tislelizumab + 5-fluorouracil + cisplatin + radiotherapy

This is a combination regimen comprising **tislelizumab**, **5-fluorouracil**, **cisplatin**, and **radiotherapy** used primarily in the treatment of cancers such as esophageal squamous cell carcinoma and gastric/gastroesophageal junction cancers. Tislelizumab is a humanized IgG4 monoclonal antibody that targets the programmed cell death protein 1 (PD-1) receptor on T cells, acting as an immune checkpoint inhibitor and restoring T-cell mediated antitumor responses. 5-fluorouracil and cisplatin are cytotoxic chemotherapeutic agents: 5-fluorouracil inhibits thymidylate synthase, disrupting DNA synthesis, while cisplatin causes DNA crosslinking and apoptosis. Radiotherapy uses ionizing radiation to further induce tumor cell death. This combination leverages immune checkpoint blockade, cytotoxic chemotherapy, and localized anticancer effects from radiotherapy to improve treatment outcomes, particularly in advanced-stage or unresectable cancers. The regimen is commonly investigated in and used for solid tumors of the upper gastrointestinal tract, notably in clinical trials for esophageal and gastric cancers[1][2][3][4][5].