Regular aspirin use may reduce overall cancer risk

Regular use of aspirin may reduce the overall risk of cancer, according to a new research which suggests that the drug may complement preventive benefits of colonoscopy and other methods of cancer screening.

The reduction primarily reflects a lower risk of colorectal cancer and other tumours of the gastrointestinal tract, researchers said.

"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 senior author Andrew Chan, from the Massachusetts General Hospital (MGH) in the US.

"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," said Chan.

A large number of studies have supported the ability of regular aspirin use to prevent colorectal cancer, but aspirin's effects on overall cancer risk has not been clear.

The researchers analysed 32 years of data from about 136,000 participants of two long term studies in the US.

They found that participants who reported regular aspirin use - taking either a standard or a low-dose aspirin tablet at least twice a week - had a 3 per cent absolute lower risk of any type of cancer than those not reporting regular aspirin use.

Regular aspirin use reduced the risk of colorectal cancer by 19 per cent and the risk of any gastrointestinal cancer by 15 per cent. No reduction was seen in the risk of breast, prostate or lung cancer.

Aspirin's protective benefit 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.

The benefit related to other gastrointestinal tumours appeared after six years and at the same dosage level - equivalent to a daily low-dose tablet - used to prevent cardiovascular disease.

"At this point, it would be very reasonable for individuals to discuss with their physicians the advisability of taking aspirin to prevent gastrointestinal cancer, particularly if they have risk factors such as a family history," said Chan, also an associate professor at Harvard Medical School in US.

"But this should be done with the caveat that patients be well informed about the potential side effects of regular aspirin treatment and continue their regular screening tests," Chan said.

The study was published in the journal JAMA Oncology.