Researchers have determined once-a-day baby aspirin may decrease a person’s chance of developing colon cancer. With many aging Americans already taking aspirin daily to prevent heart attacks, the news signals hope for gastroenterologists and gerontologists.
The research was directed by John Baron, MD, of Dartmouth Medical School in Hanover, N.H. The team intended to determine if aspirin could prevent the return of polyps after a colonoscopy. Studying 1,121 otherwise healthy adults who previously had polyps removed, the team discovered aspirin decreased the chance of polyp recurrence by 19 percent. Study participants living in nine cities nationally were given either 80 mm of baby aspirin daily or a placebo.
A follow-up with the same group of participants three years later determined the group receiving aspirin had a 38-percent chance of polyp recurrence, in comparison to a 47-percent chance in the placebo group. A separate group receiving full-size aspirin had a 45-percent recurrence rate.
Baron said the years of research produced an unexpected response.
“It took several years to recruit the subjects and each subject was followed for three years,” he says. “So after six years of clinical work, we were able to get the preliminary data analyses done in a few months. We were surprised by the unusual dose-response relationship.”
Martin Avalos, MD, FACG at the VA Medical Center in Tampa, Fla., says he is not surprised by the findings and will consider recommending baby aspirin for patients he considers at risk of developing colon cancer.
“The protective effect of the aspirin did not become statistically significant until 20 years of steady aspirin intake,” he says. “With aspirin, we just need to tell people to be patient. It will take a long time to see the effects, but those who start taking it at age 40 will be OK.”
Avalos, who presented research concerning colon cancer screening at the 2001 Society of Gastroenterology Nurses and Associates (SGNA) conference, says for the majority of his patients, taking aspirin is already a habit.
“I work for the government, so most of the patients in the Veterans Administration (VA) system are already on aspirin for their hearts,” he says. “It is probably protecting their hearts, to begin with, but it is beneficial for their colons, too.”
An estimated 500,000 Americans take aspirin daily to prevent heart attacks. A January 2002 journal article in the Annals of Internal Medicine discussed new recommendations from the U.S. Preventive Services Task Force. The group urged Americans with statistical risks of having a heart attack to consult their physician about the benefits of taking aspirin. In the article, researchers state the more heart attack risk factors a person has, the more aspirin helps to prevent heart attacks.
Additional research concerning the effect of Vioxx and Celebrex on the recurrence of polyps is underway as well. The arthritis drugs are suspected to slow or prevent the growth of polyps but do not carry the side effects that can plague patients taking aspirin. Aspirin causes ulcers, bleeding and can prevent clotting.
Non-steroidal anti-inflammatory drugs, including aspirin, Celebrex and ibuprofen, reportedly block the production of prostaglandins, which are responsible for fueling colon polyp growth.
Colon cancer, which kills an estimated 48,000 Americans annually, can be determined in the early stages via a colonoscopy. As the second leading form of lethal cancer in the United States, colonoscopies are highly recommended. Patients age 50 and older should have the procedure every 10 years with a follow-up every three years if polyps are discovered.
Baron’s study, presented at the April meeting of the American Association for Cancer Research in San Francisco, was sponsored by the National Cancer Institute.