Colon Cancer

What Is Colon Cancer Staging?

Staging is a method to describe how advanced a cancer is. Staging for colorectal cancer takes into account the depth of invasion into the colon wall, and spread to lymph nodes and other organs:

• Stage 0 (Carcinoma in Situ): Stage 0 cancer is also called carcinoma in situ. This is a precancerous condition, usually found in a polyp.
• Stage I: The cancer has spread through the innermost lining of the colon to the second and third layers of the colon wall. It has not spread outside the colon.
• Stage II: The cancer has spread outside the colon to nearby tissues.
• Stage III: Cancer has spread to nearby lymph nodes, but not to other parts of the body.
• Stage IV: Cancer has spread to other parts of the body, such as the liver or lungs.

Colon cancer is “staged” according to the pathological findings (results from biopsy) after surgery. Staging may include findings from imaging studies, such as chest x-ray, CT scan, a computer-assisted diagnostic procedure that produces cross sectional images of the body, MRI, PET scan, and endorectal ultrasound. Not all of these tests are needed in every person.

Staging helps the doctor to:

• Forecast how an individual may do over time
• Estimate the risk of recurrence
• Develop an individualized treatment plan for a patient

Depending on the stage of the cancer, the doctor can recommend surgery alone or in combination with radiation and chemotherapy. The approach to treatment is individualized to each person and the stage of their disease.

Endorectal Ultrasound

Endorectal ultrasound (ERUS) may be performed in a person with rectal cancer. In an ultrasound test, sound waves bounce off the part of the body to be examined and produce images of the area. These images are then displayed on a screen or monitor and saved for evaluation.

During an ERUS test, a probe is inserted into the rectum through the anus. The doctor then determines the depth of invasion of the cancer through the wall of the rectum and checks to see if the cancer has spread to lymph nodes or to organs adjacent to the rectum.

ERUS testing helps to stage the cancer prior to surgery. This way optimal therapy may be individualized for each patient. For example, if the ERUS determines that the cancer has penetrated completely through the rectal wall, the surgeon may request that treatment with radiation be given prior to surgery in order to shrink the tumor.