Epidemiology and Outcomes of Patients With Brain Metastases From Colorectal Cancer-Who Are These Patients?

Background: Brain metastases (BMs) from colorectal cancer (CRC) are unusual; however, an increase in incidence has been reported. The evidence available on the subject is scarce, and a better understanding is warranted. We aimed to characterize the epidemiology and the outcomes of patients with BMs from CRC.

Patients And Methods: A cohort of patients with BMs from CRC was retrospectively evaluated. Patients were treated in a single center between May 2008 and April 2019. BMs were confirmed by brain computed tomography or magnetic resonance imaging.

Results: A total of 247 consecutive patients were evaluated. Most patients had a left-sided primary tumor (193, 78%) and at least two extra-cranial metastatic sites (194, 78%). Ninety-six patients (39%) were RAS wild-type; 68 patients (27%) were RAS mutated; and 83 patients (34%) were not characterized. Median time from the initial diagnosis to BMs was 27.6 months (interquartile range, 13.1-46.9). Regarding local therapy, 43 patients (17.4%) were treated with BM surgery alone, 76 patients (30.8%) with radiotherapy (RT) alone, and 58 patients (23.5%) with both surgery and RT. Median overall survival (OS) was 2.9 months (95% confidence interval [CI], 2.2-3.5). Six-month and 1-year OS rates were 29% (95% CI, 23-25) and 13.5% (95% CI, 9.2-18.6), respectively. In a multivariable analysis, BM surgery alone (hazard ratio [HR], 0.56; P = .018), RT alone (HR, 0.51; P = .001), and surgery plus RT (HR, 0.27; P < .001) were associated with superior OS, whereas Eastern Cooperative Oncology Group Performance Status 3 or 4 (HR, 2.01; P = .009) and male gender (HR, 1.46; P = .012) were negative prognostic factors. RAS status was not associated with OS.

Conclusion: BMs occur late during the course of colorectal cancer and are more common in patients with a left-sided primary tumor and a high volume of metastatic disease. BMs from colorectal cancer are still associated with an extremely poor prognosis; however, selected patients may benefit from treatment with surgical resection and radiotherapy.