Colon cancer starts in the large intestine or colon of the human body; which is located at the end of the digestive tract. This cancer type primarily affects older adults, but it can occur at any age.

Based on the progression of the symptoms, colon cancer is categorized into various stages. The main stages of the condition typically refer to the extent of cancer or how far it has spread. This article explains the main stages of colon cancer in further detail.

Stage 0
This is the beginning of colon cancer. In this stage, the condition does not grow beyond the innermost layer of the colon or the mucosa.

Stage 1
The symptoms of colon cancer grow into the inner layer of the colon to the next layer of the colon or submucosa. In this stage, it does not yet spread to the lymph nodes.

Stage 2
The development of slightly more advanced symptoms than in stage 1 is referred to as stage 2 of colon cancer. In this stage, the cancerous development grows beyond the mucosa and the submucosa of the colon. This stage of cancer is further classified into three sub-stages which are known as stages 2A, 2B, and 2C.

• Stage 2A
  Cancer does not spread to the lymph nodes or nearby tissue. However, it reaches the outer layers of the colon.
• Stage 2B
  Cancer grows through the outer layer of the colon and to the visceral peritoneum, but lymph nodes are yet to be impacted in this stage.
• Stage 2C
  In this stage, cancerous development does not appear in the nearby areas of lymph nodes. But, it spreads through the outer layer of the colon and also affects the nearby organs or structures.

Stage 3
Stage 3 of colon cancer is classified into three sub-stages, viz. stages 3A, 3B, and 3C.

• Stage 3A
  The tumor of colon cancer grows through the muscular layers of the colon and can be found in the nearby lymph nodes. However, it does not get spread to the distant nodes or organs in this stage.
• Stage 3B
  The tumor has grown through the outermost layers of the colon and further penetrates the visceral peritoneum. It also invades other organs or structures and is found in one to three lymph nodes.
• Stage 3C
  In this stage, cancer grows beyond the muscular layers. Besides this, there are developments visible in four or more nearby lymph nodes.

Stage 4
Stage 4 of colon cancer is classified into two sub-stages, viz. stages 4A and 4B.

• Stage 4A
  Cancer spreads to one distant site, for example, to the lungs or to the liver.
• Stage 4B
  It is the most advanced stage of colon cancer. In this stage, cancer spreads to at least two or more distant sites such as the liver and lungs.

During the early stages of the condition, the symptoms of colon cancer are not prominent or not visible. Hence, it is crucial to look for some warning signs such as changes in bowel habits, blood in stools or rectal bleeding, abdominal pain, fatigue or unexplained weight loss, in case there is any reason to suspect the development of cancer.