Is there an Ethnic Predisposition to Developing Brain Metastases (BM) in Asian Patients with Colorectal Cancer?

Background: Most common sites of metastases in patients with colorectal cancer (CRC) include liver and lung. Brain metastases are very rare but their presence is associated with a poor prognosis and shorter survival. We report our investigation into the impact of race/ethnicity on the incidence of BM in CRC patients.

Method: We retrospectively reviewed patients diagnosed with CRC from 2010 - 2018 at a single institution and analyzed any association of development of brain metastases with race and ethnicity. Race and ethnicity were defined in accordance with federal standards set by the US Census.

Result: We identified 264 CRC patients and 76(29%) were identified as Asian. Of those 76 patients, 5(7%) developed brain metastases. All 5 patients were male and stage IV at initial diagnosis. Brain metastases was a late stage phenomenon. Median time to development of brain metastases was 29 months (Range: 26 - 33). Median overall survival after BM diagnosis was 5.5 months (Range: 4 - 11). Overall survival was longest for the patient who had both radiation and surgery.

Conclusion: Our study showed an incidence of brain metastases of 7% in the Asian sub-population compared to the historical control of 0.6% - 3.2% in the overall population. These results at the least warrant further investigation in a larger patient population of brain metastases in CRC patients with emphasis on molecular markers.