When colon cancer is suspected, one of a lower GI series (barium enema
x-ray) or colonoscopy is performed to confirm the diagnosis and localize the
tumor.
A barium enema involves taking x-rays of the colon and rectum after the patient is given an enema with a white, chalky liquid containing barium. The barium colon on x-rays. Tumors and other abnormalities appear as dark shadows on x-rays.
Colonoscopy is a procedure whereby a doctor inserts a long, flexible viewing tube into the rectum for the purpose of inspecting the inside of the entire colon. Colonoscopy is generally considered more accurate than barium enema x-rays, especially in detecting small polyps. If colon polyps are found, they are usually removed through the colonoscope and sent to a pathologist. The pathologist examines the polyps under a microscope to check for cancer. When the majority of polyps are removed through the colonoscopes are benign, many are not cancerous (precancerous). Removal of precancerous polyps prevents the development of colon cancer in the future of these polyps.
If the growth-cancerous growth found during colonoscopy, tissue samples are small (biopsies) can be obtained and examined under a microscope to confirm the diagnosis. If colon cancer is confirmed by a biopsy, examinations are conducted to determine whether the cancer has spread to other organs. Since colorectal cancer tends to spread to the lungs and liver, these tests usually include chest x-rays, ultrasonography, or a CAT scan of the lungs, liver, and stomach.
Sometimes, the doctor can get a blood test for CEA (carcinoembyonic antigen). CEA is a substance produced by some cancer cells. He sometimes found in high levels in patients with colorectal cancer, especially when the disease has spread.
