Efficacy of regorafenib in acute pulmonary carcinomatous lymphangitis as a manifestation of rectal cancer: A case report.

Recent therapeutic advancements have prolonged the survival duration of patients with metastatic or recurrent colorectal cancer even during salvage treatment. Although treatment with regorafenib and trifluridine/tipiracil combination has exhibited apparent survival benefits, clear and objective evidence of a response to these drugs is scarce. Herein, the present study reports the case of a patient with rectal cancer refractory to multiple surgical interventions and standard chemotherapy. Treatment with regorafenib resulted in immediate improvement of respiratory failure caused by pulmonary lymphangitic carcinomatosis. This improvement persisted for over 3 months and was confirmed by radiology. Our findings suggest that regorafenib can reduce peritumoral edema via its interaction with the vascular endothelial growth factor receptor. Thus, regorafenib functions as a multityrosine kinase inhibitor to alleviate symptoms of lymphangitic carcinomatosis despite the low potency of the drug.