March 20, 2012 -- Millions of Americans who take an aspirin every day to lower their risk for heart attack and stroke may also be lowering their cancer risk.

New research adds to the growing evidence that daily aspirin may help prevent certain cancers from occurring.

On top of that, daily aspirin may also be an effective treatment for people who already have cancer.

In a series of studies published in The Lancet, researchers in the United Kingdom expanded on previous research linking daily low-dose or full-strength aspirin use to a reduced risk of death from cancer over a decade of follow-up.

In their latest work, the researchers examined the short-term impact of aspirin therapy on cancer, finding a reduction in cancers after about three years of daily aspirin use, says University of Oxford professor of medical neurology Peter M. Rothwell, MD, PhD, who led the studies.

People taking aspirin for as few as five years had a lower risk of dying from cancer and of having their disease spread once it had been diagnosed.