Tsoi KKF, et al. - Whether aspirin use prevented different cancers among Chinese users, was investigated. The long-term use of low-dose aspirin was found to be related to the reduction in risk of various cancers, but not for breast cancer.

Methods

• This was a population-based study.
• Researchers utilized database from the Hong Kong Hospital Authority.
• Participants were adults with aspirin prescription for at least six months between 2000 and 2004, followed up until 2013. 
• At a 1:2 ratio, they age-sex matched aspirin users to non-aspirin users.
• They assessed incidences of cancer (primary outcome) measured by relative risk (RR).

Results

• With the mean age 67.5 years, 204,170 aspirin users and 408,339 non-aspirin users were analyzed, with 7.7 years average duration of aspirin prescription, and 80mg as the median dose of aspirin.
• In 26,929 (13.2%) aspirin users and 70,755 (17.3%) non-users, cancer incidences were reported.
• A significant reduction of cancers in liver (RR:0.49); stomach (RR:0.42); colorectum (RR:0.71); lung (RR:0.65); pancreas (RR:0.54); oesophagus (RR:0.59); and leukaemia (RR:0.67) was seen with aspirin usage vs patients who had not been prescribed aspirin.
• Aspirin use did not result in any demonstrable reduction of kidney cancer, bladder cancer, prostate cancer and multiple myeloma.  
• Aspirin usage led to a marginal increase in (RR:1.14) breast cancer risk.