الفهرس 
Colorectal cancerOnly 14 pages are availabe for public view
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Abstract
Colorectal cancer (CRC) is a major worldwide health problem due to its high prevalence and mortality rate. Despite of there has been a recent increase in the understanding, diagnosis and treatment of CRC, the exact mechanisms contributing to the origin and development of CRC remain complex and unclear. Generally, CRC results from an accumulation of genetic and epigenetic changes in colon epithelial cells. CRC represents about 6% of cancers in Egypt.
CRC does not have any early signs, symptoms are often absent or uncharacteristic until a tumour has grown to a significant size to induce complications. Many patients have advanced disease when diagnosed. 90% of symptomatic cases are not diagnosed until the cancer has penetrated through the bowel wall or spread to local or distant regions. CRC screening, which detects both precancerous polyps and CRC, can reduce both CRC incidence and mortality.
Colonoscopy-guided biopsy is the gold standard for CRC diagnosis. Different screening methods can help to detect polyps or cancer in the colon and rectum including flexible sigmoidoscopy, colonoscopy and FOBT. However, sigmoidoscopy and colonoscopy are invasive procedures and may be difficult to be used as screening tools in asymptomatic individuals. While FOBT, although simple and non- invasive technique its use is limited by its relative poor sensitivity at detecting early-stage lesions, being only 50-60%.
Tumour markers such as CEA and CA19-9 have long been used to manage cancer, including diagnosis, determining prognosis, surveillance for recurrence and assessment of response to therapy. However, these markers have poor sensitivity and specif.