PRCA-07 RISK FACTORS AND OVERALL SURVIVAL IN STAGE IV COLORECTAL CANCER PATIENTS WHO DEVELOP BRAIN METASTASIS: A POPULATION-BASED STUDY FROM 2013-2023

Abstract Colorectal cancer (CRC) is the third most common cancer globally. Though rare, brain metastasis (BM) in CRC patients significantly impacts morbidity and mortality. The incidence of BM is expected to rise due to improved screening and treatments extending survival, with BM being more common in Stage IV CRC. However, no screening guidelines currently exist for detecting BM, especially in Stage IV CRC patients. Adult CRC patients, diagnosed between January 1, 2013, and December 31, 2023, with and without BM, were identified via ICD-10 codes from the TrinetX Oncology database. Statistical analyses were conducted using TrinetX. The "incidence and prevalence" function assessed BM prevalence, the "explore cohorts" function analyzed BM diagnoses over time, the "compare cohorts" function compared patient demographics and oncological characteristics, and the "compare outcomes" function generated Kaplan-Meier survival curves. Among 8,621 Stage IV CRC patients, 279 (3.4%) developed BM. Patients with lung (OR [95%CI]: 1.67 [1.11-2.57]) or bone metastasis (OR [95%CI]: 4.30 [3.05-5.85]) had higher odds of developing BM compared to those without such metastases. Liver-only metastasis decreased BM risk (OR [95%CI]: 0.14 [0.09-0.19]). Patients with liver (HR [95%CI]: 1.35 [1.11-1.64]), lung (HR [95%CI]: 1.98 [1.62-2.43]), or bone metastasis (HR [95%CI]: 1.69 [1.42-2.07]) had poorer survival with BM development. BM developed most rapidly in patients with bone metastasis, at a median of less than six months, compared to nine months to one year for liver or lung metastasis. Stage IV CRC patients with pulmonary or bone metastases are at higher risk for BM and should undergo increased surveillance for early detection of brain metastases to improve survival.