This information is for educational purposes only. Off-label drug use carries risks. Always consult a qualified physician before using any drug outside its approved indication.
Aspirin
Acetylsalicylic Acid
Brand names: Aspirin, Bayer, Ecotrin
ORIGINALLY APPROVED FOR
Pain Relief, Fever, Anti-platelet (cardiovascular)
Aspirin is one of the most robustly studied repurposed drugs in cancer prevention. Multiple large prospective cohort studies (including the landmark Nurses' Health Study and ASPREE trial) show regular low-dose aspirin reduces colorectal cancer incidence by 20–40% and may reduce risk of gastric, oesophageal, breast, and ovarian cancers. Its mechanism is primarily COX-2 inhibition, which reduces prostaglandin E2 — a key driver of tumour inflammation, angiogenesis, and immune evasion.
Molecular Pathways Targeted
Mechanism of Action in Cancer
Irreversibly inhibits COX-1 and COX-2 enzymes → reduces prostaglandin E2 (PGE2) synthesis → decreases tumour inflammation, angiogenesis, and immune evasion. Also inhibits NF-κB transcription factor, reduces platelet-derived growth factors that feed tumours, and activates NRF2 antioxidant response.
Cancers Studied
Typical Off-Label Dosing
75–325 mg daily (low-dose aspirin). Most cancer prevention studies used 75–100 mg. Higher doses used in some protocols but carry higher GI bleeding risk. Often taken at bedtime to align with platelet production cycle.
* Dosing information from research literature only. Not a prescription. Requires physician supervision.
Cautions & Drug Interactions
- Increases risk of GI bleeding — use with proton pump inhibitor if history of ulcers
- Contraindicated in aspirin-sensitive asthma
- Avoid in children under 16 (Reye's syndrome risk)
- Stop 7–10 days before surgery
- Not recommended for cancer treatment without physician supervision
- Risk of haemorrhagic stroke at higher doses in elderly