Colon Cancer & Rectal Cancer Staging

If the biopsy shows that colorectal cancer is present, your doctor needs to know the extent (stage) of the disease to plan the best treatment, which could include a clinical trial. Several tests were run to diagnose colon or rectal cancer. They will be used in the staging process as well.

The stage is based on whether the tumor has invaded nearby tissues, whether the cancer has spread outside of where it started, and, if so, to what areas of the body.

The most commonly used staging system for colon and rectal cancers is the TNM system established by the American Joint Committee on Cancer (AJCC). TNM stands for:

• T: the size of the tumor and any spread of cancer into nearby tissues
• N: the spread of cancer to nearby lymph nodes
• M: metastasis, which refers to the spread of cancer to other parts of the body

The data collected for each of these will result in a cancer stage indicated by Roman numerals ranging from 0 to IV(4). Generally, the lower the number, the smaller the tumor and with less spread. Stage IV indicates that the cancer is advanced and has metastasized to other areas of the body.

Doctors classify colorectal cancer into the following stages:

Stage 0 Colorectal Cancer

The cancer is only found in the innermost lining of the colon or rectum. Stage 0 colorectal cancer is referred to as carcinoma in situ, or pre-cancer.

Stage I Colorectal Cancer

The tumor has invaded the inner wall of the colon or rectum but has not grown through the wall.

Stage II Colorectal Cancer

The tumor extends deeper into or through the wall of the colon or rectum and may have invaded nearby tissue. Cancer cells have not yet spread to the lymph nodes.

• Stage IIA: The cancer has penetrated the wall of the colon or rectum but has not spread to nearby tissues or lymph nodes.
• Stage IIB: The cancer has grown through the muscle layers to the lining of the abdomen (visceral peritoneum) but has not spread to the nearby lymph nodes or any other areas.
• Stage IIC: The tumor has spread through the wall of the colon or rectum and has invaded nearby structures. It has not spread to the nearby lymph nodes or other parts of the body.

Stage III Colorectal Cancer

The cancer has spread to nearby lymph nodes, also referred to as node-positive, but has not grown in distant parts of the body.

• Stage IIIA: The cancer has grown through the inner lining or into the muscle layers of the intestine and has spread to 1 to 3 lymph nodes or to a nodule of tumor cells in tissues around the colon or rectum that are not lymph nodes, but it has not spread to distant sites.
• Stage IIIB: The cancer has penetrated through the bowel wall or to surrounding organs and into 1 to 3 lymph nodes or to a nodule of tumor in tissues surrounding the colon or rectum that are not lymph nodes. It has not spread to other areas of the body.
• Stage IIIC: The cancer, regardless of how deep it has grown, has spread to 4 or more lymph nodes, but not to other distant parts of the body.

Stage IV Colorectal Cancer

The cancer has spread to other parts of the body, such as the liver or lungs.

• Stage IVA: The cancer has spread to a single distant part of the body, such as the liver or lungs.
• Stage IVB: The cancer has spread to multiple distant sites.
• Stage IVC: The cancer has spread to the peritoneum, the tissue lining your abdominal wall, and covers most of the organs in your abdomen. It may also have spread to other organs or sites.

Recurrent Colorectal Cancer

When cancer goes into remission, it can sometimes start growing again. The disease may recur in the colon, rectum, or another part of the body. It will be treated as colon or rectal cancer regardless of where it starts growing again.

If you were recently diagnosed with colon or rectal cancer and you’re in the Albany, New York area, our team of GI cancer doctors is here to guide you through the next steps, including treatment options.