Stages of CRC

Stages of Colorectal Cancer¹¹

People who are diagnosed with colon cancer when it is localised to the bowel (Stage 1–2) have a better chance of long-term survival.^12,13

Stage 0: (carcinoma in situ): the cancer cells are all contained within the inner bowel lining, with very little risk of them spreading further.

Stage 1: the cancer has grown through the inner bowel lining into the muscle wall of the bowel, but no further, and is not in the lymph nodes.

Stage 2a: the cancer has grown through into the outer covering of the bowel wall but there are no cancer cells in the lymph nodes.

Stage 2b: the cancer has grown through the outer covering of the bowel wall and into tissues or organs next to the bowel, but has not spread to the lymph nodes.

Stage 3a: the cancer is still in the inner layer of the bowel wall or has grown into the muscle layer, and 1–3 nearby lymph nodes contain cancer cells.

Stage 3b: the cancer has grown into the outer lining of the bowel wall or into the surrounding tissues or organs and 1–3 nearby lymph nodes contain cancer cells.

Stage 3c: the cancer can be any size and has spread to 4 or more nearby lymph nodes but not to any other part of the body.

Stage 4: the cancer has spread to other parts of the body, such as the liver or lungs, through the lymphatic system or the bloodstream.

References:
11: TNM and number stages of bowel cancer | Cancer Research UK. http://www.cancerresearchuk.org/about-cancer/type/bowel-cancer/treatment… (accessed March 3, 2015).
12: Cancer of the Colon and Rectum – SEER Stat Fact Sheets. http://seer.cancer.gov/statfacts/html/colorect.html (accessed March 3, 2015).
13: Brenner H, Bouvier AM, Foschi R, et al. Progress in colorectal cancer survival in Europe from the late 1980s to the early 21st century: the EUROCARE study. Int J Cancer J Int Cancer 2012; 131: 1649–58.