Daily aspirin use -- known to reduce the risk of colon cancer -- could also make the disease harder to treat if it does occur, researchers reported Wednesday, September 6, AFP reports.

The new findings based on mathematical modelling, if confirmed statistically and in the lab, would mean that aspirin's ability to ward off colon cancer may come at an unacceptably high cost, they cautioned.

Taking aspirin regularly "has been shown to reduce the incidence (of) a variety of cancers," including of the colon, noted the authors of a study in the Journal of the Royal Society Interface.

But at the same time, the drug may render the cancer "more difficult to manage therapeutically," they added.

"This indicates a potential trade-off."

A growing body of research has shown that daily micro-doses of aspirin taken for at least five years can slash the risk of cancer later in life.

Rates of prostate, throat and non-small-cell lung cancer all drop off significantly, with the incidence of colon cancer cut by up to half.

Other studies, meanwhile, have tested the impact of aspirin directly on cancer cells in the laboratory, showing that the common painkiller can slow the rate of cell division and boost cell death.

But scientists do not yet understand the mechanism at work, or know whether aspirin might have as-yet-undiscovered effects on cancer spread.

To find out more, researchers led by Dominik Wodarz of the University of California at Irvine -- who conducted these earlier experiments -- investigated whether the drug may cause dangerous cancer mutations.

Indeed, aspirin did boost the cancer's ability to produce aggressive, mutant cells that are drug-resistant, they found.

The results could challenge the protocol for aspirin use in cancer prevention.

It is now critical to ensure that aspirin delays "the onset of colourectal cancer by a sufficient amount of time to avoid the negative effects of this trade-off," the study authors said.