Overview
- Pooling 10 randomized trials with about 124,837 average‑risk participants, the analysis focused largely on low doses of 75–100 mg daily.
- Aspirin did not lower colorectal cancer incidence within 5–15 years of use, with a possible benefit after 15 or more years rated as very uncertain and prone to confounding.
- Major extracranial bleeding increased by 59% and hemorrhagic stroke risk likely rose by about 40%, with harms appearing soon after starting therapy and higher in older people or those with ulcer or clotting disorders.
- The authors identified no suitable randomized trials of other NSAIDs, so the findings apply specifically to aspirin and may not extend to high‑risk groups.
- The study team and outside experts say the evidence does not support population‑wide aspirin prophylaxis and they prioritize established screening and lifestyle measures for prevention.