bevacizumab + folinic acid + fluorouracil + irinotecan + yttrium-90

This is a multi-agent combination regimen consisting of five components: - **Bevacizumab** is a monoclonal antibody that inhibits vascular endothelial growth factor A (VEGF-A), thereby blocking angiogenesis, the process by which tumors develop new blood vessels. - **Folinic acid** (also known as leucovorin or calcium folinate) is not itself cytotoxic but enhances the effectiveness of fluorouracil by stabilizing its binding to thymidylate synthase. - **Fluorouracil** (5-FU) is an antimetabolite chemotherapy agent that inhibits thymidylate synthase, disrupting DNA synthesis and leading to cell death in rapidly dividing cells. - **Irinotecan** is a topoisomerase I inhibitor that prevents DNA from unwinding, resulting in DNA damage and apoptosis in cancer cells. - **Yttrium-90** is a radioactive isotope used for selective internal radiation therapy (SIRT), typically delivered via microspheres directly into liver tumors. It emits beta radiation to locally destroy tumor tissue. This combination targets metastatic colorectal cancer, especially with liver involvement. The regimen combines systemic chemotherapy and targeted antiangiogenic therapy with regional radiopharmaceutical treatment for enhanced local control.