Chemoprevention of colon cancer: current status and future prospects.

Colorectal cancer is an important public health problem in the western world. Although some progress has been made in the prevention and management of this disease, colon cancer still remains one of the most common types of epithelial malignancies in both genders and is essentially incurable when it reaches the most advanced stages. Given the substantial morbidity and mortality associated with colorectal malignancies and their treatment, cancer prevention in its many forms emerges as a very attractive approach. Colorectal cancer chemoprevention refers to the administration of natural or synthetic compounds to block, reverse, delay or prevent the development of invasive large bowel neoplasms. The ultimate goal of implementing a chemopreventive intervention in the general, or alternatively, in an at-risk population is to decrease the incidence rate of the specific cancer being targeted. This article reviews the present status of colorectal cancer chemoprevention. Current insights into the molecular and genetic models of human colorectal carcinogenesis, preclinical models for efficacy testing as well as into promising biomarkers for colorectal chemoprevention are provided. The developmental status of many promising agents is also discussed emphasizing the epidemiological evidence, preclinical information substantiating an anticarcinogenic effect, their postulated mechanism of action and the status of human clinical development. Our perspective of the future prospects in this scientific area is also provided and has been predicated primarily on the firm belief that the proper integration of advances in the biology of colon carcinogenesis, experimental therapeutics and clinical trial methodology will be critical for the success of this promising field.