Local Treatment Strategies for Brain Metastases of Colorectal Cancer

Inclusion Criteria: * Male and female patients aged 18 years or older; * Histologically confirmed epithelial malignancy of the colon or rectum (colorectal adenocarcinoma). Patients with synchronous or metachronous multiple primary tumors within the colon or rectum are eligible; * Radiologically ± histologically confirmed brain metastases, including: * Solid brain parenchymal metastases * Leptomeningeal disease (LMD) * Both solid metastases and LMD Exclusion Criteria: * Synchronous or metachronous multiple primary malignancies (MPM) involving sites other than the colon or rectum * Primary tumor located outside the gastrointestinal tract; * Histologically confirmed non-epithelial gastrointestinal malignancy (e.g., neuroendocrine tumors, sarcoma, gastrointestinal stromal tumor, lymphoma); * Isolated spinal cord involvement without brain parenchymal metastases; * Incomplete medical records precluding assessment of at least one primary endpoint (OS, TTIP, or CNS-PFS). Patients with available data for any primary endpoint are eligible, even if other clinical details are missing. * Prior local treatment for brain metastases at an outside institution with no available records, precluding determination of the first local treatment modality