Recent interest has focused on the role that
inflammation may play in the development of
prostate cancer and whether use of
aspirin or other nonsteroidal antiinflammatory drugs (
NSAIDs) affects risk. In a population-based case-control study designed to investigate the relation between these medications and
prostate cancer risk, detailed exposure data were analyzed from 1,001 cases diagnosed with
prostate cancer between January 1, 2002, and December 31, 2005, and 942 age-matched controls from King County, Washington. A significant 21% reduction in the risk of
prostate cancer was observed among current users of
aspirin compared with nonusers (95% confidence interval (CI): 0.65, 0.96). Long-term use of
aspirin (>5 years: odds ratio = 0.76, 95% CI: 0.61, 0.96) and daily use of low-dose
aspirin (odds ratio = 0.71, 95% CI: 0.56, 0.90) were also associated with decreased risk. There was no evidence that the association with
aspirin use varied by disease aggressiveness, but there was effect modification (P(interaction) = 0.02) with a genetic variant in
prostaglandin-endoperoxide synthase 2 (
PTGS2) (rs12042763).
Prostate cancer risk was not related to use of either nonaspirin
NSAIDs or
acetaminophen. These results contribute further evidence that
aspirin may have chemopreventive activity against
prostate cancer and highlight the need for additional research.