Also termed as colorectal cancer, colon cancer is caused when a small lump of cells forms on the lining of the colon or rectum. These small lumps or abnormal tissue growths are termed as polyps. Over a period of time, some of these polyps may turn cancerous. There are multiple stages of colon cancer depending on a treatment method advised by the doctor.

What are the symptoms of colon cancer?

Constipation or diarrhea, a change in the consistency of stool, a feeling that the bowel doesn’t empty completely, weight loss, weakness, and bloody stools are some signs that need immediate medical intervention.

What are the stages of colon cancer?

Stage 0

This is the first stage of colon cancer, wherein polyps are found in the inner lining of the colon or rectum. There is no effect of these polyps otherwise as they haven’t spread to the other layers of the colon or rectum, and this stage is also known as carcinoma in situ. It is the earliest form of cancer and does not spread to the surrounding cells.

Stage I

The cancer spreads to the next layer of the colon, that is, the submucosa, but it does not spread to the lymph nodes. The survival rates of patients diagnosed with colon cancer at this stage are quite high. Surgery can cure cancer at this stage, and there are low chances of recurrence.

Stage II

This stage of colon cancer is categorized into 3 categories:

• Stage II A: Cancer grows up to the outermost layer of the colon or rectum. It does not grow through this layer and does not spread to any other organs.
• Stage II B: This stage affects all the layers of the colon or rectum.
• Stage II C: At this stage, cancer spreads to all layers of the intestine and has spread to nearby organs and tissues.

Stage III

This stage is further subdivided into 3 categories:

• Stage III A: The intestine wall is further affected in this stage, and cancer spreads to up to 3 lymph nodes in and around the primary tumor.
• Stage III B: Cancer spreads beyond the outermost layer of the colon or rectum. Nearby organs and tissues start getting affected, but distant organs are unaffected up to this stage.
• Stage III C: Cancer spreads to at least 4 lymph nodes and to the nearby organs.

Stage IV

This is the last stage of colon cancer, wherein cancer metastasizes to distant organs like the liver or lungs. This stage is further classified into two depending on how far the cancer has spread, the lymph nodes, tissues, or other organs:

• Stage IV A: Cancer spreads to one organ.
• Stage IV B: More than one organ is affected.

It is vital to understand that normal blood tests cannot detect colon cancer. Doctors may consider testing for a chemical that is sometimes produced by colon cancer, that is, carcinoembryonic antigen or CEA. The level of CEA is a basis for the detection of cancer.