 It has been found that the chemical changes that take place in a patients body during the development of inflammation may provide an environment which stimulates cancer cells. One step in the development of inflammation is the production of certain chemical substances which are important in the formation and spread of tumours. These are called prostaglandins. Cyclo-oxygenase II COX-2 is an enzyme a substance that speeds up chemical changes in the body involved in the production of these prostaglandins and although it is not usually present in most tissues it is made at the sites of inflammation. Celecoxib is a selective Non-Steroidal Anti Inflammatory Drug NSAID which works by blocking the action of the COX-2 enzyme, leading to a decrease in the production of prostaglandins and a reduction in inflammation. 