Taking two aspirins a day reduced the risk of colorectal cancer by more than 60% in people with a family history of the disease, a large study shows.
“This is one more piece of evidence that there are some very positive effects of aspirin, and it should be considered very seriously for people who are at risk of colorectal cancer,” says Tim Bishop, one of the authors of the study and a professor of epidemiology at Leeds University in England.Observational studies have shown that aspirin lowers the risk of developing colorectal cancer, but this is the first randomized controlled trial to find the effect.
Researchers from the Universities of Newcastle and Leeds in England followed almost 1,000 patients from 43 medical centers in 16 countries. The patients all had Lynch syndrome, a genetic condition that predisposes people to develop colorectal cancer and other types of cancer.The patients were divided into two groups: One group took two aspirins every day (a total of 600 milligrams) for at least two years; the other group took a placebo.Among the findings, released Thursday online in The Lancet: Patients who took aspirin for at least two years had a 63% reduced risk of developing colorectal cancer. Women taking aspirin also had a reduced risk ofdeveloping endometrial or womb cancer, Bishop says. John Burn, lead author of the study and a professor at Newcastle University, says: “We have clear proof that aspirin prevents cancer in people at high genetic risk. We now have new questions to answer: Will low dose be as effective as two aspirins? Should all people at increased risk take aspirin?”
Bishop says researchers don’t know for sure how aspirin works to prevent cancer, “but one speculation is that the active part of aspirin causes DNA-damaged cells to die.””If I had a family history of bowel cancer, I would feel quite strongly about taking aspirin regularly,” he says. “There are certainly lots of benefits of taking aspirin,” Bishop says. “But people have to weigh the tradeoffs. With larger doses of aspirin comes the increase danger of ulcers and vascular bleeds.”Eric Jacobs, an epidemiologist with the American Cancer Society, said in statement that “there is good evidence that long-term regular aspirin use can also modestly reduce risk of colorectal cancer in people who do not have Lynch syndrome.”
“However, aspirin use is not currently recommended specifically for cancer prevention because even low-dose aspirin can increase risk of serious stomach bleeding.”Aspirin use should be discussed with a health care provider, he says.There are many ways to help prevent colorectal cancer, Jacobs adds. “All people 50 or older should get tested for colon cancer, so that precancerous polyps can be found and removed before they ever turn into cancer. In addition, maintaining a healthy weight, being physically active, not smoking and eating less red meat can help lower risk of colorectal cancer.”Funding for the study came from several medical groups in the United Kingdom, Bayer and other companies.