Chemoprevention of Colorectal Cancer

It is a disturbing reality that one of the most preventable cancers is also one of the most common and deadly. Worldwide, approx 950,000 people are diagnosed with colorectal cancer (CRC) each year, and deaths from CRC number almost 500,000 per year (1). The prevalence of this disease is disproportionately highest in more-developed countries, which account for 20% of the world's population but 64% of CRC cases and 60% of deaths due to the disease (2). Because CRC produces few, if any, symptoms until the disease is advanced, 35% of newly diagnosed cases already exhibit regional lymph node metastases, and 20% of new cases are stage IV, representing incurable disease (3). Data from migratory populations suggest that adaptation to a lifestyle characteristic of developed Western nations is associated with increased CRC incidence. For example, colon cancer incidence in Japanese men and women who have been lifetime residents of the United States now exceeds that of the US white population (3). In addition, the incidence of CRC in Japan has increased over the past 25 yr in concert with Westernization and is presently equivalent to that of Western Europe (3). These observations support a strong environmental role in CRC development and suggest that the problem is likely to increase as Western cultural and dietary influences expand.