Early angiographic changes after hemostatic radiotherapy for gastric cancer bleeding, mentioning the mechanism and potential immediate effects of the treatment.

Although hemostatic radiotherapy has been reported as an effective treatment for gastric cancer bleeding, its mechanism and immediate effects remain unclear. We experienced a case of gastric cancer bleeding originating from both the whole gastric tumor and a left gastric arterial pseudoaneurysm at the tumor-associated ulcer. The patient was treated with radiotherapy for bleeding from the whole gastric tumor, followed by transcatheter arterial embolization for the left gastric arterial pseudoaneurysm. Angiography performed two hours after radiotherapy with an X-ray of 8 Gy in a single fraction revealed the disappearance of both tumor vessels and tumor stain from not only the embolized left gastric artery but also both the non-embolized right gastric artery and common trunk of the left gastric and the left hepatic arteries, which indicated these angiographic changes of the non-embolized arteries were presumed to reflect an immediate effect of hemostatic radiotherapy. Following hemostatic treatments, the patient's vital signs stabilized, and hemoglobin levels did not decrease, indicating immediate hemostasis. This case suggests a link between hemostatic mechanism and early tumor vessel changes, indicating that hemostatic radiotherapy can achieve rapid bleeding control. Therefore, hemostatic radiotherapy should be considered an emergency treatment option for gastric cancer bleeding.