Daily Low-Dose Aspirin Use May Reduce Risk of Developing Pancreatic Cancer


Key Points

  • Men and women who took low-dose aspirin regularly had a 48% reduction in their risk of developing pancreatic cancer, with those who took low-dose aspirin for a longer period of time experiencing greater benefit.
  • Discontinuation of aspirin use within 2 years prior to the study was associated with a threefold increased risk of pancreatic cancer compared with continuing use.
  • Daily aspirin use is associated with potential risks of gastrointestinal bleeding.

Men and women who took low-dose aspirin regularly had a 48% reduction in their risk of developing pancreatic cancer, according to a new study. In addition, the longer a person started taking low-dose aspirin, the greater the benefit, ranging from 48% reduction in people who started 3 years before the study to 60% reduction in those who started taking aspirin 20 years before the study. The study by Streicher et al is published in Cancer Epidemiology, Biomarkers & Prevention.

Study Methods

A population sample of newly diagnosed people with pancreatic cancer was recruited from 30 general hospitals in Connecticut between 2005 and 2009. There were 362 pancreatic cases and 690 controls included in this analysis. The study participants were interviewed in person to determine when they started using aspirin, the number of years they used aspirin, the type of aspirin they took (low dose vs regular dose), and when they stopped using aspirin. Confounding factors, including age, gender, race/ethnicity, body mass index, smoking history, education level, and history of diabetes, were also considered.

Of the study participants, 57% were men, about 92% were non-Hispanic white, about 49% were former or current smokers, and 19% had been diagnosed with diabetes within 3 years prior to the study. A low-dose aspirin regimen was defined as between 75 mg to 325 mg of aspirin daily taken prophylactically for heart disease prevention, and a regular-dose aspirin regimen was a dose of 325 mg to 1,200 mg every 4 to 6 hours taken for pain or anti-inflammation purposes. Ninety-six percent of the low-dose aspirin users and 92% of the regular-dose aspirin users reported daily aspirin use.

Study Findings

The researchers found compared with individuals who had never used aspirin, subjects who regularly used aspirin had a lower risk of a pancreatic odds ratio (OR) of 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).

Conversely, discontinuation of aspirin use within 2 years of the study was associated with a threefold increased risk of pancreatic cancer compared with continued use.

The researchers also noted that although reduced risk of pancreatic cancer was seen for both low- and regular-dose aspirin users, taking regular-dose aspirin several times per day increases the risk for major gastrointestinal bleeding by 4- to 10-fold, whereas daily low-dose aspirin use only doubles the risk of major gastrointestinal bleeding.

“Aspirin use has potential risks of its own, and, thus, the risks and benefits for each person have to be evaluated based on personal characteristics and considerations,” said Harvey A. Risch, MD, PhD, a coauthor of the study and Professor of Epidemiology in the Department of Chronic Disease Epidemiology at the Yale School of Public Health in New Haven, Connecticut, in a statement. “For the small subset of individuals with strong family histories of pancreatic cancer who otherwise have been evaluated to be at substantially increased risk of pancreatic cancer, aspirin use could be part of a regimen designed to reduce their risk.”

Dr. Risch is the corresponding author for the Cancer Epidemiology, Biomarkers & Prevention article.

Funding for this study was provided by the National Cancer Institute. The researchers reported no potential conflicts of interest.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.