EPID-14. PATTERNS OF CARE AND PROGNOSTIC FACTORS FOR PATIENTS WITH BRAIN METASTASES FROM COLON CANCER: A REAL-WORLD STUDY

Abstract BACKGROUND Brain metastases (BMs) from colon cancer (CC) have limited published literature. This work sought to examine patterns of care and prognostic factors for patients with CC BMs. METHODS A retrospective study was conducted on patients with CC BMs in the National Cancer Database between 2010-2020 and reported using STROBE guidelines. Treatment was stratified into receipt of stereotactic radiosurgery only (SRS), whole brain radiation only (WBRT), systemic therapy only (Sys), combination therapy, and no brain-directed treatment (NoTx). Median overall survival (mOS) and prognostic factors were determined using multivariate cox proportional hazards adjusting for age, sex, race/ethnicity, insurance, Charlson-Deyo score (CDS), concurrent metastases (CMs), and treatment. Outcomes were reported as hazard ratio (HR) and 95% confidence intervals. RESULTS Among 1,383 BMs patients, median age was 64.0 years (IQR 56.0-73.0). 46.4% were female and 81.2% were White. Overall mOS (95% CI) was 5.6 months (4.5-6.2). 26.1% had bone, 71.5% had lung and 72.4% had liver CMs. 24.4% underwent WBRT+Sys, 22.6% NoTx, 18.5% Sys, 14.8% SRS+Sys, 14.7% WBRT, and 5.0% SRS. Patients who underwent SRS+Sys had the highest mOS of 14.4 months (12.8-16.3) followed by Sys: 11.6 months (8.6-13.4), WBRT+Sys: 9.5 months (8.5-10.9), SRS: 3.2 months (2.5-4.4), WBRT: 2.5 months (2.2-2.8), and NoTx: 2.5 months (2.2-2.8) (P<0.001). Patients treated with WBRT+Sys (HR:1.2, 1.0-1.5, P=0.028), SRS alone (HR:1.8, 1.4-2.5, P<0.001), WBRT alone (HR:3.6, 2.9-4.4, P<0.001), NoTx (HR:2.5, 2.0-3.0, P<0.001) was associated with significantly lower survival than SRS+Sys. Patients treated at non-academic facilities (HR:1.1, 1.0-1.3, P=0.038), with Medicare-insurance (HR:1.2, 1.1-1.5, P=0.013) and with left-sided mCC (HR:0.8, 0.7-0.9, P<0.001) had lower survival. CONCLUSIONS SRS+Sys was associated with the highest survival in patients with CC BMs, however only 14.8% received it. Notably, 22.6% of patients received NoTx. Further prospective studies exploring factors behind heterogeneity in clinical care are warranted.