A study found that aspirin lowers the risk of colorectal cancer recurrence. There are 1.9 million new colorectal cancer patients worldwide each year, and 30% to 40% experience recurrence even after surgery. The analysis suggests that aspirin, used as a pain reliever and fever reducer, also helps colorectal cancer patients.
A research team led by Professor Anna Martling at Sweden's Karolinska Institute said in the New England Journal of Medicine (NEJM) on the 17th (local time) that "after colorectal cancer surgery, taking 160 mg of aspirin once daily reduces the likelihood of recurrence."
The team randomly assigned 1,103 patients who had undergone colorectal cancer surgery in Sweden, Norway, Denmark, and Finland to receive either 160 mg of aspirin or a placebo for three years. All patients had PI3K gene mutations. PI3K is a gene associated with colorectal cancer recurrence. Earlier, the team genetically tested 2,980 colorectal cancer patients and categorized those with PI3K mutations.
The researchers used CT (computed tomography) and MRI (magnetic resonance imaging) scans to check for colorectal cancer recurrence. As a result, patients who took aspirin daily had a 55% lower risk of recurrence than those who took a placebo. The team judged that this was thanks to aspirin's suppression of platelet activity.
Platelets are a component of blood that aid coagulation. Cancer cells clump with platelets to evade attacks by immune cells. When a person takes aspirin, platelet function declines, making it harder for cancer cells to bind. That allows immune cells to attack cancer cells.
Aspirin is the first synthetic pharmaceutical, developed in 1897 by Dr. Felix Hoffmann at Germany's Bayer laboratory. Originally used as an analgesic and antipyretic, studies later found effects on hypertension, myocardial infarction, stroke, and cancer. However, aspirin's side effects also warrant caution.
In this study, 52 patients who took aspirin daily experienced serious side effects. Gastrointestinal bleeding, allergic reactions, and deep vein thrombosis were representative. Deep vein thrombosis is the formation of a blood clot in a deep vein. The researchers noted, "One death is presumed to be due to aspirin."
References
NEJM (2025), DOI: https://doi.org/10.1056/NEJMoa2504650