Comparative survival outcome of synchronous and metachronous brain metastasis from colorectal cancer: A meta‑analysis

Synchronous and metachronous brain metastases (BM) are increasingly recognized in patients with colorectal cancer (CRC). This study aimed to assess whether the timing of BM development affects survival outcomes by conducting a systematic review and meta-analysis. A comprehensive search of the Cochrane Library, Embase and MEDLINE databases was performed, covering studies from January 1900 to December 2023. To compare survival outcomes between synchronous and metachronous BM, hazard ratios (HRs) for overall survival (OS) were extracted from the included studies and pooled using a random-effects model. The systematic review included nine retrospective cohort studies comprising 910 patients with BM from CRC. Meta-analysis results showed no significant difference in OS between patients with synchronous and metachronous BM (HR, 0.90; 95% confidence interval, 0.59-1.38; P=0.63). In conclusion, this meta-analysis suggests that the timing of BM development does not impact OS in patients with BM from CRC.