Doctors stunned by a cheap drug’s power against colon cancer

Every year, almost two million people around the world are diagnosed with colorectal cancer. Up to 40 percent eventually develop metastases, which makes treatment much more difficult and significantly lowers survival rates.

Exploring Aspirin's Role in Cancer Recurrence

Earlier observational research hinted that aspirin might lower the risk of some cancers and could help prevent recurrence in colorectal cancer patients who have mutations in genes connected to the PIK3 signaling pathway. These genes are crucial for regulating cell growth and division.

When mutations occur, these processes can lose control, allowing cells to multiply abnormally and form tumors. Until now, evidence from previous studies was inconsistent, and no randomized clinical trial had confirmed whether aspirin truly made a difference. To fill that gap, researchers launched the large-scale ALASCCA trial, now published in The New England Journal of Medicine.

The ALASCCA Trial: A Landmark Study

The study involved more than 3,500 colon and rectal cancer patients across 33 hospitals in Sweden, Norway, Denmark, and Finland. Participants whose tumors carried a particular PIK3 pathway mutation (found in roughly 40 percent of all cases) were randomly assigned to receive either 160 mg of aspirin per day or a placebo for three years after surgery.

For those with the genetic mutation, aspirin reduced the risk of the cancer returning by an impressive 55 percent compared with the placebo group.

"Aspirin is being tested here in a completely new context as a precision medicine treatment. This is a clear example of how we can use genetic information to personalize treatment and at the same time save both resources and suffering," says first author Anna Martling, professor at the Department of Molecular Medicine and Surgery, Karolinska Institutet, and senior consultant surgeon at Karolinska University Hospital.

How Aspirin May Work Against Cancer

Researchers suggest that aspirin's protective effect likely comes from multiple biological mechanisms. The drug is known to reduce inflammation, limit platelet activity, and inhibit tumor growth. Together, these effects make the body less hospitable to cancer recurrence.

"Although we do not yet fully understand all the molecular links, the findings strongly support the biological rationale and suggest that the treatment may be particularly effective in genetically defined subgroups of patients," says Anna Martling.

According to the research team, these findings could influence colon and rectal cancer treatment strategies around the world. Martling emphasizes that one of aspirin's greatest advantages is its accessibility.

"Aspirin is a drug that is readily available globally and extremely inexpensive compared to many modern cancer drugs, which is very positive," says Anna Martling.

The study received partial funding from the Swedish Research Council and the Swedish Cancer Society. The researchers report no conflicts of interest.

Facts: What is aspirin?

Aspirin contains acetylsalicylic acid, a compound that reduces pain, fever, and inflammation. It belongs to a group of medicines called NSAIDs (non-steroidal anti-inflammatory drugs). The effects typically begin within about 30 minutes. In lower doses, aspirin is often used to prevent blood clots.

Common side effects include stomach discomfort and an increased risk of bleeding. People with stomach ulcers, bleeding disorders, or asthma should avoid aspirin. Although higher doses can be purchased over the counter, it should be taken cautiously, especially when combined with other blood-thinning medications or alcohol.