Abstract A93: Daily aspirin use and cancer mortality in a large United States cohort

Abstract

Abstract Background: A recent pooled analysis of several randomized trials of daily aspirin for prevention of vascular events reported a 34% reduction (95% confidence interval (CI): 0.50–0.87) in overall cancer mortality during follow-up after five years on aspirin. However, some uncertainty remains about the magnitude of the effect of daily aspirin use, particularly long-term use, on cancer mortality. Methods: We examined the association between daily aspirin use and overall cancer mortality among 100,140 men and women in the Cancer Prevention Study II Nutrition Cohort with no history of cancer. Hazard ratios (HRs) were calculated adjusting for smoking and other risk factors. Results: During follow-up between 1997 and 2008, 5,138 participants died from cancer. Compared to no use, daily aspirin use at baseline in 1997 was associated with slightly lower cancer mortality (HR = 0.93, 95% CI: 0.86–1.00), although this association was not formally statistically significant and did not vary by duration of daily use (HR = 0.93, 95% CI: 0.85–1.01 for < 5 years use, HR = 0.94, 95% CI: 0.85–1.03 for ≥ 5 years use). In time-dependent analyses including 3,373 cancer deaths and using updated information from periodic follow-up questionnaires, daily aspirin use was associated with lower cancer mortality, but results did not differ by duration (HR = 0.84, 95% CI: 0.76–0.94 for < 5 years, HR = 0.85, 95% CI: 0.76–0.96 for ≥ 5 years). Associations between daily aspirin use and cancer mortality appeared similar for low-dose and adult-strength aspirin. Conclusions: These results are consistent with an association between recent daily aspirin use and modestly lower cancer mortality, but suggest any reduction in cancer mortality may be smaller than that observed with long-term aspirin use in the pooled trial analysis. Citation Information: Cancer Prev Res 2011;4(10 Suppl):A93.