Aspirin use and pancreatic cancer mortality in a large United States cohort

Background: Results from some epidemiologic studies have suggested that aspirin use may reduce risk of pancreatic cancer, but the evidence remains limited. Methods: We examined the association between aspirin use and pancreatic cancer mortality among 987 590 U.S. adults in the Cancer Prevention Study II (CPS-II) cohort. CPS-II participants completed a self-administered questionnaire in 1982 and were followed for mortality through 2000. During follow-up, there were 4577 deaths from pancreatic cancer (2434 in men and 2143 in women). We calculated rate ratios (RR) adjusted for age, sex, race, body mass index, diabetes, and cigarette smoking status. Results: Aspirin use was not associated with pancreatic cancer mortality. The rate ratio associated with aspirin use 30 or more times per month, compared with no use, was 0.97 (95% confidence interval [CI] = 0.86 to 1.09). Even participants who reported both frequent aspirin use (greater than or equal to30 times per month) and use for 20 or more years were not at decreased risk compared with nonusers (RR = 0.96, 95% CI = 0.69 to 1.33). We found no association between aspirin use and pancreatic cancer mortality in subgroup analyses by follow-up time, cigarette smoking status, or sex. Conclusion: Results from this large prospective study do not support an important effect of aspirin use on pancreatic cancer mortality.