Diagnosis of Colorectal Cancer
by Michelle Badash, MS
Your doctor will first review your medical history. A complete medical exam will be done. Your doctor may recommend different tests in order identify tumors and confirm diagnosis.
Tests Used to Identify Potential Colorectal Cancers
Digital Rectal Exam —Your doctor will insert a lubricated gloved finger into the rectum. The doctor will check the rectum for lumps or abnormal areas. Rarely colon cancers can be detected in this way.
Fecal Occult Blood Test —A small sample of stool is placed on a special card. It is then tested by a lab for hidden blood. Blood can be present in the stool for many reasons. Colorectal cancer will not always cause blood in the stool. If positive, the test should be followed up with a more specific test such as endoscopy. A negative result does not guarantee that colorectal cancer is not present.
Endoscopy —In endoscopy, the doctor inserts a flexible tube into the bowel. The tube contains a camera that is used to examine the interior surface of the bowel. The doctor will look for irregularities, such as polyps. Two types of endoscopy include:
Polypectomy —The removal of a polyp or polyps during sigmoidoscopy or colonoscopy.
Barium Enema—A barium liquid is put into the rectum by way of the anus. Barium is a metallic compound that helps highlight the image of the lower gastrointestinal tract on an x-ray.
Virtual Colonscopy —A type of CT scan that uses computer software along with CT imaging to examine to colon for polyps. A rubber catheter is used to introduce air into the colon. This procedure is still being studied. Some of the benefits of a virtual colonoscopy include:
Tests to Confirm Diagnosis
Diagnosis of colorectal cancer is done by biopsy. A biopsy is a tissue sample that is removed from the colon or rectum. After removal, the sample is sent to a pathologist for examination.
Staging of Colorectal Cancer
Staging is a careful attempt to determine whether the cancer has spread from the inner lining of the colon. If the cancer has spread, staging will also help determine what body parts are affected.
If cancer is found, the prognosis and treatment depend on the location, size, and stage of the cancer and your general health.
Additional tests to determine the cancer’s stage may include:
If colorectal cancer is diagnosed, the following staging classification is used to identify how and where the cancer has spread.
Colon and rectal cancer. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/types/colon-and-rectal. Accessed May 14, 2013.
Colorectal cancer. American Cancer Society website. Available at: http://www.cancer..... Updated January 17, 2013. Accessed May 14, 2013.
Colorectal cancer. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed/what. Updated May 3, 2013. Accessed May 14, 2013.
Last reviewed September 2012 by Mohei Abouzied, MD
Last Updated: 09/11/2012