Dec. 7 (Bloomberg) -- Aspirin, a century-old medicine known to relieve pain and prevent blood clots, also reduces the risk of death from a variety of cancers, researchers said.
Taking 75 milligrams of aspirin a day for more than five years cut deaths from cancer by 20 percent, according to the study published in The Lancet medical journal today. The researchers found the pill was associated with a reduced risk of death from esophageal, colorectal, lung and prostate cancers.
The findings, based on data from eight trials involving 25,570 patients, expand on previous studies that found aspirin lowered the risk of colon cancer. More studies are needed before aspirin, which can increase the risk of internal bleeding, should be recommended for cancer prevention, said the researchers, led by Peter Rothwell, professor of clinical neurology at the John Radcliffe Hospital in Oxford, England.
“I have been taking aspirin for several years," Rothwell, who founded the Stroke Prevention Research Unit at the University of Oxford, told reporters in London yesterday. "I personally believe this."
The risk of death after 20 years was lowered in patients who took aspirin by 60 percent for esophageal cancer, 40 percent for colorectal cancer, 30 percent for lung cancer and about 10 percent for prostate cancer. Aspirin doses greater than 75 milligrams didn’t appear to increase the benefit. The data came from trials whose main purpose was to determine aspirin’s effect on cardiovascular risks such as heart attack and stroke.
Healthy middle-aged men and women may benefit the most from taking aspirin over a long period, and medical guidelines ‘‘may be updated on the back of these results,” Rothwell, 46, said.
“The benefit is likely to be less at 75 to 80 because those cancers that will kill you will have already developed,” he said.
Aspirin blocks prostaglandins, which are involved in a range of functions such as the contraction of blood vessels and inflammation. The eight trials reviewed by Rothwell and his colleagues looked at the effects of aspirin on cardiovascular disease.
Taking aspirin almost doubles the risk of internal bleeding to one in every 2,000 to 3,000 people, Peter Elwood, an epidemiologist at Cardiff University who has published 300 research papers over 50 years, told reporters in London. That doesn’t increase the number of deaths, and the chance of cancer or stroke outweighs the risk from bleeding, he said.
“The man on the street knows betting odds,” said Elwood, 80, who has been taking aspirin since 1974 and wasn’t involved in the study. People should “evaluate the risks for themselves.”
A low daily dose of aspirin taken over an average of six years reduced colon cancer risk by 24 percent and the likelihood of dying from the disease by 35 percent, according to a separate study authored by Rothwell published in October by The Lancet. A trial published in the medical journal Gut in September found that 75 milligrams of aspirin taken daily lowered the risk of colon cancer by 22 percent after just one year.
The effects of the drug over a longer period are unknown, and further data on the risks of taking aspirin for tumors that affect women, such as breast cancer, is needed, Rothwell said.
“The problem is you can’t do a 30-year trial,” he said. “It’s tough to do a trial and keep patients compliant for more than a few years.”
The authors of the study plan to publish further research into the link between aspirin and cancer prevention next year, they said in an e-mailed statement.
The researchers funded the study through their own budgets. Rothwell and his four co-authors disclosed to the journal that they had individually received payments from drugmakers including AstraZeneca Plc, Bayer AG, Boehringer Ingelheim GmbH, Sanofi-Aventis SA, Bristol-Myers Squibb Co. and Servier Laboratories Ltd. that were unrelated to the study. Bayer, based in Leverkusen, Germany, is the inventor of aspirin.
“This study remains a very important new development in our understanding of how to prevent cancer in general,” Alastair Watson, a professor of translational medicine at the University of East Anglia who wasn’t involved in the study, said in an e-mailed statement.
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