Aspirin May Prevent Colorectal Cancer Recurrence, Study Finds

By Adebowale Bello. B.Tech Microbiology, Freelance Health Writer. Medically reviewed by the DLHA team.

December 3, 2025.

Aspirin tablets in an open container

Colorectal cancer is among the most common cancers globally and its impact is rising globally including in many African countries. A 2022 report estimated more than 70,000 new cases and about 46,000 deaths occurred across the continent, showing how serious the burden has become. This growing trend has pushed researchers to look into whether everyday medicines such as aspirin can help reduce the chances of the disease returning after treatment.

A new study now suggests that low dose aspirin may offer real benefits, although only for a particular group of patients.

About the Study

The study was a large clinical trial carried out in Sweden, Norway, Denmark and Finland. More than 3,500 patients underwent surgery for colorectal cancer and after an eligibility review, 626 patients who had complete genomic data were selected for the study. The researchers wanted to find out whether giving low dose aspirin every day for three years could reduce the risk of the cancer returning.

The researchers focused on a type of genetic change known as a PI3K pathway alteration. Some colorectal cancers have this alteration while others do not. The PI3K pathway affects how cells grow and divide so when it is altered it can help cancer cells survive. Earlier studies had suggested that aspirin may work better in patients with this specific alteration.

Patients were randomly assigned to take low dose aspirin or a placebo. A placebo looks like a real medicine but has no active ingredient. This type of randomised design allows researchers to compare the effects of aspirin fairly because neither the patients nor the doctors know who is receiving the real medicine.

What the Study Found

The study found that low dose aspirin reduced the risk of colorectal cancer coming back but this benefit was seen mainly in patients whose tumours had the PI3K alteration. In those patients the chance of the cancer returning was lowered by about half compared with those who took the placebo. For patients whose tumours did not have the alteration, aspirin did not make a meaningful difference.

Aspirin is known for reducing inflammation and preventing blood clots and the researchers believe that in patients with the PI3K alteration aspirin may interfere with the biological environment that supports tumour growth. This creates a less favourable setting for cancer cells to return after surgery.

Although aspirin is inexpensive and widely available the study still used a controlled dose of around 160 milligrams per day. It was given consistently for three years and participants were monitored for side effects.

Limitations of the Study

Although the study is well designed, it has limitations. 

1. The trial was done entirely in Nordic countries so the results may not fully apply to African populations. Factors such as genetics, diet, microbiome differences and access to healthcare could influence how aspirin works.

2. The benefit was seen only in patients with the PI3K alteration which means many patients will not benefit. Screening for this alteration requires laboratory capacity which may not be readily available in most African hospitals.

3. The researchers did not focus heavily on long term survival beyond recurrence. It is still important to know whether aspirin helps patients live longer or only delays recurrence. Longer follow up is needed.

4. Aspirin also has clear risks such as stomach bleeding and in rare cases, bleeding in the brain. These risks may be higher in people with untreated ulcers, heavy alcohol use or other health conditions.

What the Study Means for Africans

There are several lessons for Africans from this research.

First, it shows the growing importance of precision medicine. Not every medicine works for every patient. What works for one person may not work for another and this study clearly shows that aspirin is helpful only for a specific genetic subgroup of colorectal cancer patients. This means African health systems need to strengthen access to diagnostic tools that can identify genetic changes in tumours. At the moment, many cancer care centres across the continent lack the equipment to perform molecular testing.

Second, the study highlights the need for better cancer surveillance and early detection. African countries are already seeing a rise in colorectal cancer especially among younger people. If more patients can be diagnosed early and undergo surgery then treatments that prevent recurrence become more relevant.

Third, although aspirin is cheap and easy to obtain, people should never self-medicate for cancer prevention or cancer treatment. Aspirin can cause serious side effects especially stomach bleeding and it interacts with many other medicines. Patients must use it only under medical guidance. This is important because over the counter abuse of medicines is common in many African communities.

Lastly, the results may help shape future cancer guidelines in African oncology centres once more studies confirm the findings in more diverse populations. The Nordic populations in the study differ genetically and environmentally from African populations which means results may not always be identical.

Wrap Up

This new study offers promising evidence that low dose aspirin can reduce the risk of colorectal cancer recurring after surgery but only in patients whose tumours have the PI3K alteration. It adds to growing research showing that cancer treatment is becoming more personalised.

For Africans the findings highlight the need for better diagnostic services, stronger cancer care systems and greater awareness of early detection. Aspirin remains a valuable medicine but it must be used safely and only under medical supervision. As more research emerges health professionals will be better placed to decide how to use this information to improve cancer outcomes across the continent.

Source: Martling A, Myrberg IH, Nilbert M, Grönberg H, Granath F, Eklund M, Öresland T, et al. Low dose aspirin for PI3K altered localised colorectal cancer. The New England Journal of Medicine, 2025;393(11), 1051–1064. Available from here 

Related:

Regular Daily Aspirin Use May Prevent Colon Cancer; Research suggests

Colorectal Cancer in Africa: A Fact-sheet

Published: December 3, 2025

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