A major Swedish trial has found that a daily low dose of aspirin can cut the risk of colorectal cancer returning after surgery by more than half in patients with specific genetic mutations.
The Alascca trial, led by Prof Anna Martling at the Karolinska Institute, tested more than 3,500 patients across Scandinavia. Genetic analysis showed that about 37% carried mutations in the PI3K pathway, making them more responsive to aspirin’s effects. Those who received 160mg of aspirin daily were 55% less likely to see their cancer return compared with those on placebo.
Martling said the findings could change clinical practice, stressing the need for routine genetic testing so patients with the mutations can access the inexpensive drug. Aspirin appears to work by reducing inflammation, interfering with the PI3K pathway, and preventing blood platelets from shielding cancer cells from the immune system.
While the results are promising, long-term aspirin use carries risks. In the trial, four patients experienced severe adverse events possibly linked to aspirin, including gastrointestinal bleeding and a fatal brain hemorrhage. Researchers emphasized the importance of weighing benefits against risks.
Experts, including Cancer Research UK, welcomed the study and called for further large-scale trials to identify which patients could benefit most from aspirin therapy.
