2945 - Descriptive Analysis of Breast Cancer Patients with Brain-Only Metastases Using the National Cancer Database
Presenter(s)
M. R. Harrell1, T. Kutuk1, Y. Gokun2, R. Upadhyay1, M. Mestres-Villanueva1, S. J. Daniel1, S. R. Jhawar1, J. C. Grecula1, R. Raval1, R. Singh1, S. Zhu1, D. M. Blakaj1, A. Chakravarti1, J. D. Palmer1, and S. Beyer1; 1Department of Radiation Oncology, The Ohio State University Wexner Medical Center, Columbus, OH, 2Center for Biostatistics, Department of Biomedical Informatics, The Ohio State University Wexner Medical Center, Columbus, OH
Purpose/Objective(s): Patients with brain-only metastatic breast cancer (BO-MBC) represent a unique clinical subgroup. While treatment of breast cancer brain metastases (BC BM) involves a multi-disciplinary approach of neurosurgery, radiation therapy (RT) and systemic therapy, there is limited data guiding treatment in BO-MBC patients. BM are generally associated with poor prognosis; however, preliminary studies suggest that BO-MBC patients may exhibit prolonged survival and a distinct disease biology and better outcomes. This study characterizes BO-MBC patients using the National Cancer Database (NCDB).
Materials/Methods: The NCDB was queried for breast cancer patients diagnosed between 2010 and 2020 with BM as the only metastatic site. Demographic, tumor, and treatment characteristics were analyzed. Kaplan-Meier survival analysis along with Log Rank Test were used to estimate overall survival (OS).
Results: Among 8,909 patients with MBC to the brain (including extracranial metastases (EM)), 1,540 (17.3%) had BO-MBC in the NCDB. Median age was 62 years (IQR: 52-71). In the 1,091 patients with BO-MBC with known receptor subtypes, 31.3% were ER+/PR+/HER2-, 32.0% were HER2+ and 36.7% were triple-negative. In the entire cohort of 6,480 patients with MBC to brain (including EM) with known receptor subtypes, 40.8% were ER+/PR+/HER2-, 32.8% were HER2+ and 26.2% were triple negative. Among BO-MBC patients, 329 (21.4%) underwent surgical resection of BM; 778 (51.7%) received chemotherapy; 449 (29.6%), hormone therapy; and 214 (14.0%), immunotherapy. In the entire cohort of patients with MBC to the brain, 943 (10.6%) underwent surgical resection; 4,789 (54.8%) received chemotherapy; 3,440 (39.3%), hormone therapy; and 1,626 (18.4%), immunotherapy. In BO-MBC, radiation therapy (RT) for BM was administered in 54.8% (n=844), including whole-brain radiation therapy (WBRT) in 591 (70.0%) and stereotactic radiosurgery (SRS) in 253 (30.0%). In the entire cohort with MBC to the brain, 3,864 (43.4%) received RT (74.1% WBRT and 25.9% SRS). Among BO-MBC patients, the median OS was 12.5 months (95% CI: 10.9-14.4), with 1-year OS of 50% (95% CI: 48%-53%) and 2-year OS of 37% (95% CI: 34%-39%). The median OS for those who received RT was 15.2 months compared to 8.5 months without RT (p<0.001). Within the RT cohort, SRS was associated with improved survival (median OS: 20.4 months vs 13.6 months, p=0.001) and 26% lower mortality risk (HR: 0.74, 95% CI: 0.62-0.88) compared to WBRT. In the entire cohort with MBC to the brain, median OS was 10.9 months (95% CI: 10.4-11.5), 1 year OS was 48% (95% CI: 47%-49%), and 2 yr OS was 34% (95% CI: 33%-35%).
Conclusion: Patients with BO-MBC appear to have good prognosis and benefit from aggressive local therapies, such as surgical resection and RT. Further research is warranted on this patient population, especially with the recent development of CNS-penetrating systemic therapies.