Low-dose aspirin may reduce the risk of several types of digestive tract cancers, according to a team of researchers in Europe.
For the new study, the researchers analyzed 113 studies investigating colon/rectal ("bowel"), head and neck, esophageal, stomach, liver, gallbladder, bile duct and pancreatic cancers in the general population. The studies were published up to 2019.
The investigators concluded there was a link between regular use of aspirin -- taking at least one or two aspirin pills a week -- and a significant reduction in the risk of all these cancers, with the exception of head and neck cancer.
The study was published April 16 in the journal Annals of Oncology.
For colon/rectal cancer, extensive evidence stemmed from 45 studies. "There are about 175,000 deaths from bowel cancer predicted for 2020 in the European Union, of which about 100,000 will be in people aged between 50 and 74," said study senior author Dr. Carlo La Vecchia. He's a professor of epidemiology in the school of medicine at the University of Milan, Italy.
"If we assume that regular use of aspirin increases from 25% to 50% in this age group, this would mean that between 5,000 to 7,000 deaths from bowel cancer, and between 12,000 and 18,000 new cases could be avoided if further studies show that aspirin does indeed cause the reduction in cancer risk," La Vecchia said in a journal news release.
"Corresponding figures would be approximately 3,000 deaths each for esophageal, stomach and pancreatic cancer, and 2,000 deaths from cancer of the liver," La Vecchia added.
The study can't prove a direct cause-and-effect relationship. Still, aspirin use was associated with a 27% reduced risk of colon/rectal cancer, 33% reduced risk of esophageal cancer, 39% reduced risk of gastric cardia cancer (in the part of the stomach that connects to the esophagus), and a 36% reduced risk of stomach cancer, according to the study. It was also tied to a 38% lower risk of gallbladder and bile duct cancers, and 22% lower risk of pancreatic cancer.
La Vecchia added that taking aspirin to prevent any cancer "should only be done in consultation with a doctor, who can take account of the person's individual risk. This includes factors such as sex, age, a family history of a first-degree relative with the disease, and other risk factors. People who are at high risk of the disease are most likely to gain the greatest benefits from aspirin."
The U.S. National Cancer Institute has more on stomach cancer.