Experts still aren't sure, but it appears that aspirin blocks or reduces the action of the COX-2 enzyme. This is actually the same mechanism that makes aspirin ease pain and inflammation.
In a previous study by the same research team published in the New England Journal of Medicine, the researchers discovered that taking aspirin did not inhibit all colorectal tumors -- only those that over-express the COX-2 enzyme.
In this study, participants whose tumors tested positive for COX-2 lowered their risk of death by 61 percent and their overall mortality rate by almost 40 percent, so clearly aspirin was of great benefit for them. Those whose tumors were COX-2-negative didn't gain much, if any, benefit from taking aspirin.
This means that aspirin therapy's a gamble; you take it and maybe it will help you, or maybe you'll be one of those who won't benefit. The good news: Between 65 and 80 percent of colorectal tumors are COX-2 positive, so most colon cancer patients fall in this category. And since there aren't a lot of negative side effects from taking aspirin if you're monitored carefully, aspirin therapy is going to be worthwhile for most.
I have come to believe that Asprin is far too toxic to take long term, even in tiny amounts... I have seen it in the elderly and my father in particular who I believe was killed by it.. It builds up in the kidneys, and the elderly are susceptible to kidney problems without adding a further burden..Just my opinion based on the evience of my own eyes....