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Screening and Diagnosis

An accurate diagnosis is the first step toward treating colorectal cancer. Physicians at the University of Chicago Medicine use many advanced tools and techniques to confirm or rule out the presence of a colorectal malignancy. We take a proactive approach to cancer screening – especially in high-risk patients – with the goal of catching the disease at an earlier, more treatable stage.

Diagnostic Tools

Your physician may use some of the following tests to screen for colorectal cancer:

  • Colonoscopy: A procedure in which a thin tube with a light and camera attached is inserted into the colon and rectum to look for polyps, abnormal areas or cancer.
  • Virtual colonoscopy: A noninvasive alternative to colonoscopy used to screen for colorectal cancers. Virtual colonoscopy (VC) uses X-rays and computers to produce three-dimensional images of the rectum, and then displays these images on a screen. Since sedation is not used for virtual colonoscopies, patients can go home after the procedure without the aid of another person and return to their usual activities right away.
  • Ultrasound: A test that uses sound waves to evaluate the depth of cancer, and involvement of lymph nodes. We offer both endoscopic ultrasound (EUS) and 3-D transrectal ultrasound (TRUS). During these procedures, a physician uses a special ultrasound probe to capture images or take samples of tissue.
  • Probe-based confocal laser endomicroscopy (pCLE): A precise technique for viewing tissue cells in the digestive tract at a cellular level. Using one of the world's smallest microscopes, physicians are able to detect and remove cancerous tissue during a single procedure. In more complex cases, doctors may send a patient immediately to surgery. The University of Chicago medical center is the only hospital in the region offering this advanced technique.


After a colorectal cancer diagnosis, it's important to determine the extent and size of the cancerous area. This process, which is known as staging, can help determine the best course of treatment. Some tools used for staging colorectal cancer include:

  • Computed tomography scan (CT scan): An imaging study that uses low energy X-rays to evaluate the extent of tumor involvement in the abdomen or pelvis. We have advanced 256-slice and 64-slice CT scanners that can rapidly produce detailed, three-dimensional images.
  • Magnetic resonance imaging (MRI): An imaging study that uses a strong magnet to generate a detailed picture of anatomy. This test is used for staging to evaluate the extent of tumor involvement in the abdomen or pelvis.
  • Positron emission tomography scan (PET scan): An imaging study that is sometimes used to stage the extent of disease. Radiolabelled glucose (sugar) is used to assess the location of any abnormally high level of metabolic activity.

Cancer Risk Assessment

The University of Chicago Medicine is home to a comprehensive cancer risk clinic. Our experts provide personalized risk assessment – including genetic testing and counseling -- for patients and families who are at increased risk of developing colorectal cancer. We work with individuals who have been diagnosed with certain gastrointestinal conditions, including inflammatory bowel disease and polyps, as well as families who have any cancer predisposition syndromes. » Learn more about our Gastrointestinal Cancer Risk and Prevention Clinic.