Abstract
Background
Aspirin-use reduces colorectal cancer (CRC) incidence, but there is limited evidence regarding associations of aspirin and non-aspirin nonsteroidal anti-inflammatory drugs (NSAIDs) with CRC-specific survival.
Methods
This prospective analysis includes women and men from the Cancer Prevention Study-II Nutrition Cohort who were cancer-free at baseline (1992 or 1993) and diagnosed with CRC during incidence follow-up through 2015. Detailed information on aspirin and non-aspirin NSAID-use was self-reported on questionnaires at baseline, in 1997, and every 2 years thereafter. Pre- and post-diagnosis data were available for 2,686 and 1,931 participants without distant-metastases, respectively, among whom 512 and 251 died from CRC during mortality follow-up through 2016. Secondary analyses examined associations between pre-diagnosis aspirin-use and stage at diagnosis (distant-metastatic versus localized or regional). All statistical tests were two-sided.
Results
Long-term regular use of aspirin (>15 times per month) before diagnosis was associated with lower CRC-specific mortality (multivariable-adjusted hazard ratio (HR)= 0.69; 95% CI = 0.52–0.92). Post-diagnosis regular aspirin use was not statistically significantly associated with risk of CRC-specific mortality overall (HR = 0.82; 95% CI = 0.62–1.09), although participants who began regular aspirin use only after their diagnosis were at lower risk than participants who did not use aspirin at both the pre-and post-diagnosis periods (HR = 0.60; 95% CI = 0.36–0.98). Long-term aspirin use before diagnosis was also associated with lower odds of diagnosis with distant metastases (multivariable-adjusted odds ratio = 0.73; 95% CI = 0.53–0.99).
Conclusions
Our results suggest that long-term aspirin use before a diagnosis of non-metastatic colorectal cancer may be associated with lower CRC-specific mortality after diagnosis, consistent with possible inhibition of micro-metastases before diagnosis.
Long-term Use of Aspirin and Nonsteroidal Anti-inflammatory Drugs and Risk of Colorectal Cancer
