The TNM staging system is used to determine the stage of colon cancer.

The following elements are included in the TNM staging system:

Tumor (T) is an abbreviation for tumor. This metric measures how far the cancer has spread into the colon's wall. The mucosa, which is the inner lining, the sub-mucosa, which is the fibrous tissue beneath the muscle, the muscularis propria, which is a thick muscle layer, and the serosa, which is the outermost covering layer, are the layers that make up the muscularis propria.

Nodes of the lymphatic system (N): If the malignancy has progressed to the lymph nodes, this factor shows it.

The term "metastasis"(M) refers to whether the cancer has spread to other places of the body.

The malignancy is categorised and assigned a number or letter that shows the severity of the disease within each stage. These numbers and letters are assigned according to the extent of the cancer's spread.

STAGE 0 COLON CANCER

  • This is the earliest stage of colon cancer, and it indicates that the disease has not progressed beyond the mucosa, or the colon's innermost layer.

STAGE I COLON CANCER

  • This indicates that the malignancy has spread to the mucosa and submucosa. The cancer has progressed deeper into the colon wall but has not spread to surrounding organs or lymph nodes in stage 1 colon cancer. Cancer that was a component of the polyp is also included in stage 1 colon cancer.
  • If the cancer-containing portion of the polyp was removed during a colonoscopy and no cancer cells were found at the margins of the excised piece, no further treatment may be necessary. If the polyp could not be entirely removed or if the polyp had to be removed in parts, making it difficult to identify if there were cancer cells at the edges, the patient may be advised to have additional surgery.

Stage 1 colon cancer probability

People with stage 1 colon cancer have a 5-year relative survival rate of roughly 92 percent.

STAGE II COLON CANCER

The cancer has progressed beyond the mucosa and submucosa in this stage, and has spread beyond the mucosa and submucosa. Stage 2 is further divided into stages 2A, 2B, and 2C. Colon cancers in stage 2 have progressed to the colon wall and surrounding tissue but not to the lymph nodes.

Stage 2 colon cancer prognosis

The relative survival percentage for persons with stage 2A colon cancer is 87 percent, while the relative survival rate for people with stage 2B colon cancer is 65 percent.

STAGE III COLON CANCER

Stage 3 is further divided into 3A, 3B, and 3C, with the distinctions based on how far the cancer has spread and the number of lymph nodes involved. Colon tumors in stage 3 have migrated to adjacent lymph nodes but have not yet spread to distant organs.

Stage 3 colon cancer prognosis

The five-year relative survival rate for those with stage 3A colon cancer is 90%. People with stage 3B colon cancer have a 72 percent five-year relative survival rate, whereas those with stage 3C have a 53 percent five-year relative survival rate.

STAGE IV COLON CANCER

It is the most advanced stage, as it indicates that  the disease may have spread to other parts of the body, such as the liver or lungs. This stage is broken into two parts: 4A and 4B. Colon cancers in stage 4 have progressed from the colon to other organs, such as the liver. The cancer can also spread to the lungs, brain, and the peritoneum, which is the lining of the abdominal cavity.

Stage 4 colon cancer prognosis

The 5-year survival rate for people with metastatic or stage four colon cancer is only 12%.