Colorectal, or bowel, cancer is the third most common cancer worldwide, making up 10% of cancer diagnoses.It most commonly affects people over the age of 50, but cases in younger people are increasing.Studies have found that in people with a genetic risk, such as Lynch syndrome, daily aspirin can cut their risk of colorectal cancer.
However, a new review has found that, for the general population, daily aspirin appears to offer no protection against colorectal cancer, and may have other adverse effects.
Colorectal, or bowel, cancer is the third most common cancer worldwide. According to the World Health Organization (WHO)Trusted Source, in 2022 alone there were 1.9 million new cases of colorectal cancer and it caused more than 900,000 deaths around the world.
Although most cases occur in people over the age of 50, in some countries incidence is rising in younger people. But the condition can be prevented by following a healthy lifestyle, and screening to detect early signs.
Some research has suggested that, in people with a genetic risk for colorectal cancer, a daily low dose of aspirin can reduce that risk.
Other studies have shown that it may help prevent recurrence in people who have had colorectal cancer.
But a new review of the evidence, carried out by researchers from West China Hospital of Sichuan University in China, and published in the Cochrane Database of Systematic Reviews, suggests that for people without genetic risk or prior colorectal cancer, there is no evidence that taking daily aspirin reduces colorectal cancer risk.
Conclusion based on 10 randomized control trials
The researchers included 10 trials in their analysis, with a total of almost 125,000 participants. All trials were comparing the effect of aspirin against placebo or no intervention on the risk of primary colorectal cancer or precancerous polyps (colorectal adenomaTrusted Source) in older adults.
Participants’ mean ages ranged from 53 to 71 years, and most were white. Seven of the studies used a low daily dose of 75-100 milligrams (mg) of aspirin, although three used higher doses of up to 500 mg per day.
All studies measured incidence of colorectal cancer within the follow up period that ranged from 5 to more than 15 years. Six studies also recorded deaths from colorectal cancer.
In addition, the studies recorded serious adverse events of aspirin treatment, including bleeding events such as extracranial hemorrhage (bleeding outside the skull but under the scalp) and hemorrhagic strokeTrusted Source (bleeding within the brain usually due to blood-vessel rupture.
