Daily Aspirin Fails to Reduce Colorectal Cancer Risk, Study Finds

Daily Low-Dose Aspirin Does Not Prevent Colorectal Cancer, Major Review Concludes

A comprehensive analysis of existing research has found that daily low-dose aspirin does not significantly reduce the risk of colorectal cancer. The review, published in the Cochrane Database of Systematic Reviews on April 1, also highlights potential harms associated with long-term aspirin use, including increased bleeding risks in and around the brain.

The findings challenge the assumption that aspirin could serve as a preventive measure against colorectal cancer, particularly in the general population. Researchers emphasized that while some long-term benefits were observed, their confidence in these conclusions remains low.

Key Findings from the Review

• No short-term protection: Daily aspirin use does not appear to reduce colorectal cancer risk within the first 15 years of use.
• Uncertain long-term benefits: Some evidence suggests potential preventive benefits after 15 years, but researchers stated they are “not confident” in these findings.
• Increased bleeding risks: Daily aspirin may elevate the risk of bleeding outside the skull and in the brain, posing serious health concerns.
• Complex time-dependent effects: The review highlights that aspirin’s impact on colorectal cancer risk and mortality is inconsistent and time-dependent.

“It is not possible to draw definitive conclusions or outline specific implications for the routine use of aspirin for [colorectal cancer] primary prevention based on the current evidence.”

— Researchers, Cochrane Database of Systematic Reviews

The review analyzed data from 10 randomized controlled clinical trials, encompassing over 120,000 participants. Most studies were conducted in North America and Europe, with participants typically taking low-dose aspirin (75-100 mg per day). Three studies evaluated higher doses.

Expert Recommendations: Lifestyle Changes Over Aspirin

Dr. Ketan Thanki, a colorectal surgeon at the MemorialCare Todd Cancer Institute at Long Beach Medical Center in California, advised against relying on aspirin for colorectal cancer prevention. He emphasized the potential complications of long-term aspirin use.

“This study demonstrates limited (if any) protective benefit from aspirin on risk of developing colorectal cancer in the general population. With the known potential complications of long-term aspirin use, I would recommend that people don’t take daily aspirin solely with the intent of reducing your risk of developing colorectal cancer.”

— Dr. Ketan Thanki

Instead, experts recommend adopting lifestyle habits to lower colorectal cancer risk, including:

• Eating a plant-based diet rich in fruits, vegetables, and whole grains.
• Limiting alcohol consumption to reduce risk factors.
• Engaging in regular physical activity to maintain overall health.

What This Means for Aspirin Use

The review serves as a cautionary note for individuals considering daily aspirin regimens. While aspirin is widely used for its anti-inflammatory and blood-thinning properties, its role in colorectal cancer prevention remains unproven. The researchers stressed that the potential harms, particularly bleeding risks, outweigh the uncertain benefits for most people.

The study is an update to a previous review published in February, reinforcing the need for further research to clarify aspirin’s long-term effects on colorectal cancer risk.