Evidence suggests that regular aspirin use lowers the incidence of colorectal cancer (CRC) — a primary preventive effect. However, whether aspirin use affects cancer-specific outcomes after CRC is diagnosed (i.e., secondary prevention) is less clear. Among 23,162 patients who received CRC diagnoses between 2004 and 2011, 26% took aspirin (75–160 mg daily) regularly after their CRC diagnoses — presumably for cardiovascular, not cancer, prevention.
During median follow-up of 3 years, overall and CRC-specific mortality was 34% and 19%, respectively, in the aspirin-exposed group, and 42% and 32%, respectively, in the aspirin-unexposed group. In multivariable analyses adjusted for demographic factors, CRC stage and characteristics, and use of other drugs that might lower CRC risk (including nonsteroidal anti-inflammatory drugs), aspirin use was associated with significantly lower…
