[Prevention and early diagnosis of colorectal cancer]

Colorectal cancer (CRC) is one of the most common cancers in Norway. An increasing incidence is observed. CRC develops from benign adenomas in the colon over a long time. This paper reviews the evidence for drug prevention and screening for CRC.

Medline was systematically searched using the MeSH terms "Colorectal neoplasm AND prevention and control", with a limitation on randomised trials in humans.

Acetylsalicylic-acid, non-steroidal anti-inflammatory drugs and COX-2 inhibitors are shown to reduce adenoma growth, but it remains uncertain whether these drugs reduce the incidence of CRC. The drugs are associated with serious side-effects. Drug-prevention of CRC can therefore not be recommended. Faecal occult blood testing (FOBT) is the only CRC screening method where randomised trials have shown to effectively reduce CRC mortality. FOBT has no effect on CRC incidence and reduced compliance and effect have been observed over time. Endoscopic screening has a potentially larger effect, and can theoretically prevent CRC, but high quality studies are needed. Data from randomised trials are awaited for sigmoidoscopy screening. Colonoscopy screening has not been subjected to randomised trials and can thus not be recommended for population-based screening.