Abstract P4-03-43: Disease characteristics and outcomes of people with metastatic breast cancer in a single center cohort study: The Dallas Metastatic Breast Cancer Study

Abstract Background: Breast cancer is the most common cancer in women, and metastatic disease accounts for most breast cancer related deaths. Identifying risk factors for the onset and progression of metastatic breast cancer (MBC) can help us understand how to address and improve morbidity and mortality due to MBC. Large national databases, such the Surveillance, Epidemiology, and End Results (SEER) Program are limited in their ability to capture granular details from patients’ cancer histories. The Dallas Metastatic Breast Cancer Study (DMBCS) is a clinical database established at a single academic medical system to track patient demographics, associated pathology, treatments, and other variables to improve outcomes for patients with MBC. Methods: The DMBCS database was generated from a registry of breast cancer patients submitted to the National Cancer Institute from 2010 to 2021. Patients were initially excluded if they were identified as non-metastatic from this list. Chart review was then done to identify MBC patients from this subsequent group. Demographics, clinical history, pathologic features, lines of treatment, and subsequent recurrences were collected for all patients. Clinical data was stored in REDCap, a secure data collection platform for entering and managing data. Results: 230 cases were included in this preliminary data set. Of the 230 cases, 185 cases were metastatic at time of diagnosis while 45 cases were metastatic recurrences of breast cancer. At diagnosis, 14.8% were less than 40 years of age, 17.3% were 40-49, 35.7% were 50-59, 18.7% were 60-69, and 13.5% were greater than 70 years of age. In terms of ethnicity, 63.5% were White, 27.4% were Black, and 21.7% identified as Hispanic. At time of diagnosis, 30.9% of patients had a BMI classified as overweight and 40.4% were considered obese. Medical comorbidities included hypertension in 43% of cases, diabetes (18.3%), hyperlipidemia (27.4%), and autoimmune disease (13.0%). Clinical subtype analysis revealed 57.8% of patients were hormone receptor positive, 24.8% HER2 positive, and 17.4% triple negative, at diagnosis. 14.8% of cases were diagnosed as inflammatory breast cancer. The most common site of metastasis at presentation was bone with 69.1% of cases, followed by lung (33.9%), liver (30.0%), and brain (15.2%). Over 90% of patients were treated with at least one antineoplastic regimen and 39.6% underwent at least 4 therapies. Calculated 1-year survival after diagnosis was 85.7%. Conclusions: The introduction of the DMBCS will allow continued investigation into clinical drivers of MBC. In this first cohort of patients, we characterized key, yet often underreported, variables and outcomes. Potential applications of this database include investigating the association between obesity and overall survival in patients with MBC, understanding how socioeconomic disparities affects outcomes of patients with MBC, and exploring correlations between autoimmune disease and the progression of MBC. Citation Format: Meng Cao, Mir Lim, Anna Moscowitz, Jonathan Ladner, Christine Hodgdon, Julia Maues, Sangeetha Reddy, Isaac Chan. Disease characteristics and outcomes of people with metastatic breast cancer in a single center cohort study: The Dallas Metastatic Breast Cancer Study. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-43.