Background: Pancreas-cancer prognosis is dismal, with 5-year survival less than 5%. Significant relationships between aspirin use and decreased pancreas-cancer incidence and mortality have been shown in four of 13 studies.

Methods: To evaluate further a possible association between aspirin use and risk of pancreatic cancer, we used data from a population-based Connecticut study conducted from January 2005 to August 2009, of 362 pancreas-cancer cases frequency matched to 690 randomly sampled controls.

Results: Overall, regular use of aspirin was associated with reduced risk of pancreatic cancer [odds ratio (OR), 0.52; 95% confidence interval (CI), 0.39–0.69]. Increments of decreasing risk of pancreatic cancer were observed for each year of low-dose or regular-dose aspirin use (OR, 0.94; 95% CI, 0.91–0.98 and OR, 0.98; 95% CI, 0.96–1.01, respectively) and for increasing years in the past that low-dose or regular-dose aspirin use had started (OR, 0.95; 95% CI, 0.92–0.99 and OR, 0.98; 95% CI, 0.96–1.00, respectively). Reduced risk of pancreatic cancer was seen in most categories of calendar time period of aspirin use, for both low-dose aspirin and regular-dose aspirin use. Relative to continuing use at the time of interview, termination of aspirin use within 2 years of interview was associated with increased risk of pancreatic cancer (OR, 3.24; 95% CI, 1.58–6.65).

Conclusions: Our results provide some support that a daily aspirin regimen may reduce risk of developing pancreatic cancer.

Impact: Long-term aspirin use has benefits for both cardiovascular disease and cancer, but appreciable bleeding complications that necessitate risk–benefit analysis for individual applications. Cancer Epidemiol Biomarkers Prev; 23(7); 1254–63. ©2014 AACR.