Cancer is the abnormal and uncontrolled growth of cells and when this cancerous growth is observed in the colon; a part of the large intestine, it is referred to as colon cancer. Colon cancer begins as a small lump of cells, called polyp which becomes cancerous if left untreated. Some of the symptoms of colon cancer are weight loss, rectal bleeding and difficulty in bowel movement.
Stages of colon cancer
Identification of the stage of cancer is crucial for the proper treatment of the disease. A common system used for the identification and staging of colon cancer is called the TNM system. The TNM system raises the required questions which allow doctors to treat the condition accordingly.
- Tumor (T): How deep has the tumor grown into the wall of the colon or rectum?
- Node (N): Has the tumor spread to the nearby lymph nodes? Where and how many lymph nodes are affected?
- Metastasis (M): Has cancer moved or metastasized to other parts of the body? If so, where and how much?
Based on this system, colon cancer is divided into four stages depending upon the symptoms and the extent of metastasis.
- Stage 0: In this stage, the cancerous growth is limited to the mucosal wall of the colon only. In this stage, the cancer is called in situ and it can be removed with the help of a small surgery.
- Stage I: Stage I is characterized by the spread of the tumor cells to the mucosal and sub-mucosal layers of the intestine. However, the growth is still in the colonic area only, and complete removal of the polyp can prevent the further advancement of cancer.
- Stage II: Stage II cancer is when the cancer has spread beyond the walls of the colonic mucosa but not reached the lymph nodes. This stage is further subdivided into three stages:
–Stage IIA: Cancerous cells have reached the serosa layer but not beyond it.
–Stage IIB: Cancer cells have crossed the serosa but not yet affected other body organs.
–Stage IIC: In this aggressive stage, cancer has reached nearby organs also and is said to have metastasized.
Stage III: In stage III, lymph nodes have been attacked by the cancerous cells. However, other body organs are still unaffected. Stage III has three subcategories (IIIA, IIIB, and IIIC) depending on the layer of the colon in which the cancer is present and the number of lymph nodes affected by cancer.
- Stage IV: Stage IV is the most advanced stage of colon cancer and in this stage, several other body parts such as the liver and lungs are attacked by the cancerous cells. Two sub-categories of stage IV cancer are:
Stage IVA: When only one body organ is affected.
Stage IVB: When more than one body organ is attacked.
Colon cancer is divided into four categories and several sub-categories based on the aggressiveness of cancer. It is important to note here that early diagnosis and treatment can significantly reduce the chances of death due to colon cancer.
