Colon cancer;
Stage 0 (also called carcinoma in situ) - the cancer is confined to the outermost portion of the colon wall.
Stage I - the cancer has spread to the second and third layer of the colon wall, but not to the outer colon wall or beyond. This is also called Dukes' A colon cancer.
Stage II - the cancer has spread through the colon wall, but has not invaded any lymph nodes (these are small structures that help in fighting infection and disease). This is also called Dukes' B colon cancer.
Stage III - the cancer has spread through the colon wall and into lymph nodes, but has not spread to other areas of the body. This is also called Dukes' C colon cancer.
Stage IV - the cancer has spread to other areas of the body (i.e. liver and lungs). This is also called Dukes' D colon cancer.
Rectum cancer:
Stage 0: the tumor is confined to the first layer of the rectal tissue. It is also called carcinoma in situ
Stage I: the tumor has spread through the innermost lining of the rectum into the second and third layers of the inside wall of the rectum, but has not spread outside the rectum
Stage II: the tumor has spread through the rectal wall into surrounding tissue, but has not spread to the lymph nodes
Stage III: the tumor has spread to the surrounding lymph nodes, but has not spread to other areas of the body
Stage IV: the tumor has spread to other areas of the body, such as the liver and lungs
