (pts) develop brain metastases (BM), significantly impacting prognosis with long-term survival being rare. This increasing incidence poses a major clinical challenge, as treatment options remain limited, and prognosis has not notably improved over decades. BM is a poor prognostic factor for breast cancer survival. Our study utilized the comprehensive National Cancer Database (NCDB) to assess survival outcomes and identify disparities and influential factors among different breast cancer subtypes with BM. This retrospective study examined a cohort of MBC pts with BM from the NCDB database between 2018 and 2021. Tumors were stratified by subtype: hormone receptor-positive (HR+) /HER2-, HER2+, triple-negative breast cancer (TNBC) (ER-/PR-/HER2-). Our statistical analysis plan included Kaplan-Meier survival estimates, log-rank tests for the survival comparision. Cox multivariate analysis was performed to evaluate factors associated survival. Among a total of 732, 777 MBC pts, we identified 2, 741 pts (0. 4%) with BM. The majority were HR+/HER2- (72. 7%), followed by HER2+ (14. 8%) and TNBC (12. 4%). HR+/HER2- pts had a median OS (mOS) of 18. 8 months (95% CI: 16. 7-22. 5 months) and a 5-year survival rate of 0%. HER2+ pts had a mOS of 21. 7 months and a 5-year survival rate of 28. 3% and TNBC pts had 5. 8 months and 0%, respectively. Demographic factors affected outcomes: Asians had better survival than Whites (HR=0. 88), Medicare beneficiaries fared better than those with private insurance (HR=0. 86), and higher Charlson-Deyo scores (≥3) increased mortality risk (HR=1. 14). Higher income (> 74, 063) and treatment at Comprehensive Cancer Centers (HR=0. 947) were linked to improved survival. The longest mOS demonstrated in HER2+ pts is likely reflective of multiple treatment options. In contrast, there are opportunities to improve outcomes for TNBC. Further studies to address the underlying etiology of the differences identified by race are warranted. Worse comorbidity scores were associated with higher mortality. Future research should create targeted interventions to enhance outcomes for all MBC patients with BM.