Colorectal cancer chemoprevention
The scientific and clinical rationale for prevention of colorectal
cancer (CRC) is firmly established [1]. CRC prevention
strategies include population screening, endoscopic
surveillance of high-risk groups, chemoprevention (the use
of drugs, vitamins or other food supplements), and health
education leading to lifestyle modifications such as weight
loss and physical activity [1].
The long natural history of human ‘sporadic’ colorectal
carcinogenesis, during which tumor initiation and benign
adenoma (or polyp) growth precede transformation into a
clinically apparent malignant adenocarcinoma (or cancer)
over a number of years, has been the basis for CRC
prevention strategies aimed at detection and removal of
asymptomatic colorectal adenomas in healthy individuals
(either directly by colonoscopy- or flexible sigmoidoscopy
(FS)-based screening [2], or indirectly via colonoscopy
prompted by faecal occult blood testing [1]). Colonoscopic
polypectomy has been demonstrated to reduce CRC mortality
[3]. However, risk reduction was approximately 50%
in the US National Polyp Study analysis [3] and ‘interval’
CRC during screening and surveillance programmes is increasingly
recognized [4]. Therefore, there is still an unmet
clinical need for safe and effective CRC chemoprevention,
in combination with existing screening and surveillance
programmes [5].