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Diagnosing and Staging Colorectal Cancer

Because the signs and symptoms of colorectal cancer are not apparent until the disease has developed into a more advanced stage, it’s important to understand your family history and talk with your primary care physician about scheduling regular colorectal cancer screening. This is especially true if you are at a high risk of developing colorectal cancer.

Affiliated Oncologists recommends following the guidelines set in place by the American Society of Clinical Oncology, which is to begin colorectal cancer screening at age 45.

Screening Detects Colon & Rectal Cancers at Earlier Stages

Fortunately, several screening tests for colon and rectal cancers exist, including some recently made widely available. In addition to detecting colorectal cancer when it is present, regular screening can also prevent it by allowing your doctor to find and remove polyps before they have a chance to turn into cancer. If you’re 50 or older or have colorectal cancer in your family, we recommend talking to your doctor about colorectal cancer screening.

There are several common types of screening options. Colorectal cancer screening tests can include those performed at a healthcare clinic or those taken at home. It's important to keep in mind that at-home testing offers more privacy, but can often lead to a false positive or a misinterpretation of the results.

At-Home Testing for Colorectal Cancer

For people under the age of 50, doctors may suggest at-home testing before a colonoscopy. These methods allow you to test comfortably at home without a day of colon preparation before a colonoscopy. It's important to be aware that these tests can miss polyps and some cancers. Blood in the stool can result from an irritated polyp or cancerous tumor that does not cause enough bleeding to be seen during a bowel movement. A problem with FOBTs is that it is difficult to tell if the blood found is from within the colon or rectum. If there is blood detected, a colonoscopy is often the next step to see if the blood source is from within the colon.

  • Fecal Immunochemical Test (FIT)

    This test looks for hidden blood in the stool by reacting to the human hemoglobin protein part, which is found in red blood cells.

  • Guaiac-based fecal occult blood test (gFOBT)

    This is testing method is like the FIT, but with a different type of chemical reaction used to detect blood in the stool.

  • Stool DNA test

    A test that detects tiny amounts of blood in the stool (with an immunochemical test similar to FIT) as well as nine DNA biomarkers in three genes that have been found in colorectal cancer and precancerous advanced adenomas. This test can be conducted at home.


Colorectal Cancer Screening Performed at a Healthcare Facility

These screening tests for colorectal cancer are the most accurate and can allow the doctor to remove polyps found that may be suspicious. Your doctor will work with you to determine which of the following tests is the best one for you. Common colorectal cancer screening tests include:

  • Standard (or optical) colonoscopy

    In this test, the rectum and entire colon are examined using a colonoscope, a flexible, lighted tube with a lens for viewing, and a tool for removing tissue. The patient is sedated during a colonoscopy procedure.

  • Virtual (CT) colonoscopy

    This screening method, also called computed tomographic (CT) colonography, uses special x-ray equipment (a CT scanner) to produce a series of pictures of the colon and the rectum from outside the body.

  • Sigmoidoscopy

    In this test, the rectum and lower (sigmoid) colon are examined using a sigmoidoscope, a flexible, lighted tube with a lens for viewing, and a tool for removing tissue. The doctor cannot check the upper part of the colon, the ascending and transverse colon, with this test.

  • Double-contrast barium enema (DCBE)

    An enema can be given containing barium. Once the barium has moved into the colon, x-rays are taken. The images are used to detect areas where there may be cancer. It’s not a good option for identifying precancerous polyps but is better than nothing if a colonoscopy or other physical exam isn’t possible.

Although, it is recommended for men and women to begin screening for colorectal cancer at the age of 50, this can differ based on whether a patient is at average risk or high risk for the disease. Consulting with your doctor can help when it comes to making a decision on a screening test.


When Should You Start Colon & Rectal Cancer Screening?

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When Should You Start Colon & Rectal Cancer Screening?

What to Do If Test Results Come Back Abnormal

If the screening results suggest cancer or that you have symptoms of colorectal cancer, your doctor must find out whether they are due to cancer or some other cause. Additional testings may be needed before a doctor can diagnose colon or rectal cancer.

Tests showing an abnormal area (such as a polyp) may require a biopsy to check for cancer cells. Often, the abnormal tissue can be removed during colonoscopy or sigmoidoscopy. A pathologist checks the tissue for cancer cells using a microscope.

Remember that not all polyps are cancerous, but if pathology testing of the polyps removed during a colonoscopy shows that cancer is present, your doctor needs to know the extent (stage) of the cancer to plan the best treatment. The stage is based on whether the tumor has invaded nearby tissues, whether the cancer has spread and, if so, to what parts of the body.

The following tests may be used to diagnose and stage colorectal cancer :

  • Blood tests

    Your doctor checks for carcinoembryonic antigen (CEA) and other substances in the blood. Some people who have colorectal cancer or other conditions have a high CEA level.

  • Colonoscopy

    If colonoscopy was not performed for diagnosis, your doctor checks for abnormal areas along the entire length of the colon and rectum with a colonoscope.

  • Endorectal ultrasound

    An ultrasound probe is inserted into your rectum. The probe sends out sound waves that people cannot hear. The waves bounce off your rectum and nearby tissues, and a computer uses the echoes to create a picture. The picture may show how deep a rectal tumor has grown or whether the cancer has spread to lymph nodes or other nearby tissues.

  • PET-CT scan

    A PET scan uses small amounts of radioactive materials, a special camera, and a computer to create pictures of organs and tissues inside the body. When a PET scan is combined with a CT scan, it is usually called a PET-CT scan.

  • MRI

    The use of magnetic fields, not x-rays, to produce detailed images of the body. You may receive an injection of dye, called a contrast medium, to create a clearer picture. MRI is the best imaging test to find where the colorectal cancer has grown and spread.

  • CT scan

    An X-ray machine linked to a computer takes a series of detailed pictures of areas inside your body. You may receive an injection of dye. A CT scan may show whether cancer has spread to the liver, lungs, or other organs.

  • Chest X-ray

    X-rays of your chest may show whether cancer has spread to your lungs.


Stages of Colon and Rectal Cancer

  • Stage 0: The cancer is found only in the innermost lining of the colon or rectum. Carcinoma in situ is another name for Stage 0 colorectal cancer.
colorectal cancer stage 0
  • Stage I: The tumor has grown into the inner wall of the colon or rectum. The tumor has not grown through the wall.
colorectal cancer stage 1
  • Stage IIA: The cancer has grown through the wall of the colon or rectum but has not spread to nearby tissue or to the nearby lymph nodes.
  • Stage IIB: The cancer has grown through the layers of the muscle to the lining of the abdomen, called the visceral peritoneum. It has not spread to the nearby lymph nodes or elsewhere.
  • Stage IIC: The tumor has spread through the wall of the colon or rectum and has grown into nearby structures. It has not spread to the nearby lymph nodes or elsewhere.
colorectal cancer stage 2a 2b 2c
  • Stage IIIA: The cancer has grown through the inner lining or into the muscle layers of the intestine. It has spread to 1 to 3 lymph nodes or to a nodule of tumor cells in tissues around the colon or rectum that do not appear to be lymph nodes but has not spread to other parts of the body.
colorectal cancer stage 3a
  • Stage IIIB: The cancer has grown through the bowel wall or to surrounding organs and into 1 to 3 lymph nodes or to a nodule of tumor in tissues around the colon or rectum that do not appear to be lymph nodes. It has not spread to other parts of the body.
colorectal cancer stage 3b
  • Stage IIIC: The cancer of the colon, regardless of how deep it has grown, has spread to 4 or more lymph nodes but not to other distant parts of the body.
colorectal cancer stage 3c
  • Stage IV: The cancer has spread to other parts of the body, such as the liver or lungs.
colorectal cancer stage 4
  • Recurrence: This is cancer that has been treated and has returned after a period of time when the cancer could not be detected. The disease may return in the colon or rectum, or in another part of the body.

Colorectal Cancer Care in the South Chicago Suburbs

If you receive a colorectal cancer diagnosis, our cancer specialists at Affiliated Oncologists, here to help. We work with you to create a personalized colorectal cancer treatment plan designed specifically for you. Our cancer centers are located in Chicago Ridge, Mokena, Hazel Crest, Palos Heights, and Oak Lawn.