A new study looked at more than 1,200 Asian women and found that taking aspirin a few times a week was associated with a much lower risk of lung cancer – whether they smoked or not. The study concluded that aspirin reduced the risk by more than 50 percent, but could not prove that aspirin had a direct effect against lung cancer. But they support the association shown by other studies between routine aspirin use and reduced risk of specific cancers, including colon, prostate and esophageal cancers. The evidence suggests that aspirin can reduce cancer risk by as much as a quarter, but the drug needs to be taken for at least 10 years to see clinically meaningful benefits, which means that side effects have to be very low for it to work. Aspirin is known to have bleeding side effects. The drug causes an annual incidence of any upper gastrointestinal bleeding and severe gastrointestinal bleeding of 4% and 2%, respectively. In patients over 50 years of age, aspirin is particularly likely to increase the risk of spontaneous gastrointestinal bleeding. However, the addition of a proton pump inhibitor (e.g., omeprazole) significantly reduces this additional risk. The available evidence suggests that aspirin should ideally not be applied before the age of 55, even if one has secondary risk factors for heart disease or cancer. In addition, the initiation of aspirin application after the age of 75 years is not justified by the current human life expectancy and the need for long-term use of the drug to obtain benefits. Therefore, the net benefit is available only to those within the narrow age range of 55 to 75 years.