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Taking small doses of aspirin daily may lower the risk of developing pancreatic cancer, a new study suggests.
However, the risk of experiencing aspirin's side effects — for example, bleeding in the stomach — may outweigh the benefits for people who are not at high risk for pancreatic cancer, the researchers said.
The researchers looked at 362 patients with pancreatic cancer at 30 hospitals in Connecticut, as well as 690 healthy people, between 2005 and 2009, and asked them about their aspirin use and whether they took low-dose aspirin or the regular-dose type.
"We found that the use of low-dose aspirin was associated with cutting the risk of pancreatic cancer in half, with some evidence that the longer low-dose aspirin was used, the lower the risk," said study researcher Dr. Harvey Risch, a professor of epidemiology at the Yale School of Public Health in New Haven, Connecticut. [5 Interesting Facts About Aspirin]
Pancreatic cancer is a relatively rare cancer, but it's notoriously deadly. About one in 60 adults will get pancreatic cancer during their lifetime, and less than 7 percent of patients survive five years after the diagnosis, according to the National Cancer Institute.
Aspirin and cancer
Aspirin has been studied intensely for its potential role in reducing the risk of several cancers and diseases. Studies have suggested that taking this inexpensive and common drug can reduce the risk for heart disease.
But the findings don't mean that everyone should be taking daily aspirin to prevent pancreatic cancer, the researchers said, because aspirin increases the risk of internal bleeding and life-threatening complications.
Rather, the new results may simply reassure people already taking daily low-dose aspirin for other reasons, the researchers said. "There seems to be enough evidence that people who are considering aspirin use to reduce the risk for cardiovascular disease can feel positive that their use might also lower their risk for pancreatic cancer, and quite certainly wouldn't raise it," Risch said in a statement.
In the study, participants who took low-dose aspirin regularly for six years or less had a 39 percent lower risk of developing pancreatic cancer compared with people who didn't take aspirin. Taking low-dose aspirin for more than 10 years was linked with a 60 percent reduction in pancreatic cancer risk, according to the study, published today (June 26) in the journal Cancer Epidemiology, Biomarkers & Prevention.
The results held when the researchers took into account other factors known to affect people's risk of pancreatic cancer, such as body mass index, smoking habits and diabetes.
How aspirin may prevent cancer
Previous research on cancer-prevention effects of aspirin has yielded mixed results. But that may be because people in those studies had taken regular or high-dose types of aspirin, for pain relief from conditions that could be related to the risk for pancreatic cancer, Risch said. However, in more recent years, people have started using low-dose aspirin to prevent heart disease.
In the study, a dose of 75 to 325 milligrams of aspirin per day was considered low-dose aspirin, which is the dose usually taken for heart-disease prevention. A dose higher than that was considered regular-dose aspirin, taken for pain or anti-inflammation purposes.
It's not clear how aspirin may prevent cancer but several ideas have been suggested. For example, it is possible that the drug works by reducing inflammation, or by preventing cancer cells from reaching other organs through the bloodstream.
"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," Risch said. "For the small subset of individuals with strong family histories of pancreatic cancer, or 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."