Colorectal cancer (CRC) is amongst the most commonly encountered neoplasms worldwide, and both its prevalence and mortality have been increasing. Therefore, new strategies are needed to lower the burden of this disease. Recently, the effects of more than 200 agents (for example, non-steroidal anti-inflammatory drugs (NSAIDs), aspirin and selective cyclooxygenase-2 (COX-2) inhibitors) in preventing or protecting against CRC development have been evaluated. However, there are as yet no established methods to prevent CRC because of the lack of demonstrable efficacy and/or some adverse effects of the agents examined. On the other hand, removal of colorectal polyps has been shown to reduce the risk of future development of colorectal cancer and advanced adenoma, although there are still insufficient data on the recommended period of colonoscopic surveillance after polypectomy, especially in Japan. Moreover, the problems of missing and standardized colonoscopic observation methods have not been resolved yet. We hope to discuss possible methods to prevent CRC occurrence and diagnose CRC in the early stage. We sincerely look forward to the discussions being based on high-quality studies in this session!