cisplatin + etoposide + S1

This is a combination chemotherapy regimen consisting of three agents: - **Cisplatin**: a platinum-based chemotherapeutic that forms DNA crosslinks, leading to apoptosis in rapidly dividing cells. - **Etoposide**: a topoisomerase II inhibitor that induces DNA strand breaks and prevents cell division. - **S1 (also written as S-1)**: an oral fluoropyrimidine derivative combining tegafur (a prodrug of 5-fluorouracil), gimeracil (a dihydropyrimidine dehydrogenase inhibitor), and oteracil (which reduces gastrointestinal toxicity). S1 inhibits thymidylate synthase, disrupting DNA synthesis. This combination is used experimentally or in clinical trials for various solid tumors, including lung cancer and gastric cancer. The regimen leverages the synergistic cytotoxic effects of these agents to improve antitumor efficacy. Each drug has a distinct mechanism targeting different aspects of tumor cell survival and proliferation.