Does Aspirin Reduce Colorectal Cancer?

Previous findings have shown that regular use of aspirin or other non-steroidal anti-inflammatory drugs (NSAID) can reduce the risk of colorectal cancer. However, new findings published in JAMA show that some individuals with rare genetic variants do not share the same benefit.

"Previous studies, including randomised trials, demonstrated that NSAIDs, particularly aspirin, protect against the development of colorectal cancer, but it remains unclear whether an individual's genetic makeup might influence that benefit," co-senior author Andrew Chan of the Massachusetts General Hospital (MGH) Gastroenterology Division, said in a news release. "Since these drugs are known to have serious side effects - especially gastrointestinal bleeding - determining whether certain subsets of the population might not benefit is important for our ability to tailor recommendations for individual patients."

For the study, researchers analyzed data from 10 large population-based studies in North America, Germany and Australia. Then, they compared genetic and lifestyle data from 8,624 people who had developed colorectal cancer, along with 8,553 people who did not. Both groups were then matched by age, gender and other similar factors.

For most individuals, researchers found that regular NSAID use resulted in a 30 percent reduction of colorectal cancer risk. However, they found that regular use also resulted in no such protective effect among 9 percent of study participants who had genetic variations on chromosome 15. Those with even two rarer genotypes on chromosome 12 had a 4 percent increased risk of colorectal cancer.

However, researchers noted that future studies would be needed to determine what's right for certain individuals. 

"It is premature to recommend genetic screening to guide clinical care, since our findings need to be validated in other populations," Chan concluded.