Question

Rates of breast, lung, colorectal, and pancreatic cancer are notably lower in groups of individuals taking regular low doses of aspirin. Can you describe a reason for this beneficial role for aspirin? Would this effect be seen with maximal doses of aspirin and why?

Answer 1

Asprin is a NSAID (Non steroidal anti inflammatory agent).The beneficial role of Aspirin in prevention of certain cancers is attributed to:

1. Anti-inflamatory action:- Chronic inflammation is a known risk factor causing cancers like colorectal cancer. So it makes sense if an anti inflammatory medicine is given.

2.COX2 (cyclooxygenase)inhibitor action:- COX2 is a protein that initiates a pathway that converts Arachidonic acid to prostaglandins. Prostaglandins promote cell growth,increase blood vessel development, and reduces cell death.All these promote early tumour growth.

3.Anti platelet action:-Platelets can travel in the body to the site of inflammation and cause more inflammation by activating COX2 pathway ( that I mentioned in para).This results in more inflammation and hence rapid growth of tumour.

Asprin also blocks COX1 protein .This is a protein that activates platelets. So by stopping activation of platelets Asprin will play a protective role.

4. Blocking WNT pathway. This pathway promotes normal tissue development. So if this pathway is working at a place where it should not be, Aspirin may help in blocking this pathway by blocking formation of Arachidonic acid and the steps thereon.

At low doses 75mg Aspirin inhibits platelet action.

At higher doses ,say,1g , Aspirin has anti - inflammatory action.

So in any case if the dose is high it will still have protective effect for prevention of certain cancers like breast, colorectal, pancreatic and lung cancer.

But ,since the bleeding tendencies increase with increasing dose, and there are many side effects of this drug , it might be used in a as low dose as possible.