Study of Prognostic Factors in Patients with Colorectal Cancer and Central Nervous System Metastasis: A Retrospective Analysis

Background: Metastasis of colorectal cancer to the central nervous system (CNS) is relatively rare but leads to shorter survival for these patients, even with improvements in palliative treatments.

Objectives: The primary objective of this study was to assess the overall survival of patients with brain metastasis from colorectal cancer treated at the A.C. Camargo Cancer Center. The secondary objectives were to identify clinical and epidemiological factors, correlate clinicopathological factors with overall survival, and describe prognostic factors associated with CNS metastasis.

Methods: We retrospectively evaluated patients with metastatic colorectal cancer and CNS involvement treated from January 2002 to August 2020 at a single cancer center.

Results: We identified 46 patients with a median age of 63.9 years; 50% were male, and 80% had a good performance status. The predominant primary site was the left colon (71.7%). Sixty percent were stage IV, 71.7% had previously presented with lung metastasis, and 76.7% had a high volume of lung disease. RAS mutations were detected in 56.5% of the pts. Progression to the CNS occurred after a median of three treatment lines, with a median time of 49.5 months between diagnosis and progression to the CNS. Sixty percent had supratentorial lesions, and 55.6% had only one lesion. After a median follow-up time of 27.2 months, the overall survival was 6.4 months. Surgery and radiation were associated with improved overall survival (HR 0.24, 95% CI 0.09-0.67; p = 0.006; and HR 0.20, 95% CI 0.08-0.5; p = 0.001, respectively).

Conclusion: Our study found that most patients with CNS metastasis experienced progression after three lines of palliative treatment, had prior high-volume lung metastasis, and presented with left-sided tumors. Surgery and radiation may improve overall survival.