Aspirin and colorectal cancer: A daily low dose of aspirin cut the risk of colorectal cancer returning by about half in patients whose tumours harboured PI3K-pathway mutations, according to results of the ALASCCA trial led by Sweden’s Karolinska Institute and published in the New England Journal of Medicine.
The randomised study screened 3,500+ postsurgery patients across Sweden, Norway, Denmark, and Finland; genetic testing of 2,980 participants found 1,103 (≈37%) carried PI3K-related mutations. Those mutation-positive patients were assigned to 160 mg aspirin or a placebo once daily for three years. Recurrence was 55% lower in the aspirin group than in the placebo, a magnitude Prof. Anna Martling called “practice-changing.” About 40% of colorectal cancers are thought to feature such mutations.
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Researchers suggest aspirin’s benefit stems from dampening inflammation, interfering with PI3K signalling, and inhibiting platelet activity that can shield tumour cells from immune attack. Martling said the findings support routine genomic testing in colorectal cancers to identify candidates for adjuvant aspirin.
Safety signals were consistent with known risks of long-term aspirin use: four severe adverse events potentially linked to the drug (including gastrointestinal and intracranial bleeding and an allergic reaction) were reported; four deaths occurred overall, with one possibly aspirin-related.
Colorectal cancer diagnoses approach 2 million annually worldwide and are rising in people under 50. Prior studies have shown chemopreventive effects of aspirin in high-risk hereditary groups (e.g., Lynch syndrome).
