For many decades, aspirin has been a staple in every household—relieving pain and fever, while also being recognized for its cardioprotective properties. Now, scientists are discovering another remarkable benefit: its ability to reduce the risk of certain types of cancer.

A personal story sparks scientific hope
Nick James, a British furniture maker, saw his mother die from cancer and many members of his family also diagnosed with the disease. He underwent genetic testing, which showed, according to the BBC, that he carried a mutation associated with Lynch syndrome—a condition that dramatically increases the risk of colorectal cancer.

Seeking options, James participated in a clinical trial led by John Burn at the University of Newcastle. The aim of the study was to determine whether a daily dose of aspirin could help prevent cancer in high-risk individuals. More than a decade later, James has not developed cancer, reinforcing the potential protective properties of aspirin.

Accumulated evidence from clinical trials
Aspirin was developed in the 19th century. Initially used for pain relief, its benefits soon expanded to include cardiovascular protection, as it reduces blood clotting by making platelets less sticky. By the 1970s, researchers began to suspect it might also affect cancer. Early animal studies suggested it could slow or prevent metastasis, but its effects in humans remained uncertain.

In recent years, large-scale studies have explored the issue. A trial led by Burn followed 861 patients with Lynch syndrome over a decade. The results were striking: those who took daily aspirin for at least two years reduced their risk of developing colorectal cancer by about 50%. Even more encouraging is that, according to newer findings, lower doses—similar to those used for heart disease prevention—may offer comparable benefits with fewer side effects.

Meanwhile, Anna Martling from the Karolinska Institute investigated aspirin’s role in preventing cancer recurrence. Her study, involving nearly 3,000 colorectal cancer patients, found that aspirin reduced the risk of recurrence by more than 50% in individuals with specific genetic mutations.

These findings have already influenced many healthcare systems. In Sweden, patients with certain tumor mutations take aspirin as part of their treatment plan. Similarly, UK guidelines recommend aspirin for individuals with Lynch syndrome under medical supervision.

How aspirin may fight cancer
Researchers believe it works through multiple pathways:

• Reducing inflammation: Aspirin inhibits the COX-2 enzyme, which produces prostaglandins—molecules that promote tumor growth.
• Limiting cellular damage: By reducing inflammation, aspirin may limit the conditions that allow cancer cells to develop.
• Enhancing immune response: Research led by Rahul Roychoudhuri at the University of Cambridge suggests that aspirin may help the immune system detect and destroy cancer cells by inhibiting thromboxane A2, a clotting factor that protects tumors from immune attack.

A promising tool—with important limitations
Given these benefits, it may be tempting to view aspirin as a universal preventive solution. However, experts warn that aspirin can cause side effects, such as stomach ulcers, internal bleeding, and, in rare cases, brain hemorrhage. For this reason, most researchers recommend its use only for specific high-risk groups and always under medical supervision.

With each new study, scientists uncover deeper insights into aspirin’s protective and therapeutic properties. Although it is not a cure-all, it may in the future become an increasingly important part of cancer prevention strategies for those at highest risk.