Diagnosis

If you have screening test results that suggest cancer or you have symptoms, your doctor must find out whether they are due to cancer or some other cause. Your doctor asks about your personal and family medical history and gives you a physical exam. You may have one or more of the tests described in the "Screening" section.

If your physical exam and test results do not suggest cancer, your doctor may decide that no further tests are needed and no treatment is necessary. However, your doctor may recommend a schedule for checkups.

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

You may want to ask your doctor these questions before having a biopsy:

• How will the biopsy be done?
• Will I have to go to the hospital for the biopsy?
• How long will it take? Will I be awake? Will it hurt?
• Are there any risks? What are the chances of infection or bleeding after the biopsy?
• How long will it take me to recover? When can I resume a normal diet?
• How soon will I know the results?
• If I do have cancer, who will talk to me about the next steps? When?

The prognosis of colorectal cancer is related to the depth of tumor, penetration into the bowel wall, and whether the cancer has spread to lymph nodes or other organs. These variables are represented in various staging systems (e.g. Dukes, TNM and Numerical) which are nearly equivalent: