The longest part of the large intestine is the colon, and these tissues are where colon cancer arises. Colon cancer and rectal cancer are often grouped together, and either one can be referred to as colorectal cancer, according to the National Cancer Institute.
Stages
Cancer is staged to describe the extent and spread of the cancer, and the staging helps guide treatment and prognosis. Colon cancer is staged from Stage Zero, which is noninvasive, to Stage IV, which is metastatic, meaning it has spread to other organs.
Stage Zero
This stage is also called carcinoma in situ. The abnormal or precancerous cells are in the inner lining of the colon and have the potential to turn into cancer and invade other tissue, according to the American Cancer Society.
Stage I
Stage I colon cancer is cancer that has spread past the inner tissue of the colon wall, and has spread to the middle layers. Another name for Stage I colon cancer is Dukes A colon cancer.
Stage II
Stage II colon cancer consists of IIA and IIB. In Stage IIA, the cancer has spread past the middle layers of the colon wall, or is in the tissues that are surrounding the colon or rectum, according to the National Cancer Institute. Stage IIB includes cancer that has spread through the colon wall into surrounding organs or the peritoneum, which is the abdominal lining (cancer.gov).
Stage III
Stage III is split up into three substages: IIIA, IIIB and IIIC. These diagnoses encompass: cancer that has spread to the middle layers of the colon wall and at least three lymph nodes; cancer that is in at least three lymph nodes and is in surrounding tissues of the colon and rectum, or the peritoneum; and cancer that has spread to at least four lymph nodes and is in surrounding tissues, the peritoneum, or to nearby organs.
Stage IV
Stage IV colon cancer is also known as metastatic colon cancer, or Dukes D colon cancer. In this stage, the cancer has spread to distant organs and nearby lymph nodes. This is the most advanced stage.
