People who have been taking low-dose aspirin for several years are at a lower risk of developing colon cancer, a new study suggests. This setup may also lower the overall risk of cancer by 3 percent, mostly due to reduced risk of colon cancer and other gastrointestinal (GI) tumors.

Researchers at the Massachusetts General Hospital analyzed two long-term studies with 32 years' worth of data from nearly 136,000 people who are part of the Nurses' Health Study and the Health Professionals Follow-up Study.

Participants who reported regular use of aspirin, which is defined as taking a low-dose of aspirin at least twice a week, had a 15 percent reduction in the risk of gastrointestinal tract cancers and a 19 percent decrease in the risk of colorectal cancer.

The study, which was published in the journal JAMA Oncology, shows that aspirin use may supplement, but not substitute, the preventive advantages of colonoscopy and other cancer screening methods.

Aspirin, however, was not linked with decreased risk for other cancers such as prostate, breast or lung cancer.

"Long-term aspirin use was associated with a modest but significantly reduced risk for overall cancer, especially gastrointestinal tract tumors. Regular aspirin use may prevent a substantial proportion of colorectal cancers and complement the benefits of screening," concluded the researchers.

Aspirin's Protective Benefit

In the study, the protective benefit of aspirin use appeared after about six years of constant intake. According to the study investigators, regular low-dose aspirin intake could prevent about 30,000 GI tumors in the U.S. every year.

It could also prevent up to 7,500 colorectal tumors among adults aged 50 years old and above who have diagnostic screenings such as endoscopic procedures and 9,800 others among the nearly 30 million people who are not screened.

"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 - but we are not at a point where we can make a general recommendation for overall cancer prevention," said Dr. Andrew Chan, from the Massachusetts General Hospital (MGH).

The study implies that aspirin use would prevent a significant number of colorectal cancers more than those prevented by screening options. It could also benefit those in settings where cancer screening resources are lacking.

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