Central Nervous System
PV QA 2 - Poster Viewing Q&A 2
MO_9_2683 - Potential Prognostic Markers for Survival and Neurologic Death in Patients with Breast Cancer Brain Metastases who receive upfront SRS Alone
Monday, October 22
10:45 AM - 12:15 PM
Location: Innovation Hub, Exhibit Hall 3
Potential Prognostic Markers for Survival and Neurologic Death in Patients with Breast Cancer Brain Metastases who receive upfront SRS Alone
R. F. Shenker1, R. T. Hughes2, E. McTyre3, C. M. Lanier2, H. W. Lo4, L. Metheny-Barlow4, A. Thomas5, D. R. Brown6, T. Avery5, B. Pasche4, C. K. Cramer2, S. B. Tatter7, A. Laxton7, K. Watabe8, and M. D. Chan2; 1Wake Forest School of Medicine, Winston Salem, NC, 2Department of Radiation Oncology, Wake Forest School of Medicine, Winston-Salem, NC, 3Wake Forest Baptist Medical Center, Winston-Salem, NC, 4Wake Forest University School of Medicine, Winston-Salem, NC, 5Wake Forest Baptist Health, Winston Salem, NC, 6Wake Forest Baptist Health accruals for Arizona Oncology Services Foundation, Winston-Salem, NC, 7Department of Neurosurgery, Wake Forest School of Medicine, Winston-Salem, NC, 8Department of Cancer Biology, Wake Forest School of Medicine, Winston-Salem, NC
Purpose/Objective(s): SRS is increasingly used as a standard treatment option for breast cancer brain metastases. It is unclear for these patients what are the factors that drive neurologic death. Materials/Methods: Between 7/2001 and 3/2017, a total of 129 patients with breast cancer brain metastases were treated with upfront SRS alone. Survival was estimated using the Kaplan-Meier method. Cumulative incidence (CI) of distant brain failure (DBF) and neurologic death were estimated using competing risk methodology. Clinicopathologic factors including age, ER/PR status, Her2 status, numbers of brain metastases treated, minimum SRS dose, disease-specific GPA, extracranial disease status and systemic disease burden were evaluated as potential predictors of neurologic death using stepwise multivariate subdistribution hazard modeling. Results: Median follow-up was 9.9 months (IQR, 2.7-21.6). Overall survival at 6, 12 and 24 months for the entire population was 78%, 56%, and 31%. Cumulative incidence of distant brain failure at 6, 12 and 24 months for the entire population was 24%, 41%, and 51%. One-year CI of DBF for ER/PR positive, negative, and unknown patients was 47%, 38%, and 12%, respectively (Gray’s p=0.06). Stratified by Her2 status, 1-year DBF rates were 40%, 45% and 12%, respectively (p=0.07). Median brain metastasis velocity (BMV) was 4.86 (IQR 1.8-11.4). BMV was not associated with ER/PR or Her2 status (p=0.50). Cumulative incidence of neurologic death at 6, 12 and 24 months for the entire population was 9%, 17%, and 19%. Cumulative incidence of non-neurologic death at 6, 12 and 24 months for the entire population was 16%, 31%, and 40%. ER or PR positivity was associated with a trend towards decreased neurologic death (sHR = 0.54, p=0.06). Factors associated with non-neurologic death include age (sHR = 1.02, p=0.03) and extracranial disease status (p=0.02); Her2-positivity was associated with reduced hazard of non-neurologic death (sHR 0.52, p=0.05). Cox proportional hazards analysis of patients who experienced DBF revealed BMV to be highly predictive of both OS (HR = 1.03, p<0.01) and neurologic death (HR = 1.04, p<0.01). Conclusion: ER/PR positivity was associated with a trend towards less neurologic death, while HER2 positivity was associated with a trend towards less non-neurologic death. High BMV was associated with both poor prognosis and high rate of neurologic death. If these data can be validated, they would provide important prognostic biomarkers for cause of death in breast cancer brain metastasis patients.
Author Disclosure: R.F. Shenker: None. R.T. Hughes: None. E. McTyre: None. H. Lo: None. L. Metheny-Barlow: None. D.R. Brown: None. T. Avery: None. M.D. Chan: Honoraria; Elekta. Advisory Board; Novocure.