If the studies were done 20 years ago my guess is that the original trials were performed to see if aspirin reduced the risk of heart attacks.

Yes. The study's full text said: "We therefore determined the effect of aspirin on risk of fatal cancer by analysis of individual patient data for deaths due to cancer during randomised trials of daily aspirin versus control (done originally for primary or secondary prevention of vascular events) in which the median duration of scheduled trial treatment was at least 4 years."

There should be effective cures and preventative measures long before they are at significant risk.

Hope is not a plan.