Role Of CT And MRI In Staging Of Colorectal Carcinoma

More than 95% of colorectal cancers are adenocarcinoma that arises from non malignant but dysplastic adenomas that progress to invasive carcinoma during a period of 10-15 years. Colonoscopic removal of adenomas has been proved to reduce the incidence of colorectal carcinoma by at least 76%. (Yee et al. 2001)Risk factors include polyposis syndromes, inflammatory bowel diseases, dietary imbalance between fat, protein and fibers, smoking and alcohol intake.Since expected to take long time before majority of population change their dietary habits, early accurate diagnosis would be feasible way to reduce colorectal cancer mortality.Early diagnosis depends on presenting symptoms and screening followed by diagnostic studies. Screening is the process of research for cancer in people who have no symptoms of disease. Tests used in colon cancer can be divided into two large groups. 1) Stool blood tests (tests that mainly detect cancer), which test the stool for signs that cancer may present (tests for occult blood or exfoliated DNA). Such examinations are less invasive and easier to perform, but are less likely to detect polyps1. 2) Structural examinations (tests that can find early cancer and polyps). Such tests look at the structure of the colon and include flexible sigmoidoscopy (FSIG), colonoscopy, double-contrast barium enema