Presenter(s)
W. Lee1,2, K. Feng1,2, T. Wu1, M. Zhang1, A. Kim1, R. Musoke1, A. Nichol1, R. Ma1, J. Chan1, and J. Oh1; 1Department of Radiation Oncology, BC Cancer, Vancouver, BC, Canada, 2University of British Columbia, Faculty of Medicine, Vancouver, BC, Canada
Purpose/Objective(s): Brain metastases (BM) are common in cancer patients and often treated with radiation therapy (RT). However, intracranial hemorrhage after RT can lead to significant neurologic disability or death. The variables that may contribute to an increased risk of hemorrhage after RT are not fully understood; hence, this study aims to describe the risk and clinical factors associated with hemorrhage following RT for BM in British Columbia between 2017 and 2022. The hypothesis is that patients receiving focal RT or with specific comorbidities have higher risk of post-RT hemorrhage.
Materials/Methods: Patients who received RT for BM from 2017-2022 were identified from a registry at one institution. Primary cancer histologies associated with higher rate of intracranial hemorrhage based on literature review were selected. These included melanoma, renal, colorectal, hepatocellular, head and neck, germ cell and sarcoma. Demographics, treatment characteristics, and post-treatment outcomes were retrospectively reviewed. Fine & Gray competing-risks cumulative incidence of hemorrhage from time of RT and regression was used for univariable (UVA) and multivariable analyses (MVA).
Results: 319 patients were identified. Median age at RT was 64 years. From the time of RT, the median follow-up was 4.3 months [1.6-10.9], and median OS was 4.4 months (95% CI 3.6-5.2). 1-year cumulative incidence of post-RT hemorrhage was 13% and 1-year OS was 15%. Patients had the following risk factors: 134 (42%) hypertension, 75 (24%) anticoagulants, 38 (12%) alcohol abuse, 25 (8%) stroke, 22 (7%) kidney disease, and 12 (4%) liver disease. A history of stroke had an increased risk of post-RT hemorrhage (HR 1.74, p = 0.05), while other factors were not statistically significant. 152 (48%) patients received whole brain RT (WBRT), 83 (26%) stereotactic RT (SRT), and 48 (15%) focal volumetric modulated arc therapy. Relative to SRT, WBRT had a lower risk of hemorrhage (HR 0.28, p = 0.001). UVA for equivalent dose in 2-Gy fractions was not significantly associated with hemorrhage risk. Compared to other histologies, melanoma was associated with increased post-RT hemorrhage (p = 0.03). 13% (41/319) patients developed post-RT hemorrhage and 78% (32/41) of them died, while 63% (26/41) of them developed neurological symptoms such as headache. Median time to death after developing symptoms was 2 months.
Conclusion: UVA and MVA of population-based data from 2017-2022 indicated that different RT modalities and history of stroke influence the risk of post-RT intracranial hemorrhage. Post-RT hemorrhage is not uncommon. Most patients who developed hemorrhage experienced neurological symptoms, and a subset died. These findings underscore the importance of recognizing the influence of RT technique and patient-specific factors on the risk of post-RT hemorrhage, lending understanding to the clinical consequences and morbidity in this population.