4 cases that various thrombosis developed in during head and neck cancer treatment

Because malignant tumor cells cause the production of blood coagulation agent and activation of plateletinduced agglutination, cancer patients are in a state of hypercoagulability and easily develop thrombosis. We report four cases who developed thrombosis during treatment for head and neck cancer. In two cases, clots formed in lower limb arteries; in the other two cases, clots formed in the pulmonary artery and brachial vein. Two cases recovered and remain alive now, but two cases died suddenly within a few days from the onset of thrombosis. There are various types of patients with thrombosis, and the treatment and severity differ accordingly. However, cases that develop thrombosis are forced to discontinue cancer treatment and may die suddenly. Since it is predicted that the number of patients with cancer who survive for a long time will increase in the future, greater awareness of thrombosis as a disease state is needed.