In this study, daily use of adult-strength aspirin for 5 or more years
was associated with approximately 15% less overall cancer incidence,
as compared with no use, in both men and women, although
among women, this association was not statistically significant. The
lower overall cancer incidence associated with long-term daily aspirin
use was primarily the result of approximately 30% less colorectal
cancer incidence, approximately 20% lower prostate cancer
incidence, and approximately 15% lower incidence of female breast
cancer, although the reduction in female breast cancer was not statistically
significant.