The role of nutrition and chemoprevention in colorectal cancer: from observations to expectations

During the last 20 years the role of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) in reducing the risk of colorectal cancer was shown in more than 100 animal studies. Support derives from 23 of 25 epidemiological studies confirming this protective effect. The COX-2 specific inhibitors and the selective apoptotic anti-neoplastic drugs offer the benefit of cancer protection without the gastrointestinal toxicity that was reported for the 'old' drugs. The presence of multiple molecular targets offers the potential for combination. The pivotal question in the puzzle of NSAID chemopreventive treatment should not be 'if' but 'how'. The concept that different food components may initiate or prevent cancer was illustrated by different epidemiological studies and animal models. Yet the chemical and biological complexity of the food, the difficulty in measuring habitual diets and the unavoidable changes in food constituents following a specific change in diet all contribute to this complexity.