MIAMI • People who take aspirin regularly have a significantly lower risk of cancer, particularly involving the colon and gastrointestinal tract, according to US research.
The findings in the Journal of the American Medical Association Oncology suggest that aspirin use should complement - not replace - established preventive screening measures such as colonoscopies.
"We now can recommend that many individuals consider taking aspirin to reduce their risk of colorectal cancer - particularly those with other reasons for regular use, such as heart disease prevention," said senior author Andrew Chan of the Massachusetts General Hospital.
"Our findings imply that aspirin use would be expected to prevent a significant number of colorectal cancers above and beyond those that would be prevented by screening and may have even greater benefit in settings in which the resources to devote to cancer screening are lacking."
Previous research has shown that regular aspirin use can help prevent colorectal cancer. But the wider effect on all cancers is less clear.
Researchers looked at 32 years' worth of data from nearly 136,000 nurses and health professionals who answered health surveys.
Our findings imply that aspirin use would be expected to prevent a significant number of colorectal cancers above and beyond those that would be prevented by screening.
SENIOR AUTHOR ANDREW CHAN, of the Massachusetts General Hospital, on the study that looked at 32 years' worth of data.
Those who took a regular aspirin or a low-dose aspirin at least twice a week showed a 3 per cent lower risk of any type of cancer than those who did not report regular aspirin use.
The protective benefit of aspirin "appeared after five years of continuous use at dosages ranging from 0.5 to 1.5 standard tablets a week or one low-dose tablet a day", according to the study published yesterday.
Aspirin use reduced the risk of colorectal cancer by 19 per cent and the risk of any gastrointestinal cancer by 15 per cent.
Regular aspirin use "could prevent close to 30,000 gastrointestinal tract tumours in the US each year", said the study.
The team said aspirin use could "prevent an additional 7,500 colorectal tumours among US adults over 50 who have endoscopic screening and 9,800 among the almost 30 million who are not screened".
However, when the researchers looked specifically at common cancers such as breast, lung and prostate cancers, they found no risk reduction from aspirin use.
The research is based on observational studies, and is thus not as strong as that from a randomised controlled trial.
Aspirin also carries certain risks, such as bleeding and stroke, and cannot be tolerated by everyone.
The US Preventive Services Task Force recommends aspirin to prevent colorectal cancer and cardiovascular disease among many adults.
According to Mr Ernest Hawk of the University of Texas MD Anderson Cancer Centre, the study "is important because it suggests that aspirin use may complement colorectal cancer screening", he wrote in an accompanying editorial.
Aspirin also "may have an absolute benefit regardless" of whether patients have been screened by traditional methods, "a critical insight that few other studies have provided thus far", added Mr Hawk, who was not involved in the study.