Diagnosis Cancer

Colon Cancer

Your doctor will begin the evaluation by recording your medical history, asking about symptoms you may be experiencing and conducting a thorough physical examination. He or she may recommend one or more of the following diagnostic tests:

  • Barium Enema Also known as a lower gastrointestinal series, this test involves taking X-rays of the large intestines.
  • Biopsy In this test, a small amount of tissue from the suspected area is removed for examination by a pathologist to make a diagnosis.
  • Colonoscopy Colonoscopy is performed to see inside the rectum and the entire colon and remove polyps or other abnormal tissue for examination under a microscope. In addition to the standard colonoscopy, UCSF Medical Center offers a virtual colonoscopy.
  • Digital Rectal Exam This involves the doctor or nurse inserting a gloved, lubricated finger into the rectum to feel for any abnormalities.
  • Fecal Occult Blood Test This is a test for blood in the stool. Such blood may arise from anywhere along the digestive tract. Hidden blood in the stool is often the first, and in many cases the only, warning sign that a person has colorectal disease, including colon cancer.
  • Polypectomy This is performed during a sigmoidoscopy or colonoscopy to remove polyps.
  • Sigmoidoscopy Sigmoidoscopy is performed to see inside the rectum and the lower colon and remove polyps or other abnormal tissue for examination under a microscope.


If you're diagnosed with colon cancer, your doctor will identify the "stage" or extent of your disease. Staging is a careful attempt to find out if the cancer has spread and if so, to what parts of the body. This information helps your doctor develop the best and most effective treatment plan for your condition. More tests may be performed to help determine the stage.

The stages of colon cancer include:

  • Stage 0 The cancer is very early. It is found only in the innermost lining of the colon.
  • Stage I The cancer involves more of the inner wall of the colon.
  • Stage II The cancer has spread outside the colon to nearby tissue, but not to the lymph nodes. Lymph nodes are small, bean-shaped structures that are part of the body's immune system.
  • Stage III The cancer has spread to nearby lymph nodes, but not to other parts of the body.
  • Stage IV The cancer has spread to other parts of the body. If it spreads, colon cancer tends to spread to the liver and lungs.
  • Recurrent Recurrent cancer means the cancer has come back after treatment. The disease may recur in the colon or in another part of the body.

UCSF Health medical specialists have reviewed this information. It is for educational purposes only and is not intended to replace the advice of your doctor or other health care provider. We encourage you to discuss any questions or concerns you may have with your provider.