EPID-17. REAL-WORLD OUTCOMES OF BRAIN METASTASES FROM PANCREATIC CANCER: AN ANALYSIS OF 1266 PATIENTS

Abstract BACKGROUND Brain metastases (BMs) from pancreatic cancer (PC) are uncommon. This study examined patterns of care and clinical outcomes for PC BMs. METHODS A retrospective analysis was conducted on PC BMs patients in the US National Cancer Database between 2010-2020, following STROBE guidelines. Treatments were categorized into systemic therapy (Sys) alone, stereotactic radiosurgery (SRS)±Sys, whole brain radiation (WBRT)±Sys, and no brain-specific treatment (NoTx). Primary outcome was median overall survival (mOS), with corresponding hazard ratio for death (HR) and 95% confidence intervals. Prognostic factors were determined using multivariable Cox proportional-hazards analysis including age, sex, race/ethnicity, insurance, Charlson-Deyo score (CDS), concurrent metastases (CMs), and treatment type. RESULTS Of 170,071 metastatic PC patients, 1,266 (0.7%) PC BM patients were included. 45.7% were female and 81.3% were White. Median age was 66.0 years (IQR:58.0-74.0). 34.4% had bone CMs, 45.4% had lung CMs, 60.2% had liver CMs. 48.1% of patients received NoTx, 22.6% Sys, 12.4% WBRT+Sys, 9.8% WBRT, 4.6% SRS+Sys, and 2.5% SRS. mOS (95% CI) was 2.4 months (2.2-2.5) in patients with BMs and 3.9 months (3.8-3.9) in those without BMs (P<0.001). Amongst BM patients, SRS+Sys had a significantly higher mOS of 7.8 months (6.1-14.3) followed by WBRT+Sys: 5.2 months (4.2-6.8), Sys: 4.8 months (4.2-5.8), WBRT: 2.0 months (1.6-2.2), SRS: 1.8 months (1.4-3.7), and NoTx: 1.2 months (1.0-1.3) (P<0.001). Patients treated with SRS alone (HR:2.9, 1.8-4.7, P<0.001), WBRT alone (HR:2.9, 2.0-4.0, P<0.001), and Sys alone (HR:1.5, 1.1-2.1, P=0.009) had significantly lower survival than with SRS+Sys. Patients treated in nonacademic facilities (HR:1.3, 1.1-1.4, P<0.001) and those with CMs (HR:1.4, 1.2-1.6, P<0.001) had poorer survival. CONCLUSIONS BMs in PC are rare and associated with lower survival. SRS+Sys was associated with the best prognosis, but <5% received it. 48% of patients receiving NoTx had mOS of 1.2 months. Future studies exploring care variations are warranted.