What if an aspirin a day could keep cancer away? A growing body of scientific research suggests that aspirin can prevent some cancers of the digestive system, and maybe even breast and prostate, too. In the latest study, published today in the journal Cancer Epidemiology, Biomarkers & Prevention, Yale University researchers found that patients from 30 hospitals across the state were less likely to develop pancreatic cancer if they took a small, daily dose of aspirin. Researchers are stopping short of recommending aspirin as a broad cancer prevention tool, because of its possible side effects, including stomach pain and gastrointestinal bleeding. “Aspirin is not a risk-free substance,” said Dr. Harvey Risch, a professor of Epidemiology at the Yale School of Public Health, who led the research.