Staging of colorectal cancer

Staging is the process of finding out how far the cancer has spread. This is very important because your treatment and the outlook for your recovery depend on the stage of your cancer. For early cancer, surgery may be all that is needed. For more advanced cancer, other treatments like chemotherapy or radiation therapy may be used.

There is more than one system for staging colorectal cancer. Some use numbers and others use letters. But all systems describe the spread of the cancer through the layers of the wall of the colon or rectum. They also take into account whether the cancer has spread to nearby organs or to organs farther away.

Stages are often labeled using Roman numerals I through IV (1-4). As a rule, the lower the number, the less the cancer has spread. A higher number, such as stage IV (4), means a more advanced cancer.

There are really 2 types of staging for colorectal cancer.

• The clinical stage is your doctor's best estimate of the extent of your disease, based on the results of the physical exam, biopsy, and any imaging tests you have had.
• If you have surgery, your doctor can also figure out the pathologic stage, which is based on the same factors as the clinical stage, plus what is found as a result of the surgery.

In some cases, the clinical and pathologic stages may be different. During surgery the doctor may find cancer in a place that did not show up on imaging tests. This might give the cancer a more advanced pathologic stage.

Because most patients with colorectal cancer have surgery, the pathologic stage is most often used to describe the extent of this cancer. Pathologic staging is likely to be more accurate than clinical staging.

Grade of colorectal cancer

Another factor that can affect the outlook for survival is the grade of the cancer. Grade is a description of how closely the cancer looks like normal colorectal tissue under a microscope.

Low-grade means the tissue looks more normal; high-grade means the tissue looks less normal. Most of the time, the outlook is not as good for high-grade cancers as it is for low-grade cancers. Doctors sometimes use the grade to help decide whether a patient should get more treatment with chemotherapy after surgery.