Diagnosis of Colorectal Cancer

Digestive Diseases

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A number of diagnostic tests can be done to determine if you have colorectal cancer, and if so, to determine the stage of disease. These will enable our gastrointestinal team to develop an individualized treatment plan.

Blood Test, Colonoscopy & Sigmoidoscopy to Diagnose Colorectal Cancer

Doctors will perform a fecal occult blood test to detect any blood in the stool. If blood is found, your physician will most likely perform a colonoscopy or sigmoidoscopy to examine the colon and determine the cause of bleeding.

Colonoscopy and Sigmoidoscopy: What to Expect

Both procedures use an endoscope, a flexible tube equipped with a light and camera that is inserted into the rectum and guided into the colon. A colonoscopy is more comprehensive. It can examine the rectum and entire colon, but requires greater preparation on the part of the patient and the use of sedation. Preparations may include a liquid diet several days prior to the procedure, a laxative the night before, and an enema the day of the procedure. Alternatively, a sigmoidoscopy requires less preparation, usually just an enema the day of the procedure, and can be done without sedation. But the procedure is also less comprehensive and can examine only the rectum and the bottom two feet of the colon.

Physicians may also couple a sigmoidoscopy with another procedure known as a double-contrast barium enema. With this, barium is infused into the rectum via an enema tube and an x-ray is taken of the area. The barium helps produce a clearer, more detailed x-ray of the area.

Other Tests to Diagnose Colorectal Cancer

A number of other imaging tests such as ultrasound exams and computed tomography (CT or CAT) scan may be used to visualize organs and see if cancer is present.