497P - Does the primary location and metastatic timing of colorectal cancer influence the survival of patients with brain metastasis? A meta-analysis

Background

The primary site of colorectal cancer (CRC) influences survival outcomes when metastasized to the liver or lung, with left-sided CRC being associated with longer survival than right-sided CRC. Additionally, the timing of metastasis, whether synchronous or metachronous, has been suggested as a factor for survival, with synchronous metastasis generally considered more aggressive than metachronous CRC with brain metastasis (BM). We investigated the effect of both CRC’s primary location and metastatic timing on overall survival (OS) upon metastasis to the brain.

Methods

We systematically searched PubMed, Embase, and the Cochrane Library. We included studies that described patients diagnosed with BM from CRC, with reports on survival outcomes based on different primary tumor sites (left vs right) or metastatic timing (synchronous vs metachronous). Within the eligible studies, we extracted hazard ratios (HR) for OS and conducted a meta-analysis by using the random-effect model.

Results

Out of 5836 studies identified through our search, 7 studies met the inclusion criteria for the meta-analysis. Similar to lung and liver metastasis of CRC, left-sided primary CRC exhibits better OS than right-sided CRC (multivariate HR = 0.71, 95% CI: 0.54-0.94, univariate HR = 0.75, 95% CI: 0.57-0.99) when metastasized to the brain. Regarding the timing of metastasis, we found no significant difference in OS between synchronous and metachronous metastasis (HR = 0.83, 95% CI: 0.48-1.43). Table: 497P

Hazard ratio of the included studies

Abbreviations: HR, hazard ratio; CI, confidence interval

Conclusions

Left-sided colon cancer exhibited higher OS compared to right-sided colon cancer, consistent with findings in lung and liver metastasis. However, OS did not differ between synchronous and metachronous metastasis. Further studies comparing the genotypes and mutations of CRC with BM based on their primary location and metastatic timing are warranted.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.