Using aspirin long-term reduces the risk of gastrointestinal tract malignancies, JAMA Oncology reports.
American researchers followed 88,084 women and 47,881 men for up to 32 years. Over this time, 20,414 cancers developed among women and 7,571 among men. Regular aspirin use was associated with a 3 per cent lower risk of developing cancer. A 15 per cent lower incidence of gastrointestinal tract cancers, including a 19 per cent reduction in colorectal cancers, accounted for most of aspirin’s benefit. Regular aspirin use did not influence the risk of breast, advanced prostate or lung cancer.
Aspirin’s benefits on gastrointestinal cancers emerged with at least 0.5 to 1.5 standard aspirin (325mg) tablets a week. However, people had to take aspirin for at least six years to benefit.
For example, people who took 0.5 to 1.5 standard aspirin tablets a week were 14 per cent less likely to develop colorectal cancer than nonusers. The risk fell to 16 per cent for two to five tablets a week, 24 per cent for six to 14 tablets and 39 per cent for at least 15 tablets a week.
The authors estimate that regular aspirin use could prevent 1.8 per cent of cancers overall, 8.0 per cent of gastrointestinal tract malignancies and 10.8 per cent of colorectal cancers. Among people older than 50 years of age, regular aspirin use could prevent 17.0 per cent of colorectal cancers (33 per 100,000 person-years respectively) among those who had not undergone a lower endoscopy.
Regular aspirin use could also prevent 8.5 per cent of colorectal cancers (18 per 100,000 person-years respectively) among people who had received lower endoscopy.