Routine tests flag up cancer danger in cryptogenic stroke

By Eleanor McDermid, Senior medwireNews Reporter

Blood tests and imaging findings could point to hidden malignancies in patients with cryptogenic stroke, say researchers.

Stroke patients with occult cancer have elevated D-dimer levels and frequently have multiple infarcts in multiple territories, report Oh Young Bang (Sungkyunkwan University School of Medicine, Seoul, Korea) and colleagues.

The team notes that multiple infarcts in multiple territories is not unique to patients with cancer-related stroke, as the same pattern can result from cardiogenic, paradoxical, and aortogenic embolic strokes. But, in all, 76.1% of 71 patients with active cancer at the time of stroke had multiple lesions in multiple territories, compared with just 17.3% of 277 patients without known cancer.

And together with D-dimer levels above 2.15 µg/mL, this feature was 73.8% sensitive and 96.6% specific for the presence of cancer, with positive and negative predictive values of 87.3% and 92.1%, respectively.

There were 22 patients in the cancer-free group who had D-dimer levels above the identified cutoff, and 10 of these patients had multiple lesions in multiple territories. When these 10 patients were examined further, they all proved to have occult malignancies, Bang et al report in PLoS ONE.

Moving these patients into the cancer-related-stroke group further strengthened the association of D-dimer levels and imaging patterns with cancer, with the sensitivity and specificity improving to 85.7% and 96.6%, respectively, and the positive and negative predictive values improving to 88.9% and 95.5%, respectively.

"Clinicians should suspect occult cancer when they diagnose ischemic stroke involving multiple vascular territories with high D-dimer levels and without identifiable causes of stroke or elevated D-dimer," say the researchers.

Average D-dimer levels were 10.67 µg/mL in the active cancer group versus 0.45 µg/mL in the cancer-free group, which Bang and team say implicates hypercoagulopathy in the pathogenesis of cancer-related stroke.

However, D-dimer levels were low in a comparison group of 33 lung cancer patients without stroke, at 0.67 µg/mL, which they say suggests that other triggering factors are needed for hypercoagulopathy and stroke to occur.

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