Long-term Aspirin Use and Lower Pancreatic Cancer Risk

Fran Lowry

June 30, 2014

The longer a person takes low-dose aspirin, the lower the risk for pancreatic cancer, according to a study published online June 26 in Cancer Epidemiology, Biomarkers & Prevention.

This finding adds to increasing evidence of the preventive properties of aspirin in pancreatic and other cancers, said senior author Harvey A. Risch, MD, PhD, professor of epidemiology at Yale School of Public Health in New Haven, Connecticut.

He and his colleagues systematically assessed aspirin use in all 362 patients diagnosed with pancreatic cancer in Connecticut from 2005 to 2009 and in a random sample of 690 cancer-free control subjects from the general population.

All 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 used (low or regular dose), and when they stopped using aspirin.

Of the participants, 57% were men, 92% were non-Hispanic white, 49% were former or current smokers, and 19% had been diagnosed with diabetes in the 3 years preceding study enrollment.

Low-dose aspirin, usually taken to prevent cardiovascular disease, was defined as 75 to 325 mg per day. Regular-dose aspirin, usually taken for pain or anti-inflammatory purposes, was defined as doses higher than 325 mg taken every 4 to 6 hours.

For every year of aspirin use, the risk for pancreatic cancer decreased by 6% with low-dose aspirin (odds ratio [OR], 0.94; 95% confidence interval [CI], 0.91 - 0.98) and by 2% with regular-dose aspirin (OR, 0.98; 95% CI, 0.96 - 1.01).

The reduction in risk for pancreatic cancer was greater in people who started taking low-dose aspirin 20 years before study enrollment than in those who started 3 years before enrollment (60% vs 48%).

In addition, discontinuation of aspirin use in the 2 years prior to the study enrollment was associated with a 3-fold increased risk for pancreatic cancer, compared with continued use (OR, 3.24; 95% CI, 1.58 - 6.65).

"People who are developing pancreatic cancer have various physiologic changes, including taste disorders, that start to occur 2 to 3 years before their cancer is diagnosed," Dr. Risch explained. "They are more likely to quit using aspirin, so it may be difficult to separate the various aspects of patterns of aspirin use and risk of pancreatic cancer."

He cautioned that aspirin use is not without risks and that it is important for each individual to weigh the risks and benefits.

"People who are already taking aspirin because they are at increased risk for cardiovascular disease or they have a family history of colon cancer or other indication can feel confident that their usage is not going to increase their risk of pancreatic cancer, and it may decrease it," he said.

In addition, people at increased risk for pancreatic cancer, such as those with appreciable family histories of pancreatic cancer or other cancers that might indicate an increased risk could benefit from low-dose aspirin.

For this small subset of individuals, "aspirin use could be part of a regimen designed to reduce their risk," Dr. Risch said.

The study was funded by the National Cancer Institute. The authors The authors have disclosed no relevant financial relationships.

Cancer Epidemiol Biomarkers Prev. Published online June 26, 2014. Abstract


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