Three new studies report that taking an asprin a day may reduce the risk of cancer and prevent new tumors from spreading.
One of the new studies examined patient data from dozens of large, long-term randomized controlled trials involving tens of thousands of men and women. Researchers at the University of Oxford found that after three years of daily aspirin use, the risk of developing cancer was reduced by almost 25 percent when compared with a control group not taking aspirin. After five years, the risk of dying of cancer was reduced by 37 percent among those taking aspirin.
A second paper that analyzed five large randomized controlled studies in Britain found that over six and a half years on average, daily aspirin use reduced the risk of metastatic cancer by 36 percent and the risk of adenocarcinomas — common solid cancers including colon, lung and prostate cancer — by 46 percent.
Daily aspirin use also reduced the risk of progressing to metastatic disease, particularly in patients with colorectal cancer, the studies reported.
In the United States, two major studies of low-dose aspirin to prevent cancer did not find reductions in cancer with aspirin use. Those findings were excluded from analysis by the Oxford researchers because they involved use of aspirin every other day, rather than daily use.
Though many Americans use baby aspirin daily to reduce their risk of heart disease, patients are generally advised to do so only when their cardiac risk is presumed to outweigh the risks of taking aspirin. Physicians remain extremely reluctant to recommend long-term use of aspirin in a healthy population.
The third study which reviewed clinical case studies which is less rigorous but results are gleaned quickly, found a 38% reduced risk for developing colon cancer, and similar relative reductions for esophageal, stomach and breast cancer.
These analyses support, but are not proof, of aspirin’s role in helping to prevent cancer. Since none of the studies from which the data were drawn were designed to test the effect of aspirin on cancer, what we have is an association but not definitive information on cause and effect. It’s intriguing and certainly enough to have a conversation with your doctor to explore the risks versus the benefit of taking aspirin. And we will encourage and then follow the results of future studies that are specifically designed to test this relationship. Several studies are either underway or in the planning stages. We hope that aspirin being a low cost generic drug does not inhibit studies from going forward.