Patients with cancer and people with blood types other than I face an increased risk of venous thromboembolism (VTE) 3 months after surgery, new study published in the journal Blood Advances reports.

VTE includes deep vein thrombosis (DVT), in which a clot forms in the deep veins of the legs, and pulmonary embolism (PE), a life-threatening condition in which the clot breaks away from the vessel wall and gets stuck in the arteries of the lung.

Although anyone can experience thrombosis, existing studies show that people with blood types other than I have an increased risk of developing blood clots. Cancer and cancer treatments also increase the risk of blood clots.

The study authors collected data from 1,708 adults with a new or recurrent cancer diagnosis. The scientists grouped them first by blood type and then classified them by tumor type. Although tumor type may be helpful in identifying people who are more likely to develop VTE, many people with less severe tumors still have dangerous blood clots and may therefore need additional monitoring and treatment.