Aspirin and risks of non-colorectal second primary cancer in patients with prior colorectal cancer.

1564 Background: Aspirin has been identified as reducing cancer incidence, especially colorectal cancer (CRC), distant metastasis and mortality. Secondary cancer prevention has not been investigated. To examine the potential effects of aspirin on non-colorectal SPMs prevention among patients with previous CRC Methods: We enrolled 92,392 patients with newly diagnosed CRC between January 1, 1997 and December 31, 2011 from the Taiwan’s National Health Insurance database. Participants with more than 90 cumulative defined daily doses (cDDD) of aspirin exposure are defined as aspirin users (n = 7,488) compared with non-users (n = 84,904). Development of non-colorectal SPMs was obtained from the Taiwan’s National Health Insurance database. The Cox proportional hazards model, and the Fine and Gray's proportional hazards model were used to estimate the cause-specific hazard ratios (HRs) and subdistribution HRs, respectively. Data analysis was conducted in April, 2014. Results: During the 15-year study period, 3,88...