Colon cancer is a type of cancer that starts in the large intestine, which is also referred to as “colon.” Older adults are at a higher risk of contracting this type of cancer, but it can also affect people from other age groups. It starts when non-cancerous cell clumps known as polyps are formed inside the colon, and, over a period of time, these polyps become cancerous. Colon polyps may be accompanied by some symptoms, for which doctors advise undergoing regular screening tests to prevent them from turning cancerous. The tests help in detecting and removing polyps before they transform into cancer. Colon cancer is alternatively referred to as colorectal cancer, which is a term that combines both colon and rectal cancer. This article explains the stages of colon cancer in detail.

Doctors determine the stage of colon cancer after an initial diagnosis, which may involve several tests. Every test will help the doctor to identify the extent to which your body is affected by cancer. Here are the different stages of colon cancer that you should know about to treat the disease effectively:

1. Stage 0
At this stage of colon cancer, abnormal cells are formed in the mucosa or wall of the colon. This stage is also known as carcinoma in situ, which means that cancer is only present in the cells where it started and has not spread to any adjacent tissues.

2. Stage I
During this stage, cancer invades the submucosa, which lies below the mucosa and is the inner lining of the large intestine. In this stage of colon cancer, there is also a possibility of malignant cells impacting the colon wall’s deeper muscle layer. However, these cells have not invaded any areas that are outside the colon.

3. Stage II
During Stage II, cancer spreads past the colon wall but does not impact the lymph nodes. This stage is further divided into three categories: stage IIA, IIB, and IIC. At this stage, cancer spreads to the outermost layer of the colon wall or serosa, but it has not spread beyond the wall. Alternatively, it spreads past the serosa and affects the tissue lining of the abdominal organs, and it may or may not have impacted any adjacent organs.

4. Stage III
During Stage III, cancer spreads past the colon lining and affects the nearby lymph nodes. However, distant lymph nodes and other organs of the body remain unaffected. Stage III is further divided into three categories: IIIA, IIIB, and IIIC. One to six lymph nodes might be affected by cancer at this stage.

5. Stage IV
At this stage, cancer spreads through the blood and lymph nodes to other, distant organs in the body, or to a distant lymph node. The organs affected at this stage may include the abdominal wall, ovary, liver, or the lungs.