Rectal ulcer associated with lenvatinib 15 years after definitive radiotherapy for prostate cancer: A case report

Lenvatinib is a multi-kinase inhibitor that blocks vascular endothelial growth factor, fibroblast growth factor and platelet-derived growth factor receptors. The present study describes a case of rectal ulceration triggered by lenvatinib treatment for hepatocellular carcinoma 15 years after definitive radiotherapy for prostate cancer. A 58-year-old man underwent definitive external beam radiotherapy and high-dose-rate brachytherapy for prostate cancer. A total of 15 years after radiotherapy for prostate cancer, the patient was diagnosed with hepatocellular carcinoma with multiple metastases. Treatment with 12 mg/day lenvatinib was commenced. A total of 4 months after starting lenvatinib therapy, the patient experienced persistent anal pain with a deep ulceration of the anterior wall of the lower rectum. As the pain did not improve, the patient chose to undergo a colostomy, resulting in the resolution of the anorectal pain. To the best of our knowledge, the present case report is the first to report on lenvatinib-induced rectal ulcers after radiotherapy.