Colon Cancer Types
Almost 95% of the colon cancers are adenocarcinoma cancer. These types of cancers start growing from cells which are the basic units of the mucus membrane. The role of mucus is to lubricate the interior of the colon and the rectum (the lower/end part of the large intestine). This is the most common type of the colon cancer.
This type of colon cancer is rare and usually starts from the specialized hormone generating cells in the large intestine in the form of a tumor. They are also known as gastrointestinal carcinoid tumors.
Gastrointestinal stromal tumors
These are the tumors that start developing in the interstitial cells of Cajal, which are the specialized cells, situated in the inner wall of the colon. These tumors, sometimes, can be non- cancerous also. The cancer causing tumor can be found in any part of the digestive system; however, they are not so common in the bowel.
This cancer is known as the cancer of the immune system cells which usually take place in the lymph nodes but they can also occur in the bowel or other organs.
The cancer starts from the blood cells and in muscles or the connective tissues of the colon or in the rectum wall. This is the rarest cancer of the colon.
Colon Cancer Stages
In stage 0, the cancer starts growing beyond the interior layer of the colon or rectum wall. It is also called the carcinoma in situ or the intramucosal carcinoma.
In the stage 1, the cancer starts spreading through muscular mucosa and reaches the submucosa of the colon wall. However, in this stage, the cancer stays in the colon wall only.
The stage 2 of the colon can be further categorized into three levels,
The cancer reaches the outermost layer of the colon wall, however, has not spread through the layer or touched the nearby lymph nodes or organs.
The cancer has spread through all of the layers of the colon wall, however, still hasn't grown into the nearby organs.
The cancer has covered all the layers of the colon wall and started spreading into the nearby organs and tissues, however, not reached the lymph nodes or any distant organs.
The stage 3 can be further categorized into three levels on the basis of how far the cancer has spread and the number of lymph nodes affected by it.
In the first part of stage III, the cancer crosses the submucosa and might have spread into the muscular layer. In stage IIIA, the cancer spreads through at least 1 to 3 lymph nodes, however, still hasn't reached to any distant organ.
The cancer spreads through the farthest layer of the colon, however, has not reached to the nearby organs or any distant organ. In this stage, cancer has covered at least three lymph nodes but not more than six lymph nodes nearby the primary site.
Here, either the cancer has spread through the colon wall or not, but has grown to the four or more lymph nodes.
This is the most advanced stage of the cancer which is further categorized into two levels.
The cancer spreads through all the layers of the colon wall and has grown into the distant organs, like, lungs or liver.
It might be possible that the cancer hasn't spread through the lymph nodes nearby the organ but has grown to distant organ.
The cancer has spread to more than one organ.