Colon cancer, also known as bowel cancer or colorectal cancer develops when cells that line the rectum or colon grow uncontrollably and become abnormal. Unfortunately, colon cancer symptoms usually won’t manifest until the disease is in the advanced stages. This is the reason why regular colon cancer screenings are recommended.
While not applicable in all cases, most colon cancers typically develop from pre-cancerous or adenomatous growths. These growths or polyps can further evolve once abnormalities or mutations occur in their cell DNA. Diet, family history, smoking, and alcohol intake are some of the most common risk factors for the condition.
How Colon Cancer Develops
In a typical human body, the cells of the body will grow, divide, and eventually die to ensure that the body functions properly and stays healthy. However, there are occurrences when the cells survive beyond their expected lifespan and continue to grow and divide. When the cells that line the rectum and colon multiply uncontrollably, colon cancer can occur.
Most colon cancers start as serrated or adenomatous polyps. Typically, the polyps will grow slowly and no colon cancer symptoms will develop until they have become cancerous. However, there is an opportunity to detect and remove the polyps before they develop into cancerous cells during the pre-cancerous stage.
The Different Stages of Colon Cancer
The condition is clinically described based on the stage when it was discovered. Different stages of colon cancer are identified based on a few factors including:
- The spread of the cancer to the other organs (also called metastases)
- The lymph node involvement (also known as drainage nodules)
- The depth of the cancer’s invasion through the intestine’s walls
In many cases, colon cancer treatment involves the surgical removal of the parts of the intestine that are affected (also known as colon resection surgery). In other cases, chemotherapy, tumors, and radiation are recommended to manage the condition effectively. Below are the various stages of colon cancer:
This stage is also referred to as carcinoma-in-situ. In this stage, the growths are limited to the linings of the rectum or colon. The lesions are considered pre-cancerous. Removing the lesion through colonoscopy or polypectomy may be done. Surgery may be required if the lesion is too big.
At this stage, the cancer has grown in the intestinal walls. However, it has not invaded the lymph nodes or the muscular coat of the intestinal wall. Standard treatment at this stage is colon resection. The process involves removing the lymph nodes and the affected parts of the colon.
This stage is divided into three:
- IIA – cancer has spread to colon walls
- IIB – cancer has penetrated the large intestine’s muscular layers
- IIC – cancer has spread to the tissues that are adjacent to the colon walls
At this stage, the condition has not affected the lymph nodes yet. Surgical resection is recommended at this stage. Surgical resections at this stage may be followed or preceded by radiation or chemotherapy depending on histological results post-resection.
This is considered the advanced stage. At this point, the cancer has reached the lymph nodes and the patient usually requires chemotherapy. There are also three sub-stages in this stage.
- IIIA – cancer has moved past the colon and has spread to the lymph nodes
- IIIB – there is advanced lesion present in the colon walls
- IIIC – cancer has affected the adjacent tissues of the organs found in the abdomen
At this stage, the cancer has metastasized or spread to other organs like the ovaries, liver, and the lungs. This stage is also divided into three.
- IVA – cancer has spread to lymph nodes and organs that are far from the colon
- IVB – cancer has affected more lymph nodes and several distant organs of the body
- IVC – cancer has affected distance organs, lymph nodes, and the abdominal tissues