After a patient is diagnosed with colorectal cancer, doctors will attempt to stage the extent of the cancer. The stage indicates whether or not cancer has spread and if so how far. This helps a colorectal specialist determine how severe the cancer is, and what the best course of treatment will be. Staging is determined by the results of biopsies, physical exams, and imaging tests.
Colorectal cancer has five stages: Stage 0, Stage I, Stage II, Stage III, and Stage IV. Here we will look at each stage, and what that stage means.
Stage 0 is the earliest stage of colorectal cancer. This stage is also referred to as carcinoma in situ or intramucosal carcinoma. In this stage, the cancer has not grown beyond the inner layer (mucosa) of the colon or rectum.
In Stage I the cancer has grown into the submucosa (the layer beneath the mucous membrane of the colon rectum) and it may have even grown into surrounding muscular tissue. However, the cancer has not spread to nearby lymph nodes or distant sites.
There are three sub-stages of Stage II colorectal cancer: IIA, IIB, and IIC. In A, the cancer has grown into the outermost layers of the colon or rectum but has not gone through them. In B, the cancer has grown through the wall of the colon or rectum but has not spread to any other tissues. In C, the cancer has grown through the wall and is attached to or grown into other nearby tissues. However, in all of these sub-stages the cancer has not spread to nearby lymph nodes or to distant sites.
Stage III also has three sub-stages: IIIA, IIIB, IIIC. In A, the cancer has grown through the inner lining or muscular layers of the intestine and spread to 1 to 3 nearby lymph nodes or areas of fat near the lymph nodes. In B, the cancer has grown through the bowel wall or to surrounding organs and in to 1 to 3 nearby lymph nodes. In C, regardless of how deep the cancer has grown it has spread to 4 or more lymph nodes. However, in all of these sub-stages the cancer has not spread to distant sites.
Stage IV is the last and most severe stage of colorectal cancer. It is broken up into two sub-stages: IVA, and IVB. In Stage IVA, the cancer may or may not have grown through the wall of the rectum, and it may or may not have spread to nearby lymph nodes, but it has spread to one distant organ or one distant set of lymph nodes. In Stage IVB, the cancer may or may not have grown through the wall of the colon or rectum, and it may or may not have spread to nearby lymph nodes, but it has spread to two or more distant organs, sets of lymph nodes, or distant parts of the abdominal cavity.
Other Information on Colorectal Cancer
Staging is an important part of the cancer-treating process. It lets the physician know what kind of treatment will be best for your particular case. To learn more about colorectal surgery and staging visit the American Cancer Society’s website or speak to your physician.
Colon cancer is the third most common type of cancer, and it is responsible for nearly 50,000 deaths per year. However, 60% of colon cancer deaths could be prevented with regular screenings and early detection. For this reason, it is important to know your body and keep in contact with your physician.
It is not clear what exactly causes colorectal cancer, but according to Dr. Francisco Itriago MD, “some studies have shown that red meat cooked over an open flame can contribute to the development of polyps that can then possibly turn cancerous.” Because the causes are unknown and even linked to common habits, it is doubly important that you be on the lookout for symptoms, and always be honest and thorough with your physician.