712 Background: 25% of patients with colorectal cancer(CRC) present with synchronous metastatic disease. The incidence of brain metastasis (BM) in CRC is very low (1.2–3.2%) and tend to occur later in the disease course. Synchronous BM(SBM) in CRC is very rare. We sought to explore the impact of primary tumor characteristics on SBM. Methods: Surveillance Epidemiology End Results Program (SEER) 18 registries research data on primary colorectal cancer cases diagnosed during 2010-2015 with brain metastasis at diagnosis were identified. Patients with unlabeled primary site and autopsy alone cases were excluded. Demographic and colorectal cancer characteristics including age, gender, race, tumor grade and primary tumor side were analyzed. Logistic regression model was used to test the association between survival and side of cancer. Results: A total of 475 cases met the inclusion criteria. The mean age was 64.04 yrs. (range 28-95). Majority of the patients (80%) were white, 12% black and others (8%), Male: Female ratio was 1:1.58% patients had primary tumor on left side (splenic flexure, sigmoid, rectosigmoid and rectal) and 42% had right sided (ascending colon, hepatic flexure, cecum, transverse colon) primary tumor. The median overall survival was 5 months with 1-year survival of 26% in the whole cohort. The 1-year overall survival was 21% for patients with right sided primary tumor versus 30% for patients with SBM and left sided primary tumor(p = 0.03). The median disease specific survival was 5 months for right side and 7 months for Left sided tumor with SBM. The regression model showed that higher grade (RR 14, p = 0.003)) and right sided primary tumor (RR 4.2, p = 0.04) were associated with worse outcome among patients with SBM in colorectal cancer. Conclusions: Synchronous brain metastasis is very rare in colorectal cancer. Tumor side seems to be prognostic even in this aggressive disease subset. This differential outcome further indicates that sidedness should be considered in goals of care and treatment discussion.
EP1.15-13 Prognosis of Colorectal Cancer Cases That Underwent Lung and Liver Metastasectomy and Therapeutic Outcomes of Brain Metastasis
