Aspirin linked to slight but significantly lower risk of all cancers
Key Takeaways
People who took aspirin regularly for at least 5 years had a 3% reduced incidence of all cancers, including a 15% lower incidence of gastrointestinal tract cancers, according to a study published online March 8, 2016 in JAMA Oncology.
“We now can recommend that many individuals consider taking aspirin to reduce their risk of colorectal cancer—particularly those with other reasons for regular use, such as heart disease prevention—but we are not at a point where we can make a general recommendation for overall cancer prevention,” said senior author of the study Andrew Chan, MD, MPH, Chief of the Clinical and Translational Epidemiology Unit in the Massachusetts General Hospital (MGH) Division of Gastroenterology, in Boston, MA.
Although aspirin may prevent colorectal cancers irrespective of screening, substantially more cases appeared to be prevented among people who didn't undergo screening, the researchers found.
“Our findings imply that aspirin use would be expected to prevent a significant number of colorectal cancers above and beyond those that would be prevented by screening, and may have even greater benefit in settings in which the resources to devote to cancer screening are lacking,” said Dr. Chan, who is also an Associate Professor of Medicine at Harvard Medical School.
A number of studies have shown that regular aspirin use appears to prevent colorectal cancer, but aspirin’s effects on overall cancer risk has not been clear. To find out, the researchers in the current study analyzed 32 years’ worth of data from almost 136,000 participants in the Nurses’ Health Study and the Health Professionals Follow-up Study.
Participants who reported regular aspirin use—defined as taking either a standard tablet at least twice a week or a daily low-dose aspirin—had a 3% absolute lower risk of any type of cancer than those who didn’t take aspirin regularly. Regular aspirin was associated with a 19% reduced risk of colorectal cancer and a 15% reduced risk of any gastrointestinal cancer. No reduction was seen in the risk of breast, prostate, or lung cancer.
Regular aspirin use could prevent close to 30,000 gastrointestinal tract tumors in the US each year and an additional 7,500 colorectal tumors among Americans over 50 who have endoscopic screening, as well as 9,800 among the almost 30 million who are not screened. The benefit related to other gastrointestinal tumors appeared after 6 years and at the same dosage level (ie, a daily low-dose tablet) used to prevent cardiovascular disease, the study reported.
The findings also suggest that the use of aspirin may complement, although not replace, colonoscopy and other methods of cancer prevention.
“At this point, it would be very reasonable for individuals to discuss with their physicians the advisability of taking aspirin to prevent gastrointestinal cancer, particularly if they have risk factors such as a family history,” Dr. Chan said. “But this should be done with the caveat that patients be well informed about the potential side effects of regular aspirin treatment and continue their regular screening tests. Furthermore, aspirin should not be viewed as a substitute for colonoscopy or other cancer screening tests.”