Introduction
Cancer and stroke are two leading causes of morbidity and mortality worldwide. Owing to the hypercoagulability state, tumor compression of blood vessels, and treatment-related effects, cancer patients are at high risk of stroke. Few studies have suggested that d-dimer might act as a biomarker for Cancer-Related Stroke (CRS).

Method
A computer literature search of PubMed was conducted to identify relevant studies till March 2018. The association between d-dimer levels and CRS was pooled as odds ratio (OR) while the association between d-dimer levels and mortality was pooled as hazard ratio (HR). Data of the d-dimer levels in cancer patients with stroke compared to those without stroke were pooled as weighted mean difference (WMD) between the two groups in a random effect model meta-analysis.  

Results
Twenty-three studies were included in the final analysis. D-dimer was significantly associated with the occurrence of CRS (OR 1.34, 95%CI [1.28 to 1.40]). The levels of d-dimer were higher in cancer patients with stroke compared to those without stroke (WMD 0.16, 95% CI [0.14 to 0.19]). Moreover, d-dimer levels were significantly higher in cancer patients with cryptogenic stroke compared to cancer patients with conventional stroke (WMD 0.68, 95% CI [0.45 to 0.91]). In terms of stroke outcome, d-dimer was a significant predictor of mortality (HR 2.21, 95% CI [1.75 to 2.80]).

Conclusion
High d-dimer levels were associated with CRS. In cancer patients, d-dimer levels were higher in cryptogenic stroke compared to conventional stroke and could significantly predict mortality after stroke in patients with active cancer.

D-DIMER AS A PROGNOSTIC MARKER AND AN INDICATOR OF OCCURRENCE OF CANCER-RELATED STROKE IN PATIENTS WITH ACTIVE CANCER – A META-ANALYSIS