LAUSR

INTRODUCTION Previous studies have shown that simultaneous treatment with sorafenib, a vascular endothelial growth factor receptor tyrosine-kinase inhibitor (VEGFR-TKI), and radiation therapy (RT) can cause gastrointestinal hemorrhage (GH) as an adverse event. However, it is known that sorafenib monotherapy can cause GH. Thus it is essential to know the association between the radiation field and the bleeding site. CASE PRESENTATION We report a case of bleeding ulcers on the ascending colon in a patient undergoing simultaneous RT and sorafenib administration. Two clips were placed at the proximal and distal ends of the ulcer lesions and the relevance to the radiation field was evaluated using computed tomography images. We observed that the sites of the bleeding ulcers corresponded with radiation dose distribution. In addition, we report on intramuscular bleeding corresponding with radiation dose distribution, which has not been previously reported on. CONCLUSIONS The administration of sorafenib during RT can lead to intestinal and intramuscular bleeding. Therefore, the risk of bleeding from organs exposed to RT must be taken into account when RT and VEGFR-TKI administration occurs simultaneously or in succession.