Achieving high Aspirinations

By Lauren Hoskin

Last year, new evidence was released to indicate that taking 75mg of aspirin daily could in fact reduce the risk of colorectal cancer and some other cancers by up to 40%. This evidence was the summary of 8 clinical trials, measuring the effects in 25,570 patients. The use of aspirin is shown to be associated with a 20% reduction in risk of death from colorectal cancer as a general figure, but increases to 30-40% reduction if aspirin is used for 5 years or more.

So how does a little pill which usually treats headaches reduce the risk of cancer?

Aspirin works as an anti-inflammatory agent, blocking the behaviour of a useful little enzyme called COX-2 which is present in all normal cells. COX-2’s job is to produce a hormone called prostaglandin, and to do so it must use its active site. This is where aspirin comes in; it blocks COX-2’s active site, rendering it useless and hence stopping the production of prostaglandin.

Prostaglandins have a wide and varied activity. They regulate muscle movements, conduct feelings of pain to the brain and also act as messenger molecules to cause inflammation. This explains the use of aspirin for reducing pain, swelling and tenderness. However, more specifically some prostaglandins can promote the growth of tumours by transmitting signals between cancerous cells to grow, divide and migrate. Consequently, one way to stop this process of tumour growth is to inhibit the enzyme that generates prostaglandin, COX-2, and hence inhibit the activity of prostaglandin itself. Additionally, aspirin has the ability to help stop blood clotting which can reduce the chances of heart attacks.

Sound too good to be true? Well, much controversy still surrounds the daily use of aspirin in regards to possible side effects. Because of its actions in the stomach and gut, it has been known to cause gastrointestinal bleeding (bleeding in the digestive system) and liver problems as well as cardiovascular problems. However, these are rare side effects and do not affect the majority of aspirin users. Many believe that we should use the knowledge we now have to develop a more specific COX-2 inhibitor, which could reduce the risk of cancer without increasing the risk of other diseases. Regular aspirin use is therefore a double edged sword, but one that may potentially be worth the risks…