Aspirin Doesn’t Prevent Colorectal Cancer, Review Finds—Here’s What Works Instead
A new large-scale review suggests that taking daily low-dose aspirin may not significantly reduce the risk of colorectal cancer and could introduce serious health risks, particularly related to bleeding. The analysis, published in the Cochrane Database of Systematic Reviews, examined data from 10 randomized controlled trials involving more than 120,000 participants. Researchers compared aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) with either no treatment or alternative interventions for preventing colorectal cancer and related conditions. Their findings showed that daily aspirin use likely provides little to no reduction in colorectal cancer risk within the first 5 to 15 years. While there may be some protective benefit after 15 years of consistent use, researchers emphasized that the long-term evidence remains uncertain.
Additionally, the review raised concerns about safety. Daily aspirin use was associated with an increased risk of serious bleeding events, including bleeding in the brain and hemorrhagic stroke. These risks may outweigh any unclear or delayed cancer-prevention benefits. Researchers also found mixed results regarding mortality. Aspirin use may slightly increase colorectal cancer-related deaths in the short term (within 5 to 10 years), show no meaningful difference between 10 and 15 years, and potentially reduce deaths after 15 years. However, these conclusions were also described as uncertain. Given the inconsistent findings, experts urge caution. Dr. Ketan Thanki, a colorectal surgeon at MemorialCare Todd Cancer Institute, noted that aspirin should not be taken solely to prevent colorectal cancer in the general population. However, certain high-risk groups—such as individuals with Lynch syndrome or those with a history of adenomatous polyps—may still benefit and should consult their healthcare provider.
The new review adds to an ongoing debate about aspirin’s role in cancer prevention. Some earlier studies suggested potential benefits, particularly among younger individuals or those with risk factors like obesity or smoking. Others, including more recent research, have found no protective effect and even suggested increased risks in older adults. Due to this uncertainty, the U.S. Preventive Services Task Force withdrew its previous recommendation supporting aspirin use for colorectal cancer prevention in certain age groups. Experts now emphasize individualized decision-making based on a person’s overall health, cardiovascular risk, and bleeding risk.
While aspirin’s role remains unclear, there is strong consensus on effective ways to reduce colorectal cancer risk through lifestyle changes. A healthy diet plays a major role, particularly one rich in plant-based foods and fiber, while limiting red and processed meats. Reducing alcohol consumption, avoiding tobacco, maintaining a healthy weight, and engaging in regular physical activity are also key strategies.Screening is another critical component of prevention. Routine tests such as colonoscopies can detect precancerous polyps early, significantly reducing the risk of developing colorectal cancer. Noninvasive screening options are also available for those who cannot undergo a colonoscopy. Ultimately, experts agree that lifestyle habits and regular screening remain the most reliable tools for preventing colorectal cancer. Anyone considering daily aspirin use should discuss the potential risks and benefits with their doctor to determine what is appropriate for their individual health profile.
