The process used to find out if cancer has spread within the colon/rectum or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment.
Basic Overview
Stage 0: This is the earliest stage possible. Cancer hasn't moved from where it started; it's still restricted to the innermost lining of the colon. Also called Carcinoma in Situ.
Stage I: Cancer has begun to spread, but is still in the inner lining. Also called Dukes A colorectal cancer.
Stage II: Cancer has spread to other organs near the colon or rectum. It has not reached lymph nodes. Also called Dukes B colorectal cancer.
Stage III: Cancer has spread to lymph nodes, but has not been carried to distant parts of the body. Also called Dukes C colorectal cancer.