The largest and final part of the digestive tract is the colon, which is further divided into four parts: the ascending colon, transverse colon, descending colon, and rectum. A vital role is played by the colon in the digestion of food, and therefore the development of cancer in this area can disturb the digestive system. Colon cancer usually begins with a small tumor known as polyps. Often no symptoms are shown at the earlier stages. Abdominal pain, weight loss, and blood in the stool are some symptoms that can be seen in the later stages.

1. Stage 0
It is the non-cancerous stage where the polyps start growing inside the colon. A lining of the polyps is formed inside the colon. At this stage of colon cancer, the growth of polyps is confined to a particular place and this condition is termed as “carcinoma.” Treatment at this stage can prevent from turning the cells into cancerous cells.

2. Stage 1
This is the stage where the cancer starts developing by spreading into the inner lining of mucosa and starts affecting the submucosa. The cancer cells tend to spread into the muscles if not diagnosed and treated at this stage of colon cancer.

3. Stage 2
In this stage the disease has spread beyond the mucosa and submucosa. This stage of colon cancer is further divided into three types:

• Stage 2 A – In this stage the disease further spreads into the serosa, a tissue of the intestine that is made of serous membrane. In this stage the cancer does not affect the organs or lymph nodes.
• Stage 2 B – All the layers of the colon – mucosa, submucosa, and serosa are affected by the cancer; however, the distant organs and lymph nodes are not yet affected.
• Stage 2 C – The nearby lymph nodes start getting affected in this stage, but the distant organs and lymph nodes remain unaffected.

4. Stage 3
This stage of colon cancer is further subdivided into three categories:

• Stage 3 A – As the cancer has already spread into the mucosa and submucosa in this stage, it starts entering into the muscles. It may affect the nearby lymph nodes from the origin of the tumor.
• Stage 3 B – In this stage four or more lymph nodes might have been affected, including the nearby organs and tissues.
• Stage 3 C – The cancer cells or tumor has spread and involved more lymph nodes and also started affecting the nearby organs. This stage of colon cancer is difficult to treat and requires detailed treatment.

5. Stage 4
An advanced stage of colon cancer, where the tumor has spread to distant organs like the liver,lungs, or even the brain. This stage is further divided into two categories: Stage 4 A, wherein the cancer affects only one organ, and Stage 4 B where more than one organ is affected.