INTRODUCTION: Breast cancer is a common cause of brain metastases, occurring in at least 10–16 % of patients. Unfortunately, patients who develop brain metastases tend to have a poor prognosis with short overall survival. Moreover, for reasons we do not fully understand, African American women tend to have a worse prognosis and survival rate of about only 17% after 2 years of initial diagnosis of brain metastases. Our hypothesis in this project is that brain metastases in African American patients will have a higher growth rate compared to their white counterparts and that this may partially explain the worse prognosis for this population. However, measurement of growth rates of metastatic brain cancer has not been performed previously. A secondary objective is to test whether a combination of repeat brain MRI scans and dedicated software for automatic tumor sizing can be used to determine growth rates of individual brain lesions in this patient population and statistically correlate these with race and primary tumor type. METHODS: This was a pilot retrospective study of women who had been diagnosed with primary breast cancer that metastasized to the brain where multiple follow-up brain MRI scans were available. We used in-house software built upon the NIH ImageJ package to detect and accurately size nodules from the T1-weighted, post-contrast brain MRI scans[RA ref]. Patient factors of age, race, and primary tumor type we gathered as well as the type of treatment: surgery, chemotherapy, whole-brain radiation therapy, and/or stereotactic radiosurgery. RESULTS: To-date we have analyzed the growth rates of 20 brain metastases in 6 women: 3 Blacks, 3 Whites, 3 with ER+, 3 with ER- primary tumors, and age range 31-86 years. We have still not received sufficient results from our computational studies but will be getting soon. CONCLUSION: We have demonstrated the measurement of growth rates of individual brain metastases using repeated post-contrast brain MRIs and dedicated image analysis software. We have successfully applied these in 10 tumors from 20 breast cancer patients with known metastases to the brain. We have shown that growth rates differ between racial and ER+/- cohorts but additional datasets are needed to establish a statistical correlation. We hope these initial results motivate larger future studies that can investigate the role in breast cancer outcomes of patient and societal factors such as race, age, presence of comorbidities, primary tumor type, the aggressiveness of initial treatment, access to medical care, and socioeconomic factors.

Citation Format: Daniel Sola, Jada Harvey, Walter O'Dell. Examining racial differences in tumor growth rates for metastatic breast cancer to the brain [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-219.