Aspirin and Cancer Prevention
The effect of aspirin on prevention is a long-term effect and that not very much happens in the 5 years after you start taking aspirin. The preventive effects are really quite long-term. The dose that was tested was 600 mg/day. It looks like all of the gastrointestinal cancers might be quite substantially affected. There also was emerging evidence for a few other cancers, notably breast cancer, ovarian cancer, lung cancer, and prostate cancer. Overall the deaths from cancer in these studies were reduced by 20%. The mechanisms could be as simple as the fact that aspirin reduces inflammation, and inflammation is associated with more rapid cell turnover. The more times a cell divides, the greater the chance for an error that could lead to a mutation leading to cancer. The other major issue is at what age to start and stop taking aspirin, and that is very much a balance between the benefits in terms of cancer and heart disease and the risks in terms of gastrointestinal bleeding. There is emerging evidence that bleeding effects are only serious in individuals over the age of 70 years.