streptozocin + doxorubicin + fluorouracil + cisplatin

This regimen is a **non-branded combination chemotherapy protocol** comprising four cytotoxic agents: **streptozocin**, **doxorubicin**, **fluorouracil (5-FU)**, and **cisplatin**. Each agent has a distinct mechanism of action: - **Streptozocin** is a nitrosourea antibiotic that alkylates DNA, exhibiting a selective cytotoxic effect on pancreatic beta cells and showing significant activity in neuroendocrine tumors. - **Doxorubicin** is an anthracycline antineoplastic that intercalates into DNA, inhibiting topoisomerase II and inducing cytotoxic free radicals. - **Fluorouracil (5-FU)** is a pyrimidine antimetabolite that inhibits thymidylate synthase, thus blocking DNA synthesis. - **Cisplatin** is a platinum-based compound that forms DNA cross-links, inhibiting DNA replication and transcription. This 4-drug regimen is considered a **non-standard, investigational regimen** typically explored in advanced, refractory cancers (notably pancreatic neuroendocrine tumors and carcinomas) when escalated cytotoxicity is desired. It is related to but more intensive than the established 3-drug FAS regimen (**fluorouracil + doxorubicin + streptozocin**), which is used for advanced pancreatic neuroendocrine tumors[5][7][9][13]. Combination with cisplatin may be based on extrapolation from regimens containing cisplatin with 5-FU and other agents, used in various advanced cancers, but supporting clinical trial evidence for this precise quadruplet is sparse.