Aspirin, a widely used weapon against heart attacks, might also play a role in cancer prevention, according to three new British studies.
"We have now found that after taking aspirin for three or four years there starts to be a reduction in the number of people with the spread of cancers, so it seems as well as preventing the long-term development of cancers, there is good evidence now that it is preventing the spread of cancers," says lead researcher Dr. Peter M. Rothwell, a professor of neurology at the University of Oxford and John Radcliffe Hospital in Oxford.
"Because aspirin prevents the spread of cancers, it could potentially be used as a treatment," he added.
Other studies have shown that a daily dose of aspirin taken over 10 years appeared to prevent some cancers, but the short-term benefits and the benefits for women weren't clear.
More recently, a daily low-dose aspirin has been recommended for people who have had a heart attack or stroke to prevent another.
"It may well be that taking aspirin to prevent cancer becomes the main reason for taking it," Rothwell said.
The theory, according to Rothwell, is that aspirin may work against cancer by inhibiting platelets, which promote clotting and also help cancer cells spread.
In one study, Rothwell's team analyzed data from 51 previous clinical trials comparing aspirin with no aspirin in preventing heart attacks.
The results indicated that overall, daily low-dose aspirin also reduced the risk of dying from cancer by 15 percent. Further, taking aspirin five years or more reduced the risk by 37 percent, and over three years, the risk reduction was about 25 percent for both men and women, the researchers discovered.
In addition, aspirin was associated with a 12 percent reduction in deaths from non-cardiovascular causes, they reported.
In another study, Rothwell's team examined the effect of aspirin on slowing the spread of cancer, or metastasis.
Their data derived from five clinical trials that also looked at daily low-dose aspirin (75 milligrams or more) and heart attack and stroke prevention. The researchers honed in on patients who developed cancer.
After more than six years of follow-up, low-dose aspirin reduced the risk of distant metastasis by 36 percent, compared with cancer patients receiving a placebo, they found.
Additionally, aspirin reduced the risk of metastasis in solid tumors, such as colon, lung and prostate cancer, by 46 percent and by 18 percent for cancers of the bladder and kidney.