• Posted September 18, 2025

Daily Aspirin Cuts Colon Cancer Recurrence Risk By Half

Aspirin can cut by more than half the risk that colon cancer will come back following initial treatment, a new clinical trial has found.

Daily aspirin reduced by 55% the risk of cancer recurrence in patients whose colorectal cancer is driven by a genetic mutation, researchers reported Sept. 17 in the New England Journal of Medicine.

“Aspirin is a drug that is readily available globally and extremely inexpensive compared to many modern cancer drugs, which is very positive,” lead researcher Anna Martling, a professor of molecular medicine and surgery at Karolinska Institute in Sweden, said in a news release.

The study focused on people whose colon cancer was driven by a mutation of the PIK3 gene, which helps regulate cell growth and division in the human body.

Every year, about 107,320 new cases of colon cancer and 46,950 cases of rectal cancer are diagnosed in the United States, according to the American Cancer Society.

Between 30% to 40% of colon cancer patients have their cancer come back and spread to other parts of the body following treatment, researchers said in background notes.

For the new study, researchers randomly assigned 626 colon cancer patients to take either a daily 160 mg dose of aspirin daily or a placebo pill for three years. The patients came from 33 hospitals in Sweden, Norway, Denmark and Finland.

All the patients had a PIK3 mutation, and all had undergone surgery to remove their cancer before starting aspirin.

“Aspirin is being tested here in a completely new context as a precision medicine treatment,” Martling said. “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.”

Researchers aren’t sure exactly why aspirin cuts the risk of cancer recurrence. They said it’s likely due to the drug’s ability to reduce inflammation, thin blood and subdue tumor cell growth.

All combined, these effects create an environment less favorable for cancer, researchers said.

“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,” Martling said.

More information

The American Cancer Society has more about genetic mutations and cancer.

SOURCES: The New England Journal of Medicine, Sept. 18, 2025; Karolinska Institute, news release, Sept. 17, 2025