| Abstract: |
Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer and the second leading cause of cancer- related deaths in the United States.Each year, approximately 140,000 individuals are diagnosed with CRC and more than 50,000 will die from this malignancy (Jemal et al., 2005).There is indirect evidence that most cancers develop from adenomatous polyps and that on average it takes 10 years for a <1 cm polyp to transform into invasive CRC. Given the finding that adenomatous polyps are precursors to cancer and that polyps and early cancers are usually asymptomatic, there is a strong rationale to support screening asymptomatic individuals for early cancer detection and prevention (Stryker et al., 1987).In women, it ranks third after lung and breast cancer, and in men it ranks third after lung and prostate cancer. Incidence and mortality from colorectal cancer are similar in both men and women (Greenlee et al.,2001).In 2008, it is estimated that 148,810 men and women will be diagnosed with CRC and 49,960 will die from this disease (Jemal et al., 2008).Five-year survival is 90% if the disease is diagnosed while still localized (ie, confined to the wall of the bowel), but only 68% for regional disease (ie, disease with lymph node involvement), and only 10% if distant metastases are present (Ries et al., 2007).
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