Anna Martling. Poto: Liza Simonsson
The current study included more than 3,500 patients with colon and rectal cancer from 33 hospitals in Sweden, Norway, Denmark, and Finland. Patients whose tumors showed a specific genetic mutation in the PIK3 signaling pathway—a mutation found in approximately 40 percent of patients—were randomized to receive either 160 mg of aspirin daily or a placebo for three years after surgery.
For patients with the genetic mutation in PIK3, the risk of recurrence was reduced by 55 percent in those who received aspirin 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.
Less favorable environment for cancer
So how does aspirin reduce the risk of recurrence of colon and rectal cancer? The researchers believe that the effect is likely due to aspirin acting through several parallel mechanisms – it reduces inflammation, inhibits platelet function and tumor growth. This combination makes the environment less favorable for cancer.
“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.
The researchers believe that the results could have global significance and influence treatment guidelines for colon and rectal cancer worldwide. Anna Martling sees the fact that the drug is well established as a major advantage.
“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 was funded in part by The Swedish Research Council, the Cancer Foundation, and Radiumhemmets forskningsfonder. The researchers state that there are no conflicts of interest.
Publication
”Low-Dose Aspirin for PI3K-Altered Localized Colorectal Cancer”, Anna Martling, Ida Hed Myrberg, Mef Nilbert, Henrik Grönberg, Fredrik Granath, Martin Eklund, Tom Öresland, Lene H. Iversen, Carola Haapamäki, Martin Janson, Karin Westberg, Josefin Segelman, Urban Ersson, Mattias Prytz, Eva Angenete, Rebecka Bergström, Markus Mayrhofer, Bengt Glimelius, Johan Lindberg, The New England Journal of Medicine, online September 17, 2025, doi: NEJMoa2504650.