Does Aspirin Protect Against Colorectal Cancer?

Authors of a recent review concluded that long-term follow-up from randomized controlled trials provides strong evidence of the chemoprotective effect of aspirin for colorectal cancer (CRC) among high-risk groups, including patients with Lynch syndrome.

However, they added, “Observational cohort studies consistently demonstrate a modest, time-dependent reduction in CRC incidence with prolonged ASA use. However, the optimal dosing strategy remains unresolved, as existing studies vary in dosage levels without identifying a universally superior regimen.”

Randomized trials of aspirin for secondary prevention in unselected populations have not shown a consistent survival or recurrence benefit. Yet, stratified analyses suggest a marked advantage in patients with tumors harboring mutations in the Phosphatidylinositol-4,5-Bisphosphate 3-Kinase Catalytic Subunit Alpha (PIK3CA) gene.

The heterogeneity of findings highlights the importance of refining patient selection and developing biomarker-driven strategies.

Key unanswered questions include determining the optimal dose, treatment duration, and long-term safety profile in different patient populations. Current research emphasizes biomarker-guided prevention, with ongoing trials aiming to clarify the role of aspirin in both sporadic and hereditary CRC.

“Ongoing research on dosage optimization and biomarker-driven selection is expected to further refine the integration of ASA into standard CRC prevention strategies,” the authors concluded.

Reference

Genoud V, Kim F, Koessler T. Aspirin for colorectal cancer chemoprevention: where are we? Curr Opin Oncol. 2025;37(4):383-390. doi:10.1097/CCO.0000000000001153.