A daily aspirin is not a quick or reliable solution for preventing colon cancer in the general population and carries immediate risks of serious bleeding, according to a recent Cochrane review.
Colon cancer, also known as colorectal cancer, is one of the most common types of cancer worldwide. Prevention typically includes maintaining a healthy lifestyle and undergoing regular screening tests. In recent years, the role of over-the-counter medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), in reducing the incidence of colon cancer has also been investigated.
NSAIDs (ibuprofen and aspirin) are commonly used to reduce inflammation, fever, and pain. However, their role in the primary prevention of colorectal cancer remains uncertain and controversial.
NSAIDs, including ibuprofen and aspirin, are commonly used to reduce inflammation, fever, and pain. However, their role in the primary prevention of colorectal cancer remains uncertain and controversial.
A research team from the West China Hospital of Sichuan University in China analyzed 10 randomized controlled trials, involving 124,837 participants, that evaluated whether aspirin or other NSAIDs could prevent colorectal cancer or precancerous polyps (adenomas) in people at average risk. The team found no suitable trials for NSAIDs other than aspirin, so their conclusions focus exclusively on this medication.
Little to No Benefit in the Short to Medium Term
The review found that aspirin likely does not reduce the risk of colon cancer in the first 5 to 15 years of apply. Some studies showed potential protective effects after more than 10-15 years of follow-up, but the certainty of this evidence is very low.
Potential protective effects were observed in some studies after more than 10-15 years of follow-up, but the certainty of this evidence is very low.
These potential long-term benefits came from observational phases of the trials, where participants may have stopped taking aspirin, started taking it independently, or begun other treatments, exposing the results to potential bias.
“While the idea that aspirin prevents colorectal cancer in the long term is intriguing, our analysis shows that this benefit is not guaranteed and comes with immediate risks,” explains Zhaolun Cai, the lead author of the review. This finding is particularly relevant as colorectal cancer remains a significant public health concern.
Immediate and Proven Risks
The results also show clear evidence that daily aspirin use increases the risk of serious bleeding outside the skull and likely increases the risk of hemorrhagic stroke.
While higher doses carry the greatest risk, low-dose aspirin also increases the risk of bleeding. Older adults and those with a history of ulcers or bleeding disorders may be particularly vulnerable.
Daily aspirin use increases the risk of serious bleeding outside the skull and likely increases the risk of hemorrhagic stroke.
the authors caution that any potential long-term benefits must be weighed against the immediate and known risk of bleeding.
“My biggest concern is that people may assume that taking an aspirin today will protect them from cancer tomorrow,” says Bo Zhang, the review’s principal author. “In reality, any potential preventative effect takes more than a decade to appear, if at all, while the risk of bleeding starts immediately.”
Not a One-Size-Fits-All Solution
Previous scientific evidence has shown potential benefits for people with a high genetic risk of colorectal cancer, such as those with Lynch syndrome. However, this review focuses strictly on people at average risk, and the long-term evidence for them proved to be very uncertain.
The authors urge patients not to start taking aspirin to prevent cancer without speaking with their healthcare provider about their personal risk of bleeding.
“This review reinforces that we need to move away from a one-size-fits-all approach,” says author Dan Cao. “The widespread use of aspirin in the general population is simply not supported by the evidence. The future is precise prevention, which uses molecular markers and individual risk profiles to identify who might benefit most and who is at greater risk.”
The widespread use of aspirin in the general population is simply not supported by the evidence.
The research team concludes that the story of aspirin for cancer prevention is much more complex than previously thought and that the balance of beneficial and harmful effects changes over time.
“As scientists, we must follow the evidence where it leads us,” adds Zhang. “Our rigorous analysis of the highest-quality trials reveals that the story of aspirin for cancer prevention is more complex than a simple yes or no. Current evidence does not support a general recommendation to take aspirin solely to prevent colon cancer.”
Reference:
“Aspirin and other non-steroidal anti-inflammatory drugs for preventing colorectal cancer and colorectal adenoma.” Cochrane, 2026.
Source: Cochrane
Rights: Creative Commons.
