Regular aspirin use has been associated with a reduced risk for colorectal cancer. Now a review of studies has found that it may reduce the risk for several other digestive tract cancers as well.
Researchers pooled data from 113 studies and found that daily aspirin use among people aged 40 to 75 was associated with a 27 percent reduction in the risk for colorectal cancer, a 36 percent reduction in stomach cancer, a 33 percent reduction in esophageal cancer, a 38 percent reduction in liver and gallbladder cancer, and a 22 percent reduction in pancreatic cancer. For all these tumors, the favorable effect increased with duration of use.
The analysis, in The Annals of Oncology, found no effect of aspirin on the risk for cancers of the head and neck.
For colorectal cancer prevention, dosage may be significant. Low dose aspirin (75 to 100 milligrams a day) was associated with a 10 percent risk reduction, the regular 325 milligrams with a 35 percent reduction, and 500 milligrams a day with a 50 percent reduction in risk. For other cancers, the association with dosage is unclear.
The senior author, Dr. Carlo La Vecchia, a professor of epidemiology at the University of Milan, said that aspirin use must first be discussed with a doctor, because in some people it can cause bleeding that can be life-threatening. And for some cancers, he pointed out, such as stomach cancer, there remains a possibility of reverse causation — that is, aspirin may irritate the stomach and esophagus, leading some people at risk for those cancers to stop taking it. But, he said, “The evidence for the benefits of aspirin is solid, especially for liver and pancreatic cancer prevention.”
