A recent study indicates that regular aspirin intake can significantly reduce the risk of colorectal cancer, particularly in individuals with high lifestyle-related risk factors. The research, led by Mass General Brigham, tracked men and women for over 30 years and found that those with less healthy lifestyles benefited the most from regular aspirin use.
Regular aspirin intake may lower the risk of colorectal cancer in individuals with significant lifestyle-related risk factors. This study, published in JAMA Oncology on August 1, 2024, suggests a more personalized approach to preventive aspirin use. “We sought to identify individuals who are more likely to benefit from aspirin to facilitate more personalized prevention strategies,” said Dr. Andrew Chan, co-senior author and Director of Epidemiology for the Mass General Cancer Center.
Colorectal cancer is the second-leading cause of cancer death in the United States, according to the National Cancer Institute. The U.S. Preventive Services Task Force had previously recommended daily low-dose aspirin for adults aged 50 to 59 to prevent cardiovascular events and colorectal cancer but withdrew the recommendation in 2016 due to concerns about gastrointestinal bleeding risks.
Researchers analyzed health data from 107,655 participants in the Nurses’ Health Study and the Health Professionals Follow-Up Study. They compared colorectal cancer rates between those who regularly took aspirin and those who did not. Regular aspirin use was defined as either two or more standard-dose (325 mg) tablets per week or daily low-dose (81 mg) aspirin.
The participants, followed from an average age of 49.4 years, showed significant differences in colorectal cancer incidence. Those who regularly took aspirin had a 10-year cumulative incidence of 1.98%, compared to 2.95% among non-aspirin users.
The greatest benefit was observed in individuals with the least healthy lifestyles. Those with the lowest healthy lifestyle scores had a 3.4% chance of developing colorectal cancer without aspirin, compared to 2.12% with regular aspirin use. In contrast, those with the highest healthy lifestyle scores had colorectal cancer rates of 1.5% in the aspirin group and 1.6% in the non-aspirin group. This implies that treating 78 individuals with aspirin would prevent one colorectal cancer case over 10 years in the least healthy group, compared to treating 909 individuals in the healthiest group.
“Our results show that aspirin can proportionally lower the markedly elevated risk in those with multiple risk factors for colorectal cancer,” said Dr. Daniel Sikavi, lead author and gastroenterologist at MGH. The study suggests healthcare providers might more strongly recommend aspirin to patients with less healthy lifestyles.
While the study included those taking regular standard-dose aspirin (325 mg) twice a week, Dr. Sikavi noted that “based on prior studies, the best evidence supports daily low-dose (81 mg) aspirin for prevention.”
Previous studies suggest aspirin reduces the production of pro-inflammatory proteins called prostaglandins, which promote cancer development. Aspirin may also inhibit signaling pathways that cause uncontrolled cell growth, enhance the immune response against cancer cells, and prevent the development of blood vessels supplying nutrients to cancer cells. “Aspirin likely prevents colorectal cancer through multiple mechanisms,” said Dr. Chan.
The study did not assess potential side effects of daily aspirin use, such as bleeding. Despite efforts to control for various risk factors, the observational nature of the study means there may be additional influencing factors.