Abstract

11094 Background: Brain metastases (BM) portend high mortality rates. While whole brain radiation therapy (WBRT) is a commonly used treatment strategy for BM, stereotactic radiosurgery (SRS) has less neurocognitive toxicity with comparable survival. The objective of this study was to compare treatment practice patterns for SRS vs WBRT using a large national hospital database. Methods: The National Cancer Database (NCDB) was queried for patients ≥18 years treated with radiotherapy (RT) for a BM diagnosis between 2004-2017 and with known follow-up. 12 cancers were included based on highest prevalence including: breast, colorectal, kidney/bladder, liver, lung, lymphoma, melanoma, oral cavity, pancreas, prostate, and thyroid. Patients were grouped by first course RT modality (SRS vs WBRT) confirmed by fraction number (SRS: 1-5; WBRT: 5-15). Multivariable logistic regression assessed predictors of SRS as adjusted odds ratios (aOR) with 95% confidence intervals (95%CI). Analyses were adjusted for patient and cancer characteristics. Results: Of 88,539 patients with BM, 17,734 (18%) received SRS. Median age was 64 years. Most patients were White (84%), diagnosed in 2011-2017 (58%), with a higher income (55%), more education (55%), and Medicare/Medicaid (58%). The most common cancer treated with RT for BM was lung (86%). Patients were less likely to be treated with SRS if they were Hispanic (aOR=0.85; 95%CI=0.76-0.96), lower income (aOR=0.90; 95%CI=0.86-0.95), lower education (aOR=0.87; 95%CI=0.83-0.91), with Medicare/Medicaid (aOR=0.83; 95%CI=0.79-0.87) or no insurance (aOR=0.46; 95%CI=0.41-0.51), at a Midwest hospital (aOR=0.74; 95%CI=0.71-0.78; vs Northeast), and at a community (aOR=0.28; 95%CI=0.25-0.30; vs academic) or comprehensive community cancer program (aOR=0.50; 95%CI=0.47-0.52). Patients were more likely to be treated with SRS if they were older (aOR=1.01; 95%CI=1.01-1.01), diagnosed in 2011-2017 (aOR=2.39; 95%CI=2.30-2.49; vs 2004-2010), lived farther from the hospital (aOR=1.09; 95%CI=1.07-1.11), and received chemotherapy (aOR=1.41; 95%CI=1.35-1.47). SRS was most often used to treat BM from primary colorectal cancer (aOR=1.99; 95%CI=1.65-2.40), endometrial cancer (aOR=1.52; 95%CI=1.08-2.10), kidney/bladder cancer (aOR=3.09; 95%CI=2.68-3.55), and melanoma (aOR=2.74; 95%CI=2.39-3.14), while less often used to treat BM from lymphoma (aOR=0.18; 95%CI=0.11-0.30), vs breast primary cancers. Conclusions: In one of the largest BM studies with nearly 90,000 US patients, disparities in SRS treatment patterns were identified. On adjusted analysis, SRS was less likely to be used for patients who were of Hispanic ethnicity, lower income, lower educational attainment, without private insurance, and treated at community centers. The data highlight populations with cancer and BM who may benefit from increased access to SRS.