Answer: Metformin, mebendazole, niclosamide, and doxycycline are not established or recommended treatments for stage 4 colon cancer according to UK clinical guidelines and licensed therapies. The standard treatment for metastatic (stage 4) colorectal cancer involves systemic anti-cancer therapies such as chemotherapy regimens including oxaliplatin combined with fluoropyrimidines (e.g., 5-fluorouracil or capecitabine), targeted agents, and other licensed drugs like trifluridine/tipiracil. Surgical options and multidisciplinary management are also considered depending on metastasis sites and patient condition SmPC Oxaliplatin,SmPC Trifluridine/Tipi,SmPC Capecitabine,SmPC Capecitabine,NICE NG151.
Explanation: None of the provided guidelines or summary of medicinal product characteristics mention metformin, mebendazole, niclosamide, or doxycycline as treatments for colon cancer. In contrast, licensed chemotherapies such as oxaliplatin combined with 5-FU and folinic acid, capecitabine (alone or with oxaliplatin), and trifluridine/tipiracil are recommended for treating metastatic colorectal cancer, including stage 4 disease SmPC Oxaliplatin,SmPC Trifluridine/Tipi,SmPC Capecitabine,SmPC Capecitabine,NICE NG151. NICE NG151 guidelines emphasize systemic anti-cancer therapies and multidisciplinary team involvement for metastatic colorectal cancer management, with no inclusion of the queried agents NICE NG151.