Current concepts in colorectal cancer prevention with cyclooxygenase inhibitors.

Abstract

Colorectal cancer is one of the commonest malignancies worldwide. Recently, there has been much speculation regarding the role of cyclooxygenase-2 (COX-2) suppression in chemoprevention. Drugs with the ability to inhibit COX-2 expression include aspirin, nonsteroidal anti-inflammatory drugs (NSAID) and selective COX-2 inhibitors. Any strategy for chemoprevention must be able to quantify how effective the potential treatment is likely to be and which drugs will be most useful. We would also need to know for how long the agent could be taken safely and if any side-effects could preclude long-term use. Evidence from observational studies and recent updates of randomised controlled trials have been very encouraging - at least indicating benefit from the long term use of aspirin, even at low dose, with greatest impact on prevention of proximal colon cancers and adenomas. Most studies do, however, also warn that risks of gastrointestinal bleeding increase with long-term use of aspirin and related drugs. The risk-to-benefit ratio of a chemoprevention regimen using these medications needs to be carefully examined.