Key Takeaway
Regular aspirin use for 6+ years was associated with 19% lower risk of colorectal cancer and 15% lower overall cancer risk.
Summary
This large prospective cohort study examined the association between long-term aspirin use and cancer incidence using data from the Nurses' Health Study and Health Professionals Follow-up Study.
Study Population:
- 135,965 participants
- Follow-up: Up to 32 years
- 88,084 women and 47,881 men
Key Findings:
Overall Cancer Risk:
- Regular aspirin use (≥2 tablets/week) for 6+ years: 3% lower total cancer incidence
- Most benefit seen after 6 years of continuous use
- Benefit persisted after stopping aspirin
Colorectal Cancer:
- 19% reduction in colorectal cancer risk with regular use
- Strongest effect seen with doses of 0.5-1.5 standard aspirin tablets/day
- Benefit appeared after ~6 years of use
Gastrointestinal Cancers:
- 15% reduction in overall GI tract cancers
- Effects seen for esophageal, stomach, and colorectal cancers
Population Impact:
- If all US adults 50-64 took aspirin, an estimated 29,800 fewer GI cancers would occur over 10 years
- This must be balanced against approximately 5,400 excess GI bleeding events
Conclusions:
Long-term aspirin use is associated with meaningful reductions in cancer risk, particularly colorectal cancer. However, benefits take years to emerge and must be weighed against bleeding risks.