Cancer patients' blood type might play a role in their risk for dangerous blood clots, researchers say.
Cancer and its treatments increase the risk for venous thromboembolism (VTE). That includes deep-vein thrombosis (DVT, a blood clot that typically forms in the deep veins of the leg) and pulmonary embolism (PE, a life-threatening condition that occurs when a blood clot breaks free and travels to the lungs' arteries).
VTE is the leading cause of preventable hospital deaths in the United States.
Factors such as tumor or cancer type are now used to identify cancer patients at high risk of VTE, but many go unidentified. This study concluded that cancer patients with non-O blood types, such as types A, B and AB, are at increased risk for VTE.
"We've known tumor type helps determine the baseline risk for VTE," said study author Cornelia Englisch, a doctoral student at the Medical University of Vienna. "But we continue to see that these risk assessments fail to capture all cancer patients who develop these blood clots. By solely assessing tumor type, we miss up to 50% of people who develop VTE."
The findings from an analysis of data from more than 1,700 people in Austria with a new or recurrent cancer diagnosis were published April 13 in the journal Blood Advances.
The researchers reported that cancer patients with non-O blood types were more likely to develop VTE three months after their diagnosis or cancer recurrence.
Englisch said the increased risk is not apparent at the time of diagnosis, because cancer therapies increase the odds of developing blood clots.
The investigators also found that patients with non-O blood types and tumors outside the high-risk disease category were more likely to develop clots. This shows that relying solely on tumor type to assess VTE risk may miss many at-risk patients.
Further research is needed before blood typing might prove useful in assessing cancer patients' VTE risk.
"Blood typing is easy to perform, can be done worldwide, and doesn't require any specialized background knowledge or equipment," Englisch said in a journal news release.
"And of course, every risk factor that we identify helps us to understand these life-threatening complications in cancer patients better," she added. "Perhaps this will create awareness for the role blood types can play as clinical biomarkers."
The new study follows another, published last year, that examined treatment of cancer-related VTE.
The U.S. National Heart, Lung, and Blood Institute has more about VTE.